Dr. Chi on the Rationale for the PC-BETS Study With ctDNA in Prostate Cancer

Kim Chi, MD, senior research scientist, Vancouver Prostate Centre, chief medical officer and vice president, BC Cancer, medical oncologist, BC Cancer, professor, Department of Medicine, University of British Columbia, discusses clinical challenges in prostate cancer.

One of the greatest challenges in prostate cancer has always been the ability to obtain tissue, whether its archival or tissue from fresh biopsies, says Chi. Going along with this, in several PARP inhibitor trials, investigators were unable to obtain either positive or negative results from assays due to inadequate tissue samples, explains Chi.

It’s now widely understood that biopsies are often challenging for patients with prostate cancer, especially those with bone metastases, adds Chi. With these patients, it can be particularly difficult to obtain efficient samples.

In the prostate cancer biomarker enrichment and treatment selection (PC-BETS) study, investigators evaluated antitumor activity of novel targeted therapies in patients with metastatic castration-resistant prostate cancer. In this umbrella trial, circulating tumor DNA (ctDNA) was used from the start, explains Chi. Graciously, a majority of the patients, even those with advanced disease following disease progression on 1 or 2 lines of therapy, had an abundance of ctDNA available for analysis, Chi concludes.