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Hi, everyone, and welcome back to Behind the Knife. We're your surgical oncology team, and today we're really excited to present a topic which we all agreed we could talk about for several hours, neuroendocrine tumors of the small bowel. I'm Elizabeth Barbera. I'm a PGY6 from Brooklyn.
Medical Center. I couldn't join the team for the discussion, but I'm happy to rejoin for our next episode, which is going to be a journal club presentation where we do a deep dive into the literature for the medical therapies we have to offer for neuroendocrine tumors. I'll let the rest of the team
introduce themselves and thanks for listening. I'm Connor Chick. I'm a second year fellow at Ohio State. I'm Lexi Adams. I'm a first year fellow at MD Anderson. Pembryon staff at BAMC. Otherwise known as Brook Arming Medical Center. We'll start with a case. Lexi, you're seeing a 50-year-old man in clinic who's referred for an incidental finding of a mesenteric mass on a non-contrast CT scan that was done for kidney stones.
In terms of his history, he has well-controlled hypertension, no surgical history, he's on lisinopril, he doesn't smoke or drink, and he has no family history of any cancers. So what elements of the history do you want to ask about first, and then what would you look for on exam?
So I would ask this patient about symptoms that could include abdominal pain, change in bowel habits, any obstructive symptoms, weight loss, fevers or chills, night sweats, any other changes to his health. And then on exam, I, of course. at his vital signs perform a cardiopulmonary exam to listen for a murmur and an abdominal exam to evaluate for a palpable mass and i would also examine all his nodal basins yeah so he has no other symptoms
So in terms of thinking about the differential, so oftentimes these mesenteric masses represent enlarged lymph nodes. Those can be regional nodal metastases from somewhere in the GI tract or elsewhere in the abdomen, sometimes a primary lymphoma. Sometimes mesenteric masses can represent a desmoid, since these often arise in the mesentery, or they can even be non-neoplastic inflammatory diseases or even cystic lesions, which are usually benign.
And then when we think about the GI tract primary sites, nodal mets from neuroendocrine tumors often form a mass in the mesentery, but this could also be peritoneal metastasis or other nodal metastasis from something like a gastric or appendiceal or a colon cancer. So for this patient, we got some basic labs, including a CBC and a chemistry, and those are normal.
we looked at the ct scan without contrast and there was a three and a half centimeter mass in the small bowel mesentery with pers with some peripheral calcifications what should we do next to work this out Given those CT findings, I am concerned about a nodal metastasis, and this could be from something like a small bowel neuroendocrine tumor, but the findings are pretty nonspecific, so I would start by repeating a CT abdomen pelvis, but I'd get it with IV contrast this time.
And I'd make sure that I'd ask for both arterial and delayed venous phases. I'd also add some LFTs. And then as far as my concern for neuroendocrine tumor, some people add chromogranin A's historically, but it's not very sensitive or specific, and it doesn't often change management decisions. There's another tumor marker called pancreastatin.
That's also a little more sensitive for neuroendocrine tumors, but it's not necessarily part of the guidelines at this point. Yeah, it was interesting that recently the NANETS guidelines dropped chromogranin from their...
their recommendation so i think a lot of people still get it but like you said it's falling out of favor because it's neither sensitive nor specific yeah at our institution we actually don't even include it in our workup anymore yeah i would say here it's it's variable some people do some don't So we get the CT scan. There's a mass in the mesentery measuring three and a half centimeters. It's in proximity to, but not involving the ileocolic artery and vein.
There's no other obvious mesenteric masses. There are a few small liver lesions that seem a little brighter on arterial phase, but we don't see a small bowel mass. What are our thoughts now about the differential and the next steps? I still am concerned about neuroendocrine tumor. Generally, the primaries are very small and often you can't see them on imaging.
