Does incidental seminal vesicle invasion on RT planning MRI for an otherwise cT1-T2 patient influence your recommendation on ADT or pelvic fields?

The finding of seminal vesicle invasion on either a diagnostic MR or planning MR would definitely raise concerns for more advanced and aggressive cancer than a DRE staged cT1-T2 prostate cancer. In most cases, there may be other indications of tumor aggressiveness that would precede an incidental finding on a planning MRI. For example, the initial PSA or Gleason score may place the patient into an intermediate or high NCCN risk category.

I would add 4-6 months of ADT if that were the only advers...

If the MRI is discordant with the rest of an otherwise "low-risk" or "low-intermediate-risk" lesion, I would typically refer the patient to urology for "involved" SV biopsy. More often than not, in my experience, a "(+)" MRI in this setting has been a FALSE "(+)" . . With a (-) SV biopsy result in hand, I would then continue to manage them per std "low- or low-intermediate-risk" schema. If the MRI finding is pathologically verified, then of course, it switches to "high-risk" disease management s...

I agree that seeing unexpected SVI could potentially alter management assuming that you believe the radiographic interpretation and that the finding is reasonably congruent with the clinical case otherwise.

Each practice will have its own test characteristics of MRI. When we first started eMRIs we had case conferences with radiology, pathology, and surgery present to correlate the preop MRI with prostatectomy pathology. This told us that our accuracy for SVI was ~85% and ~50% for ECE. As a resu...

I would believe findings of mpMRI completed in 3T MR scanner, but I am not sure how much information a regular planning MR provides (planning MR protocol varies significantly among institutions). SV invasion in mpMRI definitely raises my concern that this is locally aggressive disease, and I will recommend definitive RT (either high dose IMRT or combination of IMRT and HDR brachy) combined with short-term ADT. Even though sensitivity and specificity of mpMRI is not 100%, this is still much bette...