Welcome to First Incision, the podcast about preparing for the General Surgery Fellowship exam. I'm your host, Amanda Nikolic. Hello and welcome back to First Incision. Let's get straight into it with our team timeout. Our patient today is still the colorectal module from the general surgical curriculum. And our operational, the topic we're going to be touching on today is the treatment of rectal cancer.
As I mentioned in our last episode on colon cancer treatment, rectal cancer is treated a little bit differently. And when we're talking about the treatment of rectal cancer, we need to remember that we're talking about tumors that are... abutting or below the anterior peritoneal reflection. And this is something that can be determined usually based on the MRI pelvis. This is an important distinction because tumors that are above this or higher rectal tumors are managed as per colonic tumors.
The decision making around treatment of rectal cancer is super complex. We had a shoot the other day with one of the senior colorectal surgeons at my hospital who said the same thing. So I don't think we're expected to know the answer. to all of this in the exam. I think even the evidence is not quite back on some of these decision points. But I'll talk about the main treatment modalities for rectal cancer, as well as some sort of general considerations or things that should...
be factored into your decision making around treatment. And in general, these patients should be discussed at an MDT. So as with most of the cancers that we've discussed, the treatments include neoadjuvant, and in rectal cancer, that's neoadjuvant chemotherapy and radiotherapy, surgery, and adjuvant.
The sequence of treatment in patients is controversial and not fully addressed by current available data and really should be guided by a number of factors, which include... presence or absence of symptoms from the primary tumour, whether there is metastatic disease, whether the metastatic disease is potentially resectable, and also a little bit by your institution preferences.
So the first topic I was going to talk about is neoadjuvant treatment. So the first question is, why should we give chemoradiotherapy neoadjuvantly, so before surgery for rectal cancer? And there was a seminal trial, which was a German CAO trial in 2004 that compared preoperative to postoperative chemoradiotherapy in rectal cancer. And this demonstrated reduced local.
recurrence rate of 6% versus 13% and lower acute and long-term toxicity with neoadjuvant treatment. So that is why we give it neoadjuvantly in rectal cancer.
Another way of thinking about it that I really like, I heard the other day, is that we give it neoadjuvantly because the rectum and the tumor and the mesorectum is in place and so it can get given good. But that once the... rectum has been resected, the small bowel will fall down into the pelvis and you get more toxicity from irradiating the small bowel whilst trying to improve local control postoperatively than you do preoperatively.
The indications for neoadjuvant treatment are a little bit foggy. In general, it's pretty standard for most stage 2 and 3 rectal cancers. So clearly for patients who have a large tumor, T3 or T4. If it's node positive on imaging, especially if it's close to the circumferential resection margin or to the mesorectal fascia, but there really isn't any hard and fast rules. So for example, you might have a T3 tumor.
with no obvious nodal disease, but maybe some obstructive symptoms, in which case you might take this patient straight to theta. And there may be patients who are sort of an early T3 with less than one millimeter extension from the bowel wall. no nodes, no threatened circumferential resection margin, and in some institutions, those patients would go straight to TME. Patients who have metastatic disease are also considered for neoadjuvant treatment. So these are patients who might have...
resectable liver or lung metastases. And these patients may have neoadjuvant chemoradiotherapy or total chemotherapy in order to preoperatively... treat their metastatic disease prior to even resection of the primary. This is sort of a newer concept. And in patients with borderline resectable disease, they may also require neoadjuvant treatment to try and downstage the disease. And that could include borderline resectable primary tumors or even borderline resectable metastases.
depend on the tumor, the size, the circumferential resection margin, whether there's any nodal or metastatic disease, and obviously a discussion at the MDT. So in terms of what we give for neoadjuvant chemoradiotherapy in rectal cancer, if we ignore total neoadjuvant treatment for a moment and just talk about standard treatment for rectal cancer, typically this will involve... chemotherapy as well as either short or long course radiotherapy. And just a note here, we give neoadjuvant...
