I believe that we both may be correct in our understanding. When an in-country viet vet has PCa, he is considered 100% disabled during treatment. Grunt was asking about the re-evaluation process. My response assumed that the PCa was "cured/removed" during the treatment process and the re-evaluation just deals with the remaining impacts and side effects of the treatment, which are typically urinary, although there is also some compensation for ED as "loss of a creative organ". (That terminology always cracks me up)
However, if the vet still has PCa at the time of the re-evaluation and is still undergoing treatment, it is my understanding that the disability will remain at 100%.
I'm not sure how they address the PSA bounce or decling values related to radiation, especially Proton Beam, but I assume that those SE will emphasize urinary frequency, although I have heard that some vets that maintain significant PSA levels following radiation may stay at 100% for a longer time. But, that's just a guess on my part.
Regardless, it's certainly not worth it to get PCa to obtain the benefits, but they are substantial. My payments at 100% were about $2,700/month, tax free. The lesser benefits are significantly reduced, but still a big help.