Anal CA recurrence in vulva

[Joinedsolate]

Hey everyone,

We have two cases of anal cancer (both T2N3) treated w/ IMRT that recurred in the vulva. The genitals were contoured as an OAR but in light of these 2 cases we're considering treating the vulva for future ACC patients, especially with bulky nodes. I did a lit review and could not find any similar reports. Has anyone seen this before? All thoughts are welcome.

Thanks!

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[medgator]

Similar pathogenesis with HPV and similar patterns of spread to the groin. Haven't seen it personally, interesting

 

[Palex80]

We have two cases on anal cancer recurring in the skin >5 cm from the anal verge.
Skin >5cm from the anal verge is not within the CTV according to current recommendation, yet these patients recurred in their ...buttocks.

I think the cases you presented show the problems we may be facing with IMRT in this disease. With standard field arrangements the ap/pa fields treated the entire vulva and most of the buttocks to doses over 40 Gy in most cases, nowadays doses with IMRT in these areas are considerably lower. And with anal cancer being a "skin" disease, subcutaneous lymphovascular spread can be an issue.
It's a bit like incidental dose to contralateral nodes when you are treating NSCLC with 3D vs. IMRT. You can nowadays spare the esophagus with IMRT, leading to less high dose in the contralateral mediastinum than you had with 3D field arrangements.

 

[seper]

I personally treated a pt who had a vulvar recurrence of anal canal adenoCa. Her initial disease was locally advanced with visible spread along anal margin askin. For T1-T2 tumors though, I continue to treat labia and pubis as OAR's. V