chemoradiotherapy in rectal cancer, remember I mentioned this earlier, to improve local control or to reduce local recurrence. There's no evidence that this improves overall survival. Other indications for giving neoadjuvant chemoradiotherapy is to try to downstage the tumour and this is especially relevant if you have a threatened or involved circumferential resection margin because getting a clear TME with no involvement of the CRM is again important.
for local control. About 20% of patients will get a complete pathological response to a neoadjuvant chemoradiotherapy in rectal cancer. And also another reason may be to try and enable sphincter-preserving surgery for a low rectal cancer. So just briefly mentioning neoadjuvant chemotherapy, the agents mostly used are five... FU or 5-fluororacil, which is used primary as a radiosensitizer. So to improve the effect of the radiotherapy. So short course radiotherapy.
is 25 gray given over five daily fractions over five days. And there was a 2015 systematic review and meta-analysis that showed No difference in local recurrence or overall survival when considering the shorter course to the longer course. There's a few different trials that have looked at short course versus long course or short courses versus surgery alone. And this includes the Swedish rectal cancer trial and the Dutch.
TME trial, which both showed improved local recurrence with some increased in post-operative wound complications in the setting of the pelvic radiation. There's not really a lot of short course given in Australia. In other countries, it's given a lot more commonly. But in Australia, more commonly, we give long course radiotherapy. And this is usually given as 50 grays, which is given as 1.8 gray fractions over 28 fractions. And again, usually combined with 5-FU or capsidabine.
The longer course has higher rates of tumor downsizing and complete pathological response and definitely indicated over short course radiotherapy in patients with a large tumor, a T4 tumor. If they have nodal disease in the mesorectum and if the tumor is close to the mesorectal fascia or there is a threatened margin there, in which case you, like I mentioned, would be more likely to give the longer course. There's definitely downsides to giving radiotherapy.
It does make surgery slightly more difficult technically because of the scarring and increases your risk of postoperative wound complications. In addition, you can get sexual dysfunction. proctitis, healing difficulties, and endarteritis obliterans as potential side effects to radiotherapy.
The optimal timing of surgery after neoadjuvant treatment is another thing to consider. It used to be relatively short, sort of between four and six weeks, but the optimal time now has been stretched out a little bit. probably between eight and 10 weeks. In general, between six and 12 weeks is acceptable. And you may want to wait slightly longer if you have a large tumor you're trying to downsize.
I've asked a couple of consultants recently as well about whether you need to restage patients after neoadjuvant chemoradiotherapy. In general, it sounds like some people do it all the time. Some people... don't do it at all and some people do it selectively. If you're going to restage, then you'd usually restage around the eight-week mark because you want to make sure that the neoadjuvant chemo-ready therapy has had time to work and you'd be aiming to operate between the eight and 12-week mark.
In the exam, I think my approach is going to say that I routinely restage everyone. Restaging may demonstrate progressive disease, may demonstrate liver metastasis or presence of other metastatic disease, which may change what you do. and also restaging and reassessing your tumour and the involvement of any local structures or encroachment onto the...
circumferential resection margin may change your operative approach. So it'd be good to restage and reassess what you have after the neoadjuvant treatment to then guide further planning. Another emerging thing that I should probably mention when talking about neoadjuvant chemoradiotherapy in rectal cancer is the concept of the watch and wait approach. This is quite a controversial...
a new approach which has mostly come out of South America. As I mentioned, there's about 20% of patients that will have a complete pathological response. And so patients would have a rectal resection and the final pathology specimen would not show any viable tumour cells. Surgeons started asking the question whether or not we do have to do a resection in patients who have a complete pathological response. For some patients who...
It looks clinically and radiologically like there's been a complete response to the neoadjuvant chemoradiotherapy. And in the trials, they did give slightly more chemotherapy and radiotherapy than what I just discussed. then these patients would, instead of having a rectal resection, undergo intense surveillance with three monthly... investigation with a clinical examination, rigid sigmoidoscopy, potentially biopsies, MRI scan, and sometimes CT and PET scan.