I would then proceed with a dotatate scan to take a closer look at the liver lesions and see if they're avid. And then I would refer them for a tissue diagnosis of one of those liver lesions as well. I think a couple of comments there. I think arguably tissue diagnosis may not be needed in all these cases. So you'll almost never get a tissue diagnosis of the primary because like you said, the primaries are generally very small and kind of hard to find.
you're not going to go biopsy a node in the middle of the mesentery and the other thing that's changed now is there's dotatate right so there's not a lot of things that are dotatate avid although there can be some false positives but most of the time if all these things light up on dotatate you kind of have your answer now you know
If you want to go with medical therapy, the medical oncologist may require a tissue diagnosis. But if you're going to go to the OR anyway, you might not need a tissue diagnosis. The other thing is just the... Imogene you brought up there is very characteristic of neuroendocrine. So you guys talked about differential, which I think is good, but this no longer really sounds like a lymphoma. When I give a lecture on this, I draw this triangle like a normal.
well, not normal, but a GI adenocarcinoma, the primary tumor is big and the lymph nodes are small. So you'll almost always have some indication of a primary before you have big lymph nodes in the mesentery.
neuroendocrine being the exact opposite of that so you can have these big giant nodes and the you know two millimeter primary so you have to kind of invert that uh paradigm that you normally think of where the lymph nodes come late and the primary tumor is very big before you see big visible lymph nodes on a ct scan the exact opposite is is true for neuroendocrine so you'll have very small primaries
big nodes and then what's the other weird thing about primaries for small bound or endocrine that in my opinion changes the way you have to do the operation every time so they're often multifocal so you really have to it's mandatory that you palpate and feel the bowel and you're feeling for masses that are sometimes like grains of sand they can be really subtle so you it's not like a trauma x-lap running of the bowel you're very slowly
running the bowel and feeling for those tiny little tumors. Exactly. And you'll see debates about whether or not you should do these cases MIS. You know, some people will say, oh, well, just take the lymph node and then take any bowel that's being drained by that lymph node. In my hands, in my opinion, it's mandatory open operation.
so that you can run the small bowel with your fingers to find those masses i don't think there's i don't think it's possible to adequately run the small bowel for these tumors mis so these should all be done open in my mind the other thing is that
You're going to go way to the base of the mesentery, which is not very safe MIS. And probably you won't be as thorough in your lymphadenectomy MIS. Yeah. I mean, I would say at our institution, we're, we're fairly aggressive about minimal invasive approaches.
But all of these are done open for that, for that exact reason. The only other consideration for, I think, biopsy prior to the Dota is insurance approval for a PET scan, because sometimes those won't get approved if you don't have a real diagnosis yet. you know the alternative in that situation if there's nothing really to biopsy might be to just get an mri of the liver to get a better assessment of the volume disease in the liver with the idea that you're still going to go to the operating room
It's just a question of what exactly are you going to be doing. I do think most patients were able to get a dotatate beforehand. But in this case, we got a liver biopsy, and it returned as a well-differentiated neuroendocrine tumor's grade one with a KI-67 of 1%. so just to talk about the pathology for these so for gastro gastroenteropancreatic neuroendocrine tumors which is sort of the category of neuroendocrine we're talking about the degree of differentiation and the ki 67 are
critical components of the pathology report. So that tells us about disease biology, it tells us about prognosis, and then it also can influence which imaging modalities we can use and even which systemic therapies might be helpful. in terms of discerning neuroendocrine versus something else so like an adenocarcinoma for example lexi what are what are some of the special stains that we sometimes will do to differentiate these so sometimes it's
Challenging for pathologists to identify these well-differentiated neuroendocrine tumors. So some of the stains that they use that are specific to neuroendocrine are TTF1, synaptophysin, and chromogranin, and then some specific stains. to GI adenocarcinoma instead of neuroendocrine would be CK7 for upper GI cancers, CK20 for lower GI, and MUC1 for mucinous neoplasms. And of course, there are many others in the alphabet soup, but these are some of the most common.
