Treatment of synchronously-diagnosed rectal and prostate CA

[medgator]

I've come across my 2nd case of this in practice (never really saw it in residency) where a guy getting worked up for rectal CA (cT3N1 in both cases) with pelvic/rectal MRI is found to have a localized prostate CA as well. In both of my cases, they ended up having G8-9/high-risk disease.

I thought it over and got input from others and decided on 50.4/28 fractions to both prostate/SVs and rectal CA along with the pelvic lymphatics followed by an HDR boost given 1) high-risk disease and 2) less rectum treated prior to LAR/TME which the patient underwent after treatment of the prostate CA. Pt was started on Lupron a couple of weeks before XRT with plans for 2-3 years of ADT. We couldn't really wait longer than that as the rectal CA was fairly obstructive/bleeding. One pt got Xeloda during Lupron and XRT, the other 5-FU.

One of my older partners suggested Lupron for awhile, pre-op XRT for rectal CA alone, TME surgery, and then brachy after surgery for prostate CA, which made no sense to me personally as you've burned your bridges to some degree with the first plan (and trying to TRUS an anastomosis potentially).

Would anyone do anything differently?

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[Mandelin Rain]

I've seen this 3 times in the past year. Doing a lot of US and MRI staging of rectal cancer, and the MRs pick up high PIRADS lesions that then get worked up.

I've been dose painting the pelvis and rectum to 50.4 Gy and taking the prostate to a moderately hypofractionated treatment of 28 fractions as per 0415. I'll admit though, I've been gun shy about taking them all the way up in 2.5 Gy fractions due to the concurrent 5 FU and need for rectal surgery after. I've always assumed about a 10% sensitization from 5FU (based on very little science, none in prostate cancer), so I've been doing 28 x 2.25 Gy to the prostate, assuming this 10% "kick" to bring it in line with the 0415 dose. Always with concurrent ADT as well. I've had good tolerance in these guys and no operative complications that I know of (yet [knocks on wood]), so I may bump it up to 2.5 Gy fractions moving forward.

I had considered doing an I125 implant after rectal surgery (no HDR experience), but the obvious problem of potentially losing the rectum at surgery and thus any chance of using TRUS, and then having an anastomosis to deal with etc.... Rather just dose paint EBRT preop and hope they cut out the treated rectum. Not sure about doing HDR pre-op as you suggested. Probably reasonable.

 

[evilbooyaa]

Generally the rectal cancer is going to be what's life limiting in this situation. I get that he has G8-9 high risk disease, but still. I think what you've been doing is fine and certainly reasonable. I think doing HDR boost pre-op and then having the rectum removed (can't have rectal toxicity if there's no rectum) is the way to go rather than after surgery.

In regards to post-op implant, I'd worry a lot more about the anastomosis. Also you'd be trying to TRUS through a non-rectum. God forbid he didn't get primary anastomosis and has a colostomy and then you're stuck.

Any thoughts to Pre-op XRT for the rectum only, and then combo surgery (LAR + Prostatectomy)? Not sure if that makes as much oncologic sense since you'll be treating most of the prostatic lymph node basins with the rectal treatment anyways.

 

[medgator]

Any thoughts to Pre-op XRT for the rectum only, and then combo surgery (LAR + Prostatectomy)? Not sure if that makes as much oncologic sense since you'll be treating most of the prostatic lymph node basins with the rectal treatment anyways.

My concern would be adjuvant Tx in the high-risk pt. What do you do about post-op ECE/SVI when you've already given 50.4 Gy to the pelvis pre-op?

 

[evilbooyaa]

My concern would be adjuvant Tx in the high-risk pt. What do you do about post-op ECE/SVI when you've already given 50.4 Gy to the pelvis pre-op?

Fair point. Would be case-by-case dependent (centralized tumor not getting close to ECE/SVI but not too close to Apex to leave + SM), but I agree it certainly could cause issues down the line.

 

[seper]

I'm afraid LAR after prostate brachy is extremely hard to do.

 

[medgator]

I'm afraid LAR after prostate brachy is extremely hard to do.

Ldr or hdr? I don't see a problem post hdr with the correct time frame. I think it would be less rectal dose than 79.2-81 Gy imrt

 

[seper]

I have some experience watching patients having a hysterectomy after cervical HDR ("salvage" for persistent disease or planned completion surgery). Lots of nasty postop complications: fistulas of all kind, bowel obstruction, complete loss of the urinary function.

Ldr or hdr? I don't see a problem post hdr with the correct time frame. I think it would be less rectal dose than 79.2-81 Gy imrt