Meta-analysis of the data from this approach has demonstrated that there definitely is a higher risk of local recurrence with watch and wait compared to those patients that have surgery. But proponents of this approach say that if you watch closely enough and pick up the recurrence, early enough that the disease is local and often confined to the mesorectum and so if you pick it up early you can resect it and therefore that they're salvageable with a later operation.
Obviously, people who are against this approach say that there's not enough data to support this approach as yet. And definitely the Australian Cancer Council recommendations is that for patients who have a complete response, they should undergo resection and that watch and wait is only... recommended or considered if patients decline surgery.
One of the surgeons that I talked to recently said that given this is out there and there is data on this, that he always discusses this with his patients. Definitely these patients should be discussed at an MDT. And if they decline surgery, they do need that intensive surveillance protocol. I'll briefly touch on total neoadjuvant therapy, which is this new concept of giving patients complete neoadjuvant chemotherapy regimes as well as chemoradiotherapy so they won't need any adjuvant treatment.
This wouldn't, I say, be a routine practice in Australia at the moment, but there is a population that you may consider this for, and that would be patients who present with synchronous metastatic disease. The neoadjuvant chemoradiotherapy we give for rectal cancer only uses 5-FU or capsidabine as a radiosensitizer and standard chemotherapy regimes for...
Rectal cancer and colon cancer include things like Folfox or Folfirinox. So patients aren't being given the, I guess, metastatic chemotherapy protocol to treat the metastatic disease. So in these patients, you might consider... treating their rectal cancer with neoadjuvant chemoradiotherapy, as well as giving them a course of chemotherapy in order to treat their micrometastatic disease. Again, there's people who are...
for and against this. And there's definitely people that want this to be standard of care in patients with resectable rectal cancers and even no metastases. But I don't think this has really been well enough established or well enough research to have a clear answer about. But I think in the exam, that population where you have metastatic disease at diagnosis could be the sort of patient you might mention total neoadjuvant therapy for.
The other thing that's not really decided on yet, I guess, is whether or not to give chemoradiation followed by systemic chemotherapy or whether to give systemic chemotherapy followed by chemoradiation. And there are a few trials out there at the moment that are trying to answer that question. So that's another thing to watch out for. The last thing that I'll mention is the concept of definitive chemoradiotherapy for rectal cancer.
There is a line in the Cancer Council guidelines that says in patients who refuse or who are unable to tolerate surgery, definitive radiation treatment with or without chemotherapy may be considered as a potentially curative.
approach. There is no randomized control data to support this, but I guess if you're given a patient in the exam who's significantly comorbid or elderly, but who may be able to tolerate chemoradiotherapy, There is a small percentage of patients who will have a complete pathological response, so they could be considered for definitive chemoradiotherapy and then palliative treatment if that fails.
Moving on now to adjuvant chemotherapy. The aims of adjuvant chemotherapy in rectal cancer treatment is to eliminate micrometastatic disease. to reduce their risk of recurrence and improve their recurrence-free and overall survival. Indications for adjuvant chemotherapy in rectal cancer is not... very well supported by the literature, but in general, patients with stage two and three rectal cancers will be referred for adjuvant chemotherapy. Typically, this is six months of
oxaliplatin, and 5-FU chemo, which is based on the Mosaic and the NSABPC7 trial. Patients who are initially staged as stage 1 rectal cancer and go... directly to surgery who are subsequently upstaged on their histopathology report, they may then be considered for adjuvant treatment, which could also include radiotherapy treatment as well as 5-FU.