I would say the most important things to look for, like we said, are the well-differentiated versus poorly differentiated, and then the KI-67. So that also will help us determine the grade, and in most cases, actually based on the KI-67. So in terms of next steps for this patient, who has a well-differentiated, likely small bowel neuroendocrine tumor, it's grade one, KI-67 is 1%, that has lymph node metastases and liver metastases.
He has no symptoms of carcinoid syndrome, so it's one of the things that we should know beforehand. But in general, we're going to move forward with surgery. So to get a better sense of the extent of disease, we're going to get a dotatate scan.
so dotatate is a pet scan that demonstrates areas with high expression of somatostatin receptors so dotatate is the molecule that's used instead of fdg and dotatate refers to a gallium-68 labeled somatosatin receptor analog so the dota part of that is a chemical that binds gallium-68 and then the
t-a-t-e or the tate at the end stands for tyrosine 3 octreotate so that's the somatostatin receptor binder it's amazing how few people understand this so you know you don't need to know what these all these fancy words mean but When you talk about a PET scan, most people mean an FDG PET, which is tagged glucose and it lights up hypermetabolic areas either from an aggressive cancer or from infection.
A low-grade neuroendocrine tumor, very slow-growing cancer, will not light up on an FDG PET. So you have to get a dotatate PET, which, like you said, is going to light up things that have somatostatin receptors.
It's amazing. You'll have like medical oncologists that will order FDG pets for a neuroendocrine tumor. So that's a really key thing to understand when you're ordering imaging for these because you're going to order a PET scan, but you don't get an FDG pet, you get a dotate pet. So sorry to harp on that.
you know if this if our patient instead of having a well-differentiated neuroendocrine tumor had a poorly differentiated or a neuroendocrine carcinoma for example sometimes those tumors actually can lose this amount of satin receptor expression because they're so poorly differentiated
and dota can actually be less sensitive for those than it is for well differentiated so that's one of those that's kind of counterintuitive like you're saying the fdg pet typically will light up brighter and more aggressive disease and dota is the total opposite so now we have hit the dotatate scan and the mesenteric mass is highly avid and there's a few avid lesions within the small bowel but it should be noted that
Dotatate's not good for looking for intraluminal neuroendocrine tumors because there's physiologic uptake within the bowel anyway. So that's really no substitute for... feeling and running the bowel in the OR. But the patient also has one three-centimeter liver lesion in segment five, and then four or five smaller lesions located peripherally in segments two, three, six, and seven. So as we've...
mentioned before, the mainstay of treatment for these well-differentiated tumors is surgery. They don't particularly respond well to chemotherapy. And while somatosap...
somatostatin receptors can play a role in slowing disease progression. They're not likely to shrink or eliminate the tumors like chemotherapy sometimes does for more aggressive cancers. Yeah, so one of the other systemic therapies we should... talk about and we will get into more detail on this later on is prrt so that is that stands for peptide receptor radionuclide therapy
which sort of falls under this category of theranostics so it sounds really cool but basically what it is is it combines an advanced imaging technique with a therapeutic and so in this case it's using that same
somatosetin receptor expression that dotatate uses and then instead of using using gallium 68 to light up on a scan dotatate is coupled with lutetium 177. and so the brand name for this is ludathera the in in general it's referred to as prrt and the goal is to deliver targeted radiation to areas that express somatosatin receptors now in this patient the thing we need to think about is the mesenteric mass because
when you give prrt often it will cause this dense fibrotic reaction and you get this desmoplastic reaction within the mesentery that can actually do a bowel obstruction so for patients like this who have their primary and nodes intact that's not a great option for this patient at this point although there certainly could be a role down the road and we'll talk about that later on yeah i think just to
simplify that a bit ludifera is cool it works on the same technology as the dotatate if you light up on dotatate you should respond to prt but it should be way down the algorithm like it's kind of a last-ditch effort really um for the most part. And that's in part because what you talked about, in part because it has real and meaningful side effects that a lot of the other therapies don't. But the mainstay, of course, is surgical resection. So we should talk about that.
