How do you manage favorable intermediate risk prostate cancer patients that have a PIRADS 5 lesion that was most-likely missed in the template biopsy?

Yes, I'd suggest a repeat biopsy before treatment. In the case of radiation +/- ADT, a repeat biopsy may impact the dosimetry of radiation, whether or not ADT is used, and how long ADT is used as part of treatment.

I definitely recommend a targeted biopsy of an anterior PI-RADS 5 lesion. The only exception that comes to mind is systematic biopsy already showed grade group 4-5 cancer in the posterior gland (i.e., a new cancer won’t change management).

I agree with Dr. @Dr. First Last's answer. I'd also wait before sending a Decipher in this case, as the Decipher should, ideally, be performed on the tissue with the highest Grade Group score.

MR guided repeat biopsy