Patients who have metastatic disease, especially if they have their metastatic disease resected such as liver or lung metastases, should receive further adjuvant treatment to reduce the chance of them developing further local or systemic. recurrences. Another thing it's probably worth just being aware of is that there's currently trials into circulating tumor DNA and how the presence of circulating tumor DNA after a section confers a higher risk of our local...
and systemic recurrence. So there's the DYNAMIC and the DYNAMIC-2 trial, which is recruiting at the moment, which looks at patients who have circulating tumor DNA postoperatively and is... Answering the question about whether these patients would benefit from adjuvant chemotherapy as well. So that's something interesting to keep an eye on.
Now it's time to talk a little bit about surgery for rectal cancer. In general, there are a few options which will depend on the size of the primary tumor, the depth of its invasion through the wall. the location of the tumour, as well as patient's fitness for surgery. So to start with... There are local excision options. This sort of goes along the same lines as an ESD type procedure for esophageal and gastric cancers. So this is the equivalent sort of local resection options for rectal cancer.
cancer. Local excision is only indicated in the setting of TIS, a tumor in situ, or T1 tumors that are accessible from the anal canal. This is a little bit controversial. There are slightly higher recurrent rates than for resection of the cancer. There's an issue because you're not going to be removing the mesorectal lymph nodes, which is obviously an important factor when looking at rectal cancer. And in addition...
Local resection can make subsequent salvage surgery more difficult due to disruption of the mesorectum. But in general, the options include a trans-anal excision. a transanal endoscopic microsurgery excision, which is a TEMS, or a transanal minimally invasive surgery excision, which is a TAMIS. All of these approaches involve excising the... early tumour and typically this is a full thickness excision down to the perirectal fat and then closure of the defect with an absorbable suture.
The different approaches basically relate to the equipment used in order to perform the excision. This approach can only be used on small tumors, obviously, as you need to be able to close the defect in the wall. And also can only be used on tumors that are below the peritoneal reflection. Otherwise, if you're performing a full thickness excision, you leave a perforation there. Although...
There are some centres that would advocate for a combined trans-anal excision and then laparoscopic suturing and closure of the area. Transanal excision is basically done transanally with just a normal anal retractor and you basically use a diathermy to perform your incision and close with normal instruments.
A TEMS procedure uses TEMS equipment, which is fitted to the operating table. And depending on the location of the lesion, the patient may need to be proned if it's an anterior lesion. And these are usually used for... lesions that are sort of mid and upper rectum that can't be accessed by the transanal approach. The transanal approach will only reach where you can see, so usually sort of six to eight centimetres is the maximum distance. The Thames approach uses laparoscopic equipment.
as well as insufflation to be able to expose the operative field. And again, uses the same technique with a full thickness excision and closure of the defect with a running absorbable suture. TAMIS is similar to TEMS but it uses standard laparoscopic equipment and you need an assistant to hold the camera and middle rectal lesions are most suited to this technique.
Like I said, though, these are limited to only very early tumors as the risk of nodal involvement increases as the stage of the tumor increases. So in general, T1... Rectal adenocarcinoma have lymph node metastasis rates from 0% to 13%. And if you divide T1 tumors into three groups, either with slight submucosal invasion, an intermediate group, or inter... submucosal invasion to the deep aspect of the submucosa, you can also have increasing rates of lymph node metastases.
In general, when we talk about rectal cancer though, we talk about elective resection with surgical excision really being the mainstay of treatment for colorectal cancer. The type of operation depends on a few factors including the location of the primary cancer, whether or not there are any other cancers or lesions in the colon that need to be removed as well as the T stage of the cancer with exonterations considered depending on if other structures are involved.
I cannot possibly go further in a rectal cancer episode without touching on the total mesorectal excision or TME. When we talk about total mesorectal excision or TME, we're talking about excision of the mesorectum on block with dissection outside of the mesorectal fascia, which results in removal of the regional lymph nodes. And there is robust data that a total meslorectal excision reduces loco-regional recurrence by two-thirds. So when this was established, it really was...
groundbreaking and is now the standard of care approach for rectal cancer surgery. In terms of other things to be aware of for rectal cancer, this is obviously an oncological... So even though you're removing the rectum, they still recommend high ligation of the inferior mesenteric artery below the origin of the left colic.