I do want to just make a broad point about surgical resection of these tumors. This is a very slow-growing disease, right? We just heard KIS-67 of 1%. If this patient's like 80... The chances that this disease is what gets them is very, very low. Even if they're 60, you know, the chance that this is what kills this patient is pretty low. So the majority of the time we're operating on these patients, it's to alleviate some kind of symptom.
Now, most patients will have bowel symptoms by the time they present, so this patient did not present with that, but a lot of patients that you'll see in clinic will have some vague quasi-obstructive symptoms. And so just keep that in mind and let's, you know, talk about what operation to do and why to do it. The other symptom I feel like I've come across a couple of times is almost a chronic mesenteric ischemia type symptom where.
patients will have postprandial pain and almost kind of food fear when these mesenteric masses get really big and it does get better when you take those out so i just think that's really interesting yeah absolutely in terms of the operation So for this patient who we think has a small bowel primary, most likely has mesenteric mass or nodes, and then some what seems like pretty low volume liver disease.
So our plan for this patient would be exploratory laparotomy, small bowel resection, resection of the mesenteric mass, and then liver resection and or ablation. So in terms of the sequence of the operation, there's probably a few ways you could go about this. But Lexi, you want to kind of talk through what would your approach be for this particular patient?
So I would plan on an open operation and do an exploratory laparotomy with planned small bowel resection along with resection of all the associated mesentery. So as far as logistics of how that looks, I would start with running the bowel. That would be... kind of a slow palpation, a feeling for tumors that can be as small as a grain of sand. And then I would also look at the mesenteric disease and identify which pedicle.
ran with and plan for a high ligation with all of the associated mesentery in that area. We'd also do a thorough inspection of the peritoneum and look for any peritoneal disease that we could take as well. Yeah, I think that's exactly the right way to start. A couple comments. I always mark what I think is the most proximal and distal tumor before I start cutting anything, and then I run the small bowel twice.
So every once in a while, you'll find that by the time you've run the small bowel and felt all the primary tumors, there's like 10 or 12, and you're only going to be left with 100 centimeters of bowel or something like that.
and you may be in some of these cases you may be stuck with the decision of knowingly leaving behind a tumor or the other kind of wild thing that i've done before is you literally just cut out the piece of small bowel that has that tumor and then close it primarily in two layers and that you know that because if there's one tumor that's like 40 centimeters proximal to the next one you don't want to necessarily take the 40 centimeters of intervening bowel even though that's
oncologically very unsatisfying sometimes you have to make compromises in these cases where they have small bowel neurotic tumors basically throughout their entire ilium and part of their jejunum and things like that so you run the bowel you mark the proximal and distal tumors run it again make sure you're happy before you cut any bowel the other thing is
Much like a Whipple operation, a lot of this operation is planned in my head before I go to the operating room based on the CT scan. So you can, you know, with a triple phase scan.
You can get a lot of detail about the mesenteric vessels, which ones you are going to take, which ones you're going to leave, what bow you're going to leave behind and how it's going to be perfused before you get to the operating room. Every once in a while, you'll be surprised and there'll be, you know, certainly more.
primary tumors than you expect but particularly around that iliocolic vessel and what vein is going to be left to drain the you know the the right colon if you're going to leave it Those are things that I really try to plan out in my head. And then as I'm exploring the mesentery, I try to kind of match those things up. Sometimes I'll use an ultrasound to understand the relationship between the SMB and the tumor. And then that mesenteric resection, it all comes down to the SMB, just like.
