Focal therapy for intermediate-risk prostate cancer: a novel treatment approach
For the last two years, I have worked as the consulting statistician on a multicenter study of a novel treatment for intermediate-risk prostate cancer with my coworkers and researchers from Harvard, Weill Cornell, Mayo Clinic, Stanford, City of Hope, and UCLA. In 2021, we published an abstract based on six-month biopsy and one-year quality of life (QOL) follow-up data. Since then, the treatment has received FDA approval and our complete two-year biopsy and QOL results have been published in The Lancet Oncology. In this post I want to give a brief background and overview of the study.
Prostate cancer is the most commonly diagnosed cancer among U.S. men, but it presents with a wide range of severity and risk of progression. Physicians use the Gleason Grade Group (GG) system to categorize patients' risk on a scale of low-risk GG1 to high-risk GG5 disease. This categorization is usually used to determine the treatment path for patients diagnosed with prostate cancer. Those with GG1 cancer are generally recommended for active surveillance, where their tumors are closely monitored for signs of progression, while patients with GG4 or GG5 cancers typically receive combinations of chemotherapy, radiation, and surgery targeting the entire prostate gland. Patients with intermediate-risk GG2 or GG3 disease are often considered ineligible for active surveillance and are also recommended for these more aggressive, systematic treatments. Although they are highly effective, these treatments also have high risks of side effects that affect quality of life (QOL), including erectile dysfunction and urinary incontinence. The purpose of this study was to evaluate the oncologic efficacy and QOL impact of an alternative to whole gland therapy for patients with intermediate risk prostate cancer: Magnetic Resonance guided Focused Ultrasound (MRgFUS) focal therapy.
This focal therapy approach uses image-guided ultrasound waves to ablate only the largest lesion on the prostate, preserving normal tissues and surrounding structures. The study recruited 101 men with intermediate-risk GG2 or GG3 prostate cancer to trial the new treatment and to be monitored by biopsy, follow-up appointments, and QOL surveys for two years.
My role as biostatistician was to analyze the biopsy and QOL survey data and write the statistical methods and results. We used descriptive statistics to report the biopsy results and generalized estimating equation (GEE) models to assess changes in QOL survey scores over time.
Our final results published in the The Lancet Oncology show that the large majority of patients who started with GG2 and GG3 cancer no longer had GG2+ disease in the treated area of the prostate. Additionally, survey scores for erectile function and urinary continence compared favorably with alternative treatments like radical prostatectomy.
