@tom, back to your question...8 months ago, I had radical prostatectomy with pathology findings of 4+3=7, 15% involvement, no cancer seen outside the prostate except seminal invasion. Lymph nodes negative. Dr. (and I) said, "No treatment now until we see the PSA post -op." So far @ 6 weeks, 3 & 6 months, it's undetectable, so no further treatment for now.

In my research of this issue, I found the paper I've linked below. It proposes that T3b is too broad a category, and those with ONLY seminal vessel invasion fare better than those with bladder neck. I found it reassuring. I also think, since the seminal vessels were removed, that following the PSA is the right course. Even without that involvement, I still would be at risk for future recurrence, so my attitude is not worsened by the path report.
https://meridian.allenpress.com/aplm/article/146/5/619/476351/The-Clinical-Impact-of-pT3a-Lesions-in-Patients