Every GI operation, in my opinion, comes down to the SMB. It's like a right colon in my mind. The first thing I do is that medial dissection. I try to get out the SMB. understand where it's at peel the tumor off of the smb leave as much as you can and then take what you have to take and again usually that branch that you have to take will already be occluded by the tumor. And so that can be planned out.
before you get to the operating room. And then you want to make the anatomy look in the operating room like it did on the CT scan. And that's how you avoid getting in trouble. I think the way that people get in trouble in these cases is they use a ligature impact. They cut the bow, and then they go chomp, chomp, chomp with the Ligature Impact, and they end up taking a big branch of the SMB that they didn't need to take.
and then they end up having to take more bowel than they need to, or they're doing an anastomosis to bowel that's kind of sketchy, and then they have a leak, things like that. So I think starting central.
and doing a really thorough job of understanding the branches of the SMB and the SMA, that's how you stay out of trouble in these cases because you really are going to be high in the mesentery and higher than a lot of people are comfortable. So I think the other... operative consideration we should talk about is how to approach the liver so in this patient we said there were small peripheral lesions in seconds two three six and seven you know if if these are all
peripheral and and you know visible on the external surface of the liver we may just do some wedge resections for all of those i think the some one of the some of the harder decisions are when there's lesions that are a little bit deeper you know maybe not the
very central lesion right on the right inflow or the right apatic vein, but, you know, something that would require a bigger resection. So Dr. Vreeland, can you kind of talk to us about how you approach some of those more intermediate liver tumors? Yeah. I think that ultimately the question you have to ask yourself on these cases is why am I here? Why am I in the operating room? Right. And again, this isn't.
colorectal liver mets, assistant pancreas cancer, these things are not going to grow quickly. They are going to grow very slowly. There is medical therapy that can keep them at bay. So you always need to live to fight another day. Don't do a dangerous resection to clear these patients' liver. There's also a bit of confusion, I think, because there's a body of literature about debulking.
these tumors, right? So, you know, there's literature that says you should debulk 80% or 90%, and that's considered a successful resection. A couple things to keep in mind there. One, The majority of that is retrospective data. And so the patients who, you know, are able to be debulked are going to do better because they have less disease. Got it. Great. So debulking is good if you look at it from a retrospective standpoint.
Two, debulking makes a lot of sense to me in a tumor that's making hormones. So we haven't done a lot of discussion about how these can be hormonally productive, but you guys talked about carcinoid syndrome. So if you have a patient with carcinoid syndrome,
and a bunch of liver mets, then debulking those liver mets to try to get them down to a very small volume of disease or no disease that is producing that hormone makes sense. And you should be a little more aggressive in those patients because you want to stop. them from producing those hormones so and then so that's one reason right so to debulk the disease that's one reason to be in the operating room got it
The other one is to render them disease-free. Why do you need to render them disease-free? In the case of colorectal liver mets, you know, you want to get them off chemo, basically, in my mind. So you want to give them, well, one of my mentors always called chemo-free survival time.
you want to offer them an opportunity to not have to go on a somatostatin. So if you can clear all the disease that they can see on imaging, then they don't have to be on medical therapy. If you leave a tumor behind, that's where things get a little complicated. A KI-67 of 1%. If there's one little lesion that's deep in the liver and I'm going to have to like do a big liver resection.
Or let's say you get in there and you can't find it on ultrasound because it's two millimeters and it's in the back of the liver. I don't sweat it because this is a two millimeter or five millimeter lesion that has a KI-67. of 1%, it's not going to grow over, you know, multiple years. So it might be four, five, six, seven years before that patient has meaningful growth in that lesion and requires a somatostatin analog or some medical therapy.
And so you just have to always keep in mind what disease you're treating and what your goal is. So I know that's, you know, and it is very nuanced and very complicated, but I think to your point, if it's easy to get rid of, go ahead and get rid of it because then.
We don't have to stare on it on the next set of imaging and decide whether or not to start medical therapy. If it's really difficult to get rid of, only do it if there's a reason. Now, if it's a big tumor and you're worried that it's going to start producing hormones...
