What is the optimal treatment for a locally advanced rectal cancer on the anterior wall abutting the prostate in a medically inoperable patient with a remote history of LDR brachytherapy for low risk prostate cancer?  

I would start with chemotherapy if that is an option and tailor RT dose to some extent based on response. If there is great response even local excision can be evaluated? Rectal and urethral complications are high and I have seen patients developing these complications even with 45 to 50.4 Gy preop ...

According to my colleagues who specialized in GU, the LDR monotherapy usually has a prescription dose of 125 Gy (Pd) and 145 Gy (iodine) with a rectal constraint of V100% < 1%. So, there is a relatively high point dose just posterior to the prostate but the overall dose to the entire rectum shoul...

I would propose proton therapy as an option for re-irradiation. This would reduce the dose to the urethra to essentially 0. There is, of course, always a problem of the rectum and whatever max point dose was received from the LDR.   However, depending on the patient and goals of care, aggress...

Thanks, @Sushil Beriwal. I agree that we should try to avoid re-irradiation, especially high dose re-irradiation. Starting with chemotherapy first is also what we do. If local excision is possible, we would do that too. The RT field for re-irradiation is usually small (only cover gross tumor) to de...

I like suggestions from Dr. @Lin and @Quinn. We often provide pelvic radiation 45-50 Gy in conjunction with seed implant. So standard fractionation to that dose is safe. With distant history of seed implant, a dose of 50.4 to 54 Gy is reasonable at standard fractionation. I suggest: Neo-adjuvant ch...

This is a complex patient, why is the patient medically inoperable? Is it co-morbidities? If so, I then am not sure if he would be eligible to get high-dose systemic therapy. Although, that would be my first choice, if he is eligible for doublet/triplet chemotherapy. In regards to radiation, as...