The US news is reporting that during the treatment for benign prostate enlargement an 'area of concern' was discovered. Biopsy revealed a malignancy 'in the early stages'.
IANAD (I am not a Doctor) but I'm assuming that they found something 'in the general vicinity' of the prostate during the procedure (ie the bladder) or on the prostate itself, although I believe they're saying 'not the prostate'. And the fact that he is stepping back from duties during treatment indicates to me (based on my DH's treatment of a 'very treatable cancer' that he's undergoing radiation & chemo, probably a course of 6 weeks or so. Again pure speculation on my part.
Wishing him the very best.