How do you manage early stage anal or anal margin cancer that is locally excised with negative but close margins when going back for wider margins would require an APR?

I've seen this scenario several times when a patient has an excisional biopsy (the surgeon doesn't think it is cancer) and leaves behind a positive or close margin. After properly staging the patient with pelvic MRI, I typically recommend adjuvant chemoradiation since they are at risk for recurrence. That being said, a couple of caveats:

1. I do have 2 patients that I have been watching under close surveillance now for >2 years that have not recurred. I'm not sure close surveillance with initiation of treatment at recurrence would be any worse than upfront adjuvant therapy, and we might spare some patients the morbidity of treatment that don't need it. Since CRT is so effective, the patients can be easily salvaged.

2. It's not clear chemora...

Also relevant to this discussion is the current U.K. ACT3 study which will generate some prospective data in this group in the following schema:

”ACT3: a prospective non-randomised phase II trial which will evaluate a treatment plan in patients with early, small tumours who have undergone surgery (local excision). Patients with no tumour cells close to the cut edge of the removed tissue (margins >1mm) have no further treatment, and those with tumour cells close to the cut edge (margins ≤1mm) receive additional lower-dose CRT (41.4Gy in 23 fractions). We aim to determine whether this treatment strategy results in acceptably low rates of the cancer coming back.”

These are important cases to discuss in a multidisciplinary setting. I agree with everything previously posted by @Dr. First Last, @Dr. First Last, @Dr. First Last, and @Dr. First Last. We are still waiting for the results of the U.K. ACT3 study. @Dr. First Last’s EA2182 DECREASE (NCT04166318) study will also help provide prospective evidence about radiation and chemotherapy dosing for early stage anal cancer. Like Dr. Buckstein, I typically offer chemoradiation for these patients but agree that it is unclear if there is a benefit over radiation alone. We did investigate the role of radiation therapy alone vs. chemoradiation in stage I anal cancer patients using the NCDB and found that chemoradiation was associated with improved overall sur...

An alternative option is observation for everyone with small (<1cm excised) tumors when the margins are negative. Patients with positive margins can also be followed because of the overall favorable biology. This is a locoregional disease and the salvage option is as effective as initial treatment because the DM rate is so low. There is an extremely wide window of opportunity to salvage these patients, follow-up can be digital rectal exam only in most cases.

Especially in female patients radiation affects sexual function. If I do opt for post excision treatment, I consider local only treatment with a vaginal dilator during simulation to spare the introitis. Particularly for small T1's and micro invasive disease, the inguinal failure rate is...