Hi PM Lynch. I’m sorry to hear you are battling prostate cancer. Taking cannabis oil via suppositories is an effective option which decreases the psychoactivity of THC. I wrote an article on the bioavailabilty of cannabis and the different methods of consumption which includes the rectal route. I’ve pasted the section here: Rectal — Anecdotal evidence shows positive results using rectal suppositories. In addition, the rectal approach, when placed correctly (which means avoiding the superior rectal vein), prevents first pass metabolism. Unfortunately, there are very few scientific studies on the bioavailability of rectal administration. One conducted on monkeys showed a bioavailability of 13.5%. Another study conducted with two patients deduced that the bioavailability was approximately twice that of oral ingestion but did not provide bioavailability percentages. In addition, the studies that were conducted showed that “bioavailability strongly differed depending on suppository formulations”, with THC-hemisuccinate having the best results. However, the average person does not have access to hemisuccinates. Lastly, a clean rectum is required before applying the suppository.

To answer your question, many people have used this option with success. Included is a link to a Leafly article which discusses this in more detail. I wish you the best.