PT3N0 rectal cancer

[Ray D. Ayshun]

I have a patient who had a cT2N0 and barely pT3N0 high rectal cancer. She's young, as in 50s, but I'm looking for the evidence to offer her both supporting and opposing post op rt. As in the nuances inside the pT3 population. We kinda started this discussion in a separate thread, and there's a very short mention of this on mednet, where dr minsky, I believe, supports observation in some particular case, which seemed to be based upon intuition and experience. I don't have enough of the latter to fall back on, and the former is telling me there is a good path to observation here as it's high and perhaps more easily salvageable. In any case, I'd prefer to give the patient the best evidence and wondering if anyone knows of anything re recurrence risks based on path findings, location etc in the modern staging and surgical era.

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[Palex80]

We very often simply observe pT3 pN0 with wide margins.
There is no clear evidence that all pT3 pN0 patients "need" adjuvant RT after optimal TME.

The German guidelines for instance recommend adjuvant radiochemotherapy for pT3 pN0 only in cases of close margins, suboptimal TME quality (as defined by the pathologist) and a tumor in the distal part of the rectum.
I am not aware why the put the distal part of the rectum as a criterium, probably it is an extrapolation of data from the neoadjuvant trials (for instance the Australia/New Zealand trial).

 

[ramsesthenice]

I have a patient who had a cT2N0 and barely pT3N0 high rectal cancer. She's young, as in 50s, but I'm looking for the evidence to offer her both supporting and opposing post op rt. As in the nuances inside the pT3 population. We kinda started this discussion in a separate thread, and there's a very short mention of this on mednet, where dr minsky, I believe, supports observation in some particular case, which seemed to be based upon intuition and experience. I don't have enough of the latter to fall back on, and the former is telling me there is a good path to observation here as it's high and perhaps more easily salvageable. In any case, I'd prefer to give the patient the best evidence and wondering if anyone knows of anything re recurrence risks based on path findings, location etc in the modern staging and surgical era.

You have 3 options: observation, RT, or chemo. I would personally favor observation or chemo. I think that prospect shows in the neoadjuvant setting chemo is probably as good as RT for these patients. Same should apply for post op. I hate doing post op RT. Long term LAR type symptoms are a big problem. I personally wouldn’t do it for a person with negative nodes and margins.

 

[RADONC4285]

 

[communitydoc13]

I've never found very meaningful data on this. I've seen series where age, number of lymph nodes dissected, proximal vs distal and grade are all used to assess benefit and there is a very misleading National Cancer Database study out there where they infer a benefit for adjuvant chemo but not RT in this population. I think this paper is basically useless. I feel confident that proximal vs distal location makes a difference.

For more proximal tumors, I typically discuss with surgeon whether tumor entirely below peritoneal reflection or not. If borderline or significant tumor above peritoneal reflection, I don't treat.

I have seen in pelvic recurrences for pT3N0 disease and almost always further out than 3-4 years. I think a little bit like ER+ breast cancer, looking at short interval local control is a bit misleading.

 

[OTN]

I usually recommend no RT in high pT3N0 tumors.

 

[Ray D. Ayshun]

I don't disagree with what's been said. The issue is local expectation. What's been done here more or less, and in turn, what's required to do differently. Perhaps the NCCN is enough "evidence," but just wondering if there have been any retrospective studies, beyond this 2mm invasion criterion.

Tumor went below peritoneal reflection, so a true rectal cancer.

She's doing cape/ox, so technically that requirement has been met wrt NCCN recs.

 

[communitydoc13]

just wondering if there have been any retrospective studies, beyond this 2mm invasion criterion.

Here are some. Tumor location as an indication for adjuvant radiotherapy in pT3N0 rectal cancer after surgery

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doi.org

 

[scarbrtj]

I have a patient who had a cT2N0 and barely pT3N0 high rectal cancer. She's young, as in 50s, but I'm looking for the evidence to offer her both supporting and opposing post op rt. As in the nuances inside the pT3 population. We kinda started this discussion in a separate thread, and there's a very short mention of this on mednet, where dr minsky, I believe, supports observation in some particular case, which seemed to be based upon intuition and experience. I don't have enough of the latter to fall back on, and the former is telling me there is a good path to observation here as it's high and perhaps more easily salvageable. In any case, I'd prefer to give the patient the best evidence and wondering if anyone knows of anything re recurrence risks based on path findings, location etc in the modern staging and surgical era.

What would others do with a high peri-rectal nodal recurrence (very strongly PET positive, growth by CT over time) about 15 months after surgery in a case exactly like this (ie a high, run of the mill pT3)? I'm asking because I am now treating such a patient. And how would one's approach differ if the patient refused anything invasive (ie biopsy or surgery).

 

[ramsesthenice]

What would others do with a high peri-rectal nodal recurrence (very strongly PET positive, growth by CT over time) about 15 months after surgery in a case exactly like this (ie a high, run of the mill pT3)? I'm asking because I am now treating such a patient. And how would one's approach differ if the patient refused anything invasive (ie biopsy or surgery).

I have not decided how I feel about these situations. The older post op trials did standard 3 field pelvic RT post op. But, in this setting the pelvis is no longer anatomically confined. So does it still make sense? If on scope and MRI the anastomosis is ok do you need to treat the pull through? I’m not sure we know the answer.

At this point, I think treating the anastomosis makes sense because it would be a little tricky if they failed there later and you had to come back later. A reasonable approach would be to use IMRT to the nodes and anastomosis if you didn’t want to treat a standard 3 field.

Now let’s talk about the node. Is it resectable? And does it need to be resected? If it’s not right on bowel and you can boost it up to a BED > 100 with an SIB you may not need surgery. But if it’s easily resectable prep nodal RT with a limited resection is reasonable too.

 

[Palex80]

What would others do with a high peri-rectal nodal recurrence (very strongly PET positive, growth by CT over time) about 15 months after surgery in a case exactly like this (ie a high, run of the mill pT3)? I'm asking because I am now treating such a patient. And how would one's approach differ if the patient refused anything invasive (ie biopsy or surgery).

RT + chemo as neoadjuvant therapy. If the patient refuses surgery, then radical RT + chemo.

 

[Mandelin Rain]

I'd probably try to SIB the node in the case of non-operative approach.

Will be tough to localize daily though.