I think it's reasonable to resect, especially if they're kind of young and healthy. Again, if they're 80 and they have this disease, you really should only be operating if they're symptomatic because, you know, it's not likely to kill them. And then it gets even more complicated when now we have a little bit higher KI-67 and now we are worried that it's going to progress. And should you, you know, should you resect in those cases? The reality is that even if you clear the liver.
you know there's microscopic stuff that you're leaving behind. And so you always have to sort of keep that in mind is that, you know, heroics in, you know, in other diseases, we clean up with chemo or we treat with chemo. And so we're going to be surgically a little more aggressive because the microscopic stuff we can take care of with chemo. In neuroendocrine tumors with a low KI-67, chemo doesn't work.
You, as you guys said, you can give medical therapy, but it's more static than CIDL. So it'll prevent progression, but it's not going to kill microscopic disease. And so, you know, you just always have to keep these things in mind that. We can only do so much with surgery. And in a very slow, progressing tumor, you should not go doing big whacks for small tumors that aren't going to have a clinical consequence anytime soon.
So it is very case-by-case and nuanced, but I think those are kind of the general principles is really understand your why when it comes to operating a metastatic disease for a well-differentiated, indolent disease like this. And I think another... important tool to remember is ablation, whether it's OR and you can see it on ultrasound and ablate it there, or if it's small and you can't find it, again, remembering that if it grows in eight, 10 years, that IR can always ablate it later.
Yeah, and I've had that case come up where I can't find it on ultrasound in the operating room, and I wanted to ablate it, and I just leave it alone. And when it gets bigger, then IR can ablate it, like you said. So if it's too small to see, then it's too small to have clinical consequence.
and it'll get bigger eventually, and then it'll be easier to treat. But I do think that the primary tumor... is the more important thing to resect here not because it's more curative or anything like that it's because the you know one thing we didn't mention on the imaging early is that these tumors have this
very severe desmoplastic response around them in the mesentery. And they tend to suck the bowel into the mesentery. And so they almost uniformly will cause a bowel obstruction if you don't operate. And so... In my hands, everybody with a small bowel neuroendocrine tumor gets a surgery because if it hasn't caused a bowel obstruction yet, it's going to. And what you don't want to do, especially if the patient's not super reliable, is, you know.
A lot of times these patients present to the hospital because they have a bowel obstruction and now it's like you have to operate and they're malnourished and you're like putting them on TPN per week just to get them tanked up a little bit and then having to operate. in that kind of acute setting it's great to avoid that and so if you have a patient who's a little bit obstructed i would go ahead and operate then
because eventually they're going to be more obstructed. And the primary tumor is what kills these patients in the majority of the disease. So what do most of these patients die of eventually? Bell obstruction. Bell obstruction. Yeah. So even if you do a great job, they may recur in their mesentery and that'll suck the bowel in and they die of malnutrition from bowel obstructions. So be extremely aggressive in the mesentery.
and be less aggressive in the liver. It's kind of a weird paradigm shift, but that really, I think, is the best approach to these, is that the nodal burden is super, super important in this disease, so be as aggressive as you can. That being said... Sometimes you'll see like periaortic lymph nodes and lymph nodes that are away from the bowel and are not going to cause symptoms in the setting of stage four disease. I don't think there's a huge rationale to go after those.
They're not the ones that are going to be in the mesenary and cause that small bowel obstruction. And so being super aggressive about doing a periodic lymph node dissection and things. Those things don't make a ton of sense to me because they're not going to cause symptoms. Your why for these is generally either causing symptoms or you're going to try to clear them of all disease so they don't have to go on to medication. How do you handle lymph nodes in the Port Avidus?
What I would say is that those lymph nodes are generally not that hard to take care of. You know, there tends to be that like lowest node on the common bile duct, the one that's kind of right on the corner of the, you know, on the patient right of the common bile duct on the top of the pancreas there next. the duodenum. I've seen that one obstruct the duodenum for sure. And so I think those low portal nodes can cause duodenal obstructions. And so if you see those, you should clear them.