Different types of rectal operations, depending on the location of the tumor, could include an abdominoperineal resection for a very low rectal cancer. This involves removing the anus and forming an end colostomy. And this would be indicated if you cannot get a distance of at least a centimeter below the cancer, that would therefore mean that you couldn't preserve the sphincter complex.
In addition, if there is invasion of the synctor complex by the cancer, if the anal verge or the puborectalis muscle... involved, then these would also be indications for an abdominoperineal resection or an APR. Other types of operations include an ultra-low anterior resection. And this is where the join is in the lowest 5 centimetres of the rectum. A low anterior resection, which is where the join is between 5 to 10 centimetres from the anal verge.
and an anterior resection is where the joint is more than 10 centimetres from the anal verge. If there is involvement of other pelvic structures, then a exonteration could be considered. This would be in situations where you have quite an advanced tumor or a locally recurrent tumor. and can also be considered when the MRI provides evidence that there may be extension beyond the circumferential resection margin. There are different types of exoneration that can be performed.
A total exoneration includes all of the pelvic organs, including the back, bladder, rectum, anus, supportive musculature, ligaments, and reproductive organs. You can also consider a posterior. exonteration, which involves the rectum and can involve the sacrum, and anterior exonteration, which includes removal of reproductive organs and bladder or combinations of these.
The key points of surgery to remove erectile cancer would be starting with an abdominal exploration looking for metastatic disease. mobilization of the left colon and splenic flexure in order to obtain length to bring down your proximal bowel.
You want to take the inferior mesenteric artery as high as you can, both for oncological reasons as well as to allow mobilization of the descending colon. And once you've divided the IMA, the colon... is now just on the imv which you once you've mobilized the colon and have swung it down want to divide somewhere below the pancreas. You don't want to divide this right on the pancreas because if it bleeds and disappears behind the pancreas, it's difficult to find.
Dividing it high will give you hopefully enough length to be able to pull the bowel down to at least the level of the pubic symphysis. The rectal dissection should be performed with a total mesorectal excision. with care taken to avoid damage to seminal vesicles and prostate in men and the posterior wall of the vagina in women. In addition, posteriorly to the rectum, care needs to be taken to avoid injury to the pelvic.
autonomic nerves. These include the superior hypogastric nerves as they enter into the pelvis above the sacral promontory and the nervi erigentes which are along the pelvic side walls which travel to the inferior hypogastric plexus. Mobilization of the rectum should be continued to below the level of the tumor. With an aim for 2cm or greater, however, depending on how distal it is and whether the patient's had neoadjuvant chemotherapy, a 1cm margin may be acceptable.
A tension-free, well-vascularized anastomosis should be performed, and for all ultra-lows and for some low anterior resections. Especially if the patient has had neoadjuvant radiotherapy, it's suggested that a diverting loop ileostomy be performed. as this is demonstrated, to reduce the complications of anastomotic leak, which has much higher incidence in lower rectal anastomosis.
In patients who have an intraperitoneal anastomosis, such as those undergoing an anterior resection, you don't need to perform a covering loop ileostomy. As long as the patient's general condition is good, the local conditions of the bowel are good and you're happy with that. your anastomosis is healthy. You may be asked in the exam about a colonic pouch.
And having talked to a couple of colorectal surgeons, I think you just need to know a little bit about the pros and cons because the jury really is out. There's a lot of different opinions. For me in the exam, I think I'm going to say no, that I don't do a colonic pouch. The reason being that there's no functional benefit at 12 months. It adds obviously time to the procedure and also requires further length of bowel which may influence your ability to do a tension-free anastomosis.
Some of the potential pros to a clonic pouch, though, is that there may be a slightly lower leak rate, which is in some of the literature, but this is obviously difficult to prove given nearly all patients have diverting stomas.
and that maybe they initially have better rectal function, but at 12 months that they are equal. In terms of the... ileostomy you would usually reverse this after adjuvant therapy if they're going to have some and if not after three months before you close the stoma you need to make sure that the patient is well and nutritionally replete
that the anastomosis has healed well, and this is typically confirmed with a PR exam if it's palpable, as well as with a gastrographin enema and sometimes a sigmoidoscopy, but that's a little controversial. Some people do that and some people don't. And once you've proven that your osmosis is healed in the patient as well, then that's the time to reverse their ileostomy.
I just briefly want to talk about the options or what you might do if you come up against a obstructing or a near obstructing rectal cancer, because this has its own special discussion points. The options include...
resecting the cancer up front, which obviously loses the benefits of neoadjuvant chemoradiotherapy and the opportunity to perform that, or to perform a loop colostomy in order to decompress the patient and then provide neoadjuvant chemoradiotherapy and then subsequently perform your dissection.
thing here is that you want to do a loop colostomy because if you do an end colostomy you then have a short segment of closed loop between your stapled end of rectum and the cancer which can lead to a stump blowout so the key here is to do a loop colostomy Some people may also suggest doing a ileostomy, but the obvious problem here is if they don't have an incompetent ileocecal valve, then they can get a sequel perforation due to, again, a closed loop obstruction.
If you do have a patient who has an obstructing or near-obstructing cancer that maybe is a T3, there may not be any nodal disease, then you could potentially talk about doing a primary resection, although I think this probably isn't ideal for the exam. you do get into a situation where you're doing a resection and an anastomosis maybe for a colonic cancer or upper rectal cancer for example then a key thing to consider is that there's going to be a large column
of stool proximal to your anastomosis, which may impair healing of that anastomosis. And those are the patients where you would consider a colonic lavage to clean out the colon. And a couple of key points of this procedure is that you need to mobilize both flexures, otherwise the fluid will just fill up in one side.
Typically, it's done by incising the appendix and inserting a Foley catheter through the appendix and flushing with a lot of normal saline. Also, if you have sufficient length in a skinny patient, you may just be able to flop the distal end. out of the wound and off the table to collect the effluent. But if you can't do that, then you can use sterile anesthetic tubing and tie that into the distal aspect of the bowel to then direct the effluent off the table.
The question about whether or not to perform laparoscopic or open surgery for rectal surgery is not quite as straightforward as with colon cancer surgery. In general, the pelvis is a fixed bony ring and particularly in males, this can be quite narrow and leave very limited space for dissection. The mesorectum, which needs to be removed with the rectum, can be quite bulky, especially in obese patients. And laparoscopic instruments...
can cause difficulty with long instruments, angulation, and traction on the mesorectum, which can compromise the TME. There's been a number of large trials, including the ALICAR trial and the ACOSOG Z6051 trial, which failed to find non-inferiority in laparoscopic surgery for rectal cancer. Although I have seen it done, I think for the exam, open operation would be preferred for a rectal dissection if you get asked the question.
Also, just briefly on margins, I know I've discussed at least a one centimetre distal margin for low rectal cancers, but definitely a two centimetre margin is preferred if this is possible, especially if the patient hasn't had neoadjuvant. treatment. And in regards to the circumferential resection margin, a margin of at least two millimeters.
has a reduced local recurrence rates compared to margins less than two millimeters. And margins that are less than one millimeter have increased risk of distant metastatic disease. So you want to be getting a margin of at least two millimeters. So I think that's all I have to talk about for rectal cancer. Like I said, it's pretty complex, but hopefully this has given you a bit of an overview and some tools to be able to talk about different potential scenarios that you may encounter.
There is an absolutely stellar guest coming onto the podcast next week to talk to us about colon and rectal cancer, as well as a few other things. So make sure you check out that episode. Once again, remember to rate, review and subscribe so others can find this podcast. send us a message at firstincisionpodcast at gmail.com or follow us on Instagram at firstincision. Happy studying!