PracticeUpdate: Oncology - Winter 2018

EDITOR’S PICKS 14

Three-Month Post-Treatment PSA Level as a Biomarker of Treatment Response in Patients With Intermediate- or High-Risk Prostate Cancer TreatedWith ADT and RT Cancer

Take-home message • This study investigated the association between 3-month post-radiotherapy (RT) PSA level and biochemical progression-free survival (bPFS), prostate cancer–spe- cific survival (PCSS), and overall survival (OS) in 5783 patients with intermediate- or high-risk localized prostate cancer treated with RT and androgen deprivation therapy. Patients were divided into groups based on 3-month post-RT PSA values: <0.10 ng/mL, 0.10 to 0.49 ng/mL, and ≥0.50 ng/mL. There were 2651 patients with intermediate-risk and 3132 with high-risk disease; approximately 11% had a 3-month PSA level of ≥0.50 ng/mL. A higher 3-month PSA level was found to be strongly associated with each outcome; compared with patients in the group with a 3-month PSA value <0.10 ng/mL, the authors noted greater hazards for the patients with a 3-month PSA value ≥0.50 ng/mL (HR for bPFS: 5.23; PCSS: 3.97; and OS: 1.50 [P < .001 for all]) and the patients with a 3-month PSA value of 0.10 to 0.49 ng/mL (HR for bPFS: 2.41 [P < .001]; PCSS: 2.29 [P < .001]; and OS: 1.21 [P < .003]). When analyzed separately, the 3-month PSA level was found to be predictive of OS in the high-risk group (P < .001) but not the intermediate-risk group (P = .21). • The study authors concluded that the 3-month post-RT PSA level appears to be a strong prognostic biomarker for bPFS, PCSS, and OS in patients with intermediate- risk and high-risk prostate cancer, particularly in those with high-risk disease. Jeffrey Wiisanen MD COMMENT By Brian E Lewis MD, MPH T his was a study utilizing a large national database, the VA Informat- ics and Computing Infrastructure

Abstract BACKGROUND Prostate-specific antigen (PSA) measurement after definitive radiotherapy (RT) and androgen deprivation therapy for localized prostate cancer has been proposed as an early prognostic biomarker. In the current study, the authors investigated the association between 3-month post-RT PSA level and biochemical progression-free survival (bPFS), prostate can- cer-specific survival (PCSS), and overall survival