Doing a periaortic lymphoid dissection that has a lot of morbidity, you got to do a lot of surgery, and it doesn't make a ton of sense. So to shift gears a little bit, you mentioned carcinoid syndrome. So let's say that our patient that we talked about now has...
some concerning symptoms he's having flushing diarrhea so lexi before thinking about surgery what kind of things do we need to rule out and then what things would we do differently in the operating room in the setting of carcinoid syndrome you can develop carcinoid heart disease, which should take priority over the operation initially.
Because that can lead to acute heart failure and even hemodynamic instability in the OR. So sometimes these patients may even require a valve replacement prior to the operation. symptoms can be managed with somatostatin receptor analogs in the meantime. It's also, we've now multiple times mentioned how slow to progress this disease is, so it's not...
a huge rush typically for us to go to the operating room. We have time to optimize them medically. We have time to get their heart ready for the case. Ultimately, we just medically manage them until their cardiac symptoms are taken care of before proceeding to the OR. When you do bring these patients with carcinoid syndrome to the OR, you want to have a...
Good pre-op discussion with anesthesia. You can start them on an octreotide infusion perioperatively to prevent intra-op carcinoid crisis. One thing is that the long-acting octreotide analogs have helped a lot with that problem. Because if you get somebody on a long-acting octreotide analog and they're on it for a few months and then you give a dose kind of like a week before the operating room, you don't see the carcinoid crisis nearly as much in the operating room.
In some ways, that's a little bit of a problem of the past, but it's certainly something that gets anesthesia all excited and they'll have their drip ready and not typically use it. I think before we had the longer-acting ones, it was more of a problem. But most of these patients now get established on a long-acting actriotide analog, and it's less of a problem. So let's change our scenario.
Again, so now instead of having a mesenteric mass, the patient actually presented with a near obstructing mass in the duodenum. It's biopsied endoscopically and returns as... a grade two neuroendocrine tumor with a KS67% of 10%. And on imaging, there is resectable metastatic disease in the liver. Would your approach to managing this patient change at all? So again, you're...
trying to avoid heroic measures to debulk this disease. So if it's resectable endoscopically, that would be the first line for the duodenal mass. If it's not, then you could proceed with a segmental duodenectomy with... reconstruction, or if it is very close to the Ampecula, you might have to consider something like a Whipple. But again, you're trying to maximize your other options before getting to that point. I think if it's obstructing, it's probably not going to be...
you know, endoscopically resectable, but obviously that's best. The ones that I've seen of these have almost all been in D1. I think that's probably the most common spot. And a lot of times you can do kind of an antrectomy and then just really push.
It's pretty far under the duodenum and do an antrectomy D1 resection and get away with that. In the study of metastatic disease, I probably wouldn't do a Whipple, honestly. I just think it's too morbid. And these Whipples are not easy Whipples because...
they all have soft pancreases and normal ducts, right? So it's not like pancreatic cancer where you have the big duct and the hard pancreas where you don't worry so much about the leak. These are the ones that have leaks because their, their pancreas is very normal. Now that we're creeping up on the KI-67, right, so we've gone from 1% to 10%, you know, the cutoffs are 1 to 3, 3 to 20, and 20 and above for the different grades.
in that kind of 10% range is when I start worrying about them not being so friendly anymore. Now they're a little more aggressive. I think one trick is honestly to get, you can't always get it improved by insurance, but to get both types of PET scans, right? So if you get a dotatate PET and an FDG PET, it kind of helps you. tiebreak on whether this is a chemo kind of neuroendocrine tumor or a somatostatin analog kind of neuroendocrine tumor.
And so I might do that in this case with a, you know, with a K-67 of 10% and I'm not real sure what to do. If it's FDG Avid, I would probably give. some pre-op chemo and see if I can get it to shrink down or I can do more of a segmental resection and see whether or not it's worth being aggressive in the liver. So there's different chemo strategies here, but capecitabine and it's Cape Tem, I think it's temozolamide.
is kind of the standard of care for these well, what are called well-differentiated neuroendocrine tumors that are more grade two or grade three. And I think it'd be worth a shot in this case. And if they progress through that. then surgery is probably not going to help them. Then they're acting more like a higher grade. If they respond, then you kind of treat it like an adenocarcinoma and you can be more surgically aggressive after some response from chemo.
and one other thing to think about you know as we start moving up higher in those grades so there was a recent trial called net or two that looked at the addition of prt to somatosatin receptor analogs and their response rates were actually really impressive So in a patient who maybe has already had surgery for a small bowel primary with nodes and has liver disease primarily or...
something where you need a response and they can tolerate PRT, that may be a regimen to start to think about since there is randomized data for that now. Yeah. And I, I think that's where the, the two types of pet are helpful, right? Because. If they're light up on dotatate, then they should respond to PRRT. If they don't... and instead they're lighting up on an FTG pad, then PRRT is not going to be helpful. That's where you have to use chemo, usually in the form of Cape Town. One more scenario.
And one that probably comes up more on exams than in real life. But there's a patient who had an appendectomy for what was thought to be perforated appendicitis. But on final pathology, there's a two centimeter neuroendocrine tumor. Well-differentiated, but grade 2, Ki67 is 12%. There's no disease in the liver. How would you approach this patient? So I would counsel the patient on the need for a completion rate hemiflectomy with the goal of getting all of the...
high ligation of the iliacot pedicle to get all the lymph nodes associated with the area so again i think that principle of like small tumor big nodes like even though it's a two centimeter tumor there's a real risk of lymph node mets because these these tumors go to the lymph nodes so early and then what about
Let's say instead of a well-differentiated neuroendocrine tumor, the pathology comes back as a neuroendocrine carcinoma. So how does that change things? Just so all the listeners kind of have it in their head, neuroendocrine carcinoma...
should be thought of as a totally different disease. It is not a neuroendocrine tumor, and it's treated more like a small cell lung cancer than it is like any GI cancer. So it's given, you know, cisplatin, it's given... a lung cancer regimen basically for for chemo now the new thing is kind of immunotherapy but it's really not treated like a gi cancer because it's this very weird tumor that is very very aggressive i remember the medical oncologist who gave
us our lecture on this in fellowship said if i ever find out about you operating on a neuroendocrine carcinoma i'm going to find you and you know i can't remember what his threat was but he was basically like don't operate on these So, you know, every once in a while you may be in a situation where you're going to...
But I would argue it should always be after chemo. So these are very aggressive, and they tend to blow right through chemo, and the patients, unfortunately, do very poorly. And so if you ever get pathology back that's as neuroendocrine...
carcinoma, not neuroendocrine tumor, don't be confused. That is a wildly different disease that you as a surgeon probably have very little to offer that patient. And the other thing I would say is if you get a neuroendocrine tumor that is done by an inexperienced pathologist and the ki 67 is crazy high and they mentioned like some weird features you may want to send that out for expert pathologic review because they may be looking at a
neuroendocrine carcinoma and not knowing exactly what they're looking at yeah the other really weird one that i've come across is a mixed adenocarcinoma neuroendocrine tumor which is something that is really really really rare So definitely one that should be looked at by an expert pathologist. Generally very bad. You have two pathologies on one pathology report. Something bad is happening.
That concludes our case presentation today. Thanks, everyone, for listening. Just to review, we talked about the presentation of neuroendocrine tumors, key points of their workup, including what labs to and maybe not to order, as well as imaging studies. We talked about what a dotatate scan is. is and its relationship to PRRT as well as other medical therapies. And finally, we talked about operative management.
Key aspects reviewed here include careful running of the entirety of the small bowel and the ever-important mesenteric dissection of these tumors. We ended with some case variations including poorly differentiated tumors and neuroendocrine tumors in other areas such as the adenum and appendix. We're your surgical oncology team. Thanks for listening. And until next time, dominate the day.
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