Groin SCC Unknown Primary

[Haybrant]

Got a 68 yo man with left groin SCC with unknown primary, presented with a 3.5 cm inguinal node he could feel. Underwent quite exhaustive workup to find a primary but nothing found. 4 years ago underwent shave biopsy and freezing of a left thigh SCC that was well differentiated, nothing there now. Underwent left inguinal resection and obturator dissection had 31/36 nodes positive + ECE (4/4 obturators were positive). Most of these were occult bc he only had 2 nodes active on preop PET. GI did another anoscopy didn't see anything, urology/derm sees no e/o penile disease. Did another PET at time of sim, still nothing to suggest a primary.

Curious your guys thoughts on RT field and doses now. Hes being quite resistant to chemo although I see a clear rationale here. Thank you

---

Members don't see this ad.

 

[BobbyHeenan]

I just last week saw a very similar case, except my guy was 70 with a 3.5 cm inguinal node (solitary node on CT and PET, no others abnormal) that was excised with gross total resection but with ECE. He's had some post-op wound problems requiring IV antibiotics and a superficial wound clean out, so surg onc doesn't want to take him back for a full dissection.

My patient has had CTs, PET, derm consult/exam, sigmoidoscopy/anoscopy, and HIV testing. All negative. I thoroughly examined his skin, perineum, penis, scrotum, DRE etc and all normal.

I was planning on treating his inguinofemorals and external iliacs to about 45-50 with a boost of the operative site to about 60-66. He is not getting concurrent chemo (I thought med onc may give radiosensitizing cis, but they opted not to). I too am open to suggestions, as I read and studied up on the case and didn't see a strong reason to be real dogmatic about it.

 

[OTN]

I just last week saw a very similar case, except my guy was 70 with a 3.5 cm inguinal node (solitary node on CT and PET, no others abnormal) that was excised with gross total resection but with ECE. He's had some post-op wound problems requiring IV antibiotics and a superficial wound clean out, so surg onc doesn't want to take him back for a full dissection.

My patient has had CTs, PET, derm consult/exam, sigmoidoscopy/anoscopy, and HIV testing. All negative. I thoroughly examined his skin, perineum, penis, scrotum, DRE etc and all normal.

I was planning on treating his inguinofemorals and external iliacs to about 45-50 with a boost of the operative site to about 60-66. He is not getting concurrent chemo (I thought med onc may give radiosensitizing cis, but they opted not to). I too am open to suggestions, as I read and studied up on the case and didn't see a strong reason to be real dogmatic about it.

That's more or less what I would do. I don't think it would be unreasonable to consider concurrent cisplatin, given the ECE, but obviously it's a data-free zone.

 

[seper]

4 years later, I would not treat the primary site. Just involved nodal regions + 1 echelon higher. 55.8 Gy to areas of ECE if small bowel allows. Good case

 

[Haybrant]

thanks guys all very helpful. His obturators were involved, I was also going to include internal iliacs as well because of this. I thought I could take everything to 45 then boost the area of highest concern which is a pretty generous area of the inguinals to 60-66. Fortunately Im ok with bowel though I suspect this will crush the femoral head. Should the obturators go higher?

 

[Neuronix]

No right answer.

I'd check p16 staining.

Generally, if positive I treat like an anal cancer -- same fields, RT, chemo (RTOG 0529)
Generally, if negative I treat like a skin cancer -- basically what BobbyHeenan said +cisplatin or cetuximab for +ECE.

 

[BobbyHeenan]

No right answer.

I'd check p16 staining.

Generally, if positive I treat like an anal cancer -- same fields, RT, chemo (RTOG 0529)
Generally, if negative I treat like a skin cancer -- basically what BobbyHeenan said +cisplatin or cetuximab for +ECE.

....So my patient ended up being p16 positive, keratinizing squamous cell on the groin lymph node, but his anoscopy/ proctoscopy are normal. Penile exam normal as well.

I'm leaning toward treating him like RTOG 0529 (though on this trial if node + the primary site is taken to 54, I would probably limit anorectal area to 50.4, maybe even 45 given zero visualizable disease). Med onc thinking about just giving platinum now.

Tough case, thanks all for the input.

 

[Palex80]

No right answer.

I'd check p16 staining.

Generally, if positive I treat like an anal cancer -- same fields, RT, chemo (RTOG 0529)
Generally, if negative I treat like a skin cancer -- basically what BobbyHeenan said +cisplatin or cetuximab for +ECE.

You, Sir, are a genius!

Why haven't I never thought of that?

And, yes I am serious! THANK YOU!

 

[evilbooyaa]

Got a 68 yo man with left groin SCC with unknown primary, presented with a 3.5 cm inguinal node he could feel. Underwent quite exhaustive workup to find a primary but nothing found. 4 years ago underwent shave biopsy and freezing of a left thigh SCC that was well differentiated, nothing there now. Underwent left inguinal resection and obturator dissection had 31/36 nodes positive + ECE (4/4 obturators were positive). Most of these were occult bc he only had 2 nodes active on preop PET. GI did another anoscopy didn't see anything, urology/derm sees no e/o penile disease. Did another PET at time of sim, still nothing to suggest a primary.

Curious your guys thoughts on RT field and doses now. Hes being quite resistant to chemo although I see a clear rationale here. Thank you

I think with 31/36 LNs positive and with ECE the guy needs chemo hands down, maybe even more than RT given the extent of occult disease.

Otherwise agree with others. Really like Neuronix's thought process on differentiating, going to be stealing that for myself.