I see in the NCCN recs for anal canal follow up that CT CAP and MRI abdomen/pelvis is recommended on top of the H and P, labs and anoscopy. Does anyone have any reason or data to think the MRI is necessary. We never did this in training and neither do my partners now. Comments or thoughts on need?
Anal Canal Follow Up
- Thread starter xrt123
- Start date
drewdog1973
Full Member
- Joined
- Nov 26, 2020
- Messages
- 299
- Reaction score
- 622
Not really. For staging sometimes it helps with target delineation, and if it wasn’t a very PET avid tumor to begin with, if there is suspicion for something during follow up, it may help. But not routinely, I don’t think.
- Joined
- Dec 17, 2007
- Messages
- 3,413
- Reaction score
- 4,444
This is an area with little evidence, unfortunately.
Where I practice, we follow up with anoscopy and do one "baseline" MRI at 6 months post radiochemotherapy. From there on guidelines are open.
Some call for a yearly MRI, some say just clinical examination/anoscopy.
Personally, I only do additional imaging after that "baseline" post-therapeutic MRI if:
a) the 6 months "baseline" MRI shows residual tumor and/or
b) there was initial nodal involvement.
So any patient with a T2N0 who's at CR after 6 months doesn't get any more imaging beyond that 6-months MRI.
Where I practice, we follow up with anoscopy and do one "baseline" MRI at 6 months post radiochemotherapy. From there on guidelines are open.
Some call for a yearly MRI, some say just clinical examination/anoscopy.
Personally, I only do additional imaging after that "baseline" post-therapeutic MRI if:
a) the 6 months "baseline" MRI shows residual tumor and/or
b) there was initial nodal involvement.
So any patient with a T2N0 who's at CR after 6 months doesn't get any more imaging beyond that 6-months MRI.
- Joined
- Oct 10, 2011
- Messages
- 8,639
- Reaction score
- 10,744
I don't use MRI for anal cancer at initial diagnosis, so I'm not really sure what I'd be looking for in a f/u MRI in anal cancer.
PET/CT at 3 months, then anoscopy every 6-12 months, with DRE + groins q3 months. Once yearly CT chest, although we'd consider adding on abdomen/pelvis too at that time.
PET/CT at 3 months, then anoscopy every 6-12 months, with DRE + groins q3 months. Once yearly CT chest, although we'd consider adding on abdomen/pelvis too at that time.
- Joined
- Sep 20, 2004
- Messages
- 11,782
- Reaction score
- 11,875
Reminds me of the time when another specialist mentioned getting an endorectal U/S for staging a new anal scc pt. Told them i already did my staging during the consult lol
There is some analogy to breast ca...
- For the usual breast ca s/p lumpectomy, chemo ---> RT, correct me if I am wrong but most medonc's do not order post-Tx imaging studies bc there is not much they can do in term of curative Rx.
So they wait until symptoms, if any, come up and order imaging studies accordingly. I believe this is what NCCN says in order to reduce health care cost from excessive imaging in the past post-Tx.
Back in the 1990s and 1990s, medonc's order routine bone scans, CT Chest/Abd/Pelvis every 6-12 months etc. etc., it was expensive and caused anxiety to the pts. It is no longer the case.
- Now back to the topic of anal ca, in my practice, it is almost akin to breast ca:
* At Dx, besides the usual CT, MRI of the pelvis, I order a PET-CT to look for distant mets (para-aortic LN, liver, lung, bone mets etc.), which may or may not change the Rx modality (chemo alone vs chemo, then chemo-RT etc. etc.).
* Post-Rx: you are looking for something you can salvage, in this case isolated anal persistent/recurrent disease, so the DRE is absolutely essential, and it should be done by the same radonc who knows the pt from day one. "Maybe" (yes maybe) and PET-CT post Tx for my curiosity than anything else (any distant mets). In the future if Immunotherapy drug(s) can make a difference then one might consider more imaging studies.
* Any you guys/girls know, groin or pelvic nodal failure is fatal, so in my follow-up clinic, I do a DRE and check the groins, and supraclav nodes and pray I don't feel any groin or supraclav LNs!!! Luckily I only had one isolated anal failure in ~ 100 anal ca pts I treated over the years.
* In 2021, AFAIK, only isolated anal failure is potentially curable by either further RT boost (EBRT vs brachy) or APR.
Anything else (groin, para-aortic, supraclav LN, liver, lung, bone met) is fatal...
Hopefully the young physician-scientists come up with something for recurrent disease in the future...
- For the usual breast ca s/p lumpectomy, chemo ---> RT, correct me if I am wrong but most medonc's do not order post-Tx imaging studies bc there is not much they can do in term of curative Rx.
So they wait until symptoms, if any, come up and order imaging studies accordingly. I believe this is what NCCN says in order to reduce health care cost from excessive imaging in the past post-Tx.
Back in the 1990s and 1990s, medonc's order routine bone scans, CT Chest/Abd/Pelvis every 6-12 months etc. etc., it was expensive and caused anxiety to the pts. It is no longer the case.
- Now back to the topic of anal ca, in my practice, it is almost akin to breast ca:
* At Dx, besides the usual CT, MRI of the pelvis, I order a PET-CT to look for distant mets (para-aortic LN, liver, lung, bone mets etc.), which may or may not change the Rx modality (chemo alone vs chemo, then chemo-RT etc. etc.).
* Post-Rx: you are looking for something you can salvage, in this case isolated anal persistent/recurrent disease, so the DRE is absolutely essential, and it should be done by the same radonc who knows the pt from day one. "Maybe" (yes maybe) and PET-CT post Tx for my curiosity than anything else (any distant mets). In the future if Immunotherapy drug(s) can make a difference then one might consider more imaging studies.
* Any you guys/girls know, groin or pelvic nodal failure is fatal, so in my follow-up clinic, I do a DRE and check the groins, and supraclav nodes and pray I don't feel any groin or supraclav LNs!!! Luckily I only had one isolated anal failure in ~ 100 anal ca pts I treated over the years.
* In 2021, AFAIK, only isolated anal failure is potentially curable by either further RT boost (EBRT vs brachy) or APR.
Anything else (groin, para-aortic, supraclav LN, liver, lung, bone met) is fatal...
Hopefully the young physician-scientists come up with something for recurrent disease in the future...
- Joined
- Dec 2, 2011
- Messages
- 1,495
- Reaction score
- 3,037
Usually not. The only time we do it is if the tumor extends higher into the rectum or had an extensive extraluminal component both of which can limit the utility of PE and endoscopy during follow up. Insurance companies don’t love serial PETs so it can be a good alternative.
- Joined
- Dec 17, 2007
- Messages
- 3,413
- Reaction score
- 4,444
One trial has looked into MRI for response evaluation in anal cancer with imaging at 3 and 6 months after RCT and showed very good results to rule out / confirm recurrent tumors (actually 100%).
pubmed.ncbi.nlm.nih.gov
It is a small trial, but it is what is often cited to justify MRI for response evaluation.
The assessment of local response using magnetic resonance imaging at 3- and 6-month post chemoradiotherapy in patients with anal cancer - PubMed
• Post-chemoradiotherapy MRI (3 and 6 months) helps local response assessment in ASCC. • The MRI-TRG system can be used reproducibly in patients with ASCC. • The TRG system facilitates patient selection for examination under anaesthesia and biopsy. • The use of MRI-TRG predicts for detection of...
pubmed.ncbi.nlm.nih.gov
Last edited:
- Joined
- Oct 10, 2011
- Messages
- 8,639
- Reaction score
- 10,744
I mean, lumpectomy pts all get f/u mammograms, but yes, most are not getting routine 3D imaging looking for mets.
What do you use an MRI for in anal cancer that a PET/CT does not get you at initial diagnosis? I'm genuinely interested in why anyone needs an MRI in anal cancer, because while MRI in rectal cancer can help with delineation of disease and is important for T-staging (and thus prognosis) and rectal cancer patients frequently do NOT get a PET/CT, the same benefit is not seen in Anal cancer patients, as staging is based on size, and in my practice, get a PET/CT 100% of the time.
In regards to bolded - Never say never to oligometastatic (anal) cancer - TBD if those patients are truly 'cured' but 4 out of 5 had > 1 year without recurrence, which isn't nothing! - Definitive Chemoradiation in Oligometastatic Squamous Cell Carcinoma of the Anal Canal
- Joined
- Apr 21, 2011
- Messages
- 3,627
- Reaction score
- 9,284
But the rectum and anus are the same thing, right?
- Joined
- Jul 14, 2020
- Messages
- 1,376
- Reaction score
- 4,166
I don't use MRI for anal ca. PET at 3 months is helpful if significant tumor at dx and PET avid at diagnosis. (PET response correlates to ultimate risk of recurrence and restaging CT and exams can be confusing).
I agree with @evilbooyaa that so much of what we do now is try to contribute in low metastatic burden patients, so why not do the annual systemic imaging for the first 3 years. Same principle as head and neck and both these populations pretty susceptible to lung CA as well.
I agree with @evilbooyaa that so much of what we do now is try to contribute in low metastatic burden patients, so why not do the annual systemic imaging for the first 3 years. Same principle as head and neck and both these populations pretty susceptible to lung CA as well.
- Joined
- Dec 2, 2011
- Messages
- 1,495
- Reaction score
- 3,037
MRI at diagnosis is useful for rectal cancer because it is still a primarily surgical disease and getting an accurate assessment of depth of invasion or MRF involvement can significantly affect upfront management. Unless you are talking about a teeny tiny anal cancer that might be a WLE candidate, they all get the same upfront treatment. I can't honestly tell you what an MRI would add to a PET-CT 99% of the time. These are by and large strongly PET-avid tumors and its not clear how modestly improving the soft tissue contrast would really change anything. The only exception that I can think off hand might be if you are worried about fistulous tracts- especially cutaneous fistulas. They can have malignant involvement that is not well visualized on PET.
In follow up I do think MRIs can be helpful in place of PET-scans for patients with tumors that had extraluminal extension or extended to cranial to be well visualized on anoscopy. Also not a very common situation. I can only think of 2 anal patients I have ever followed with MRIs post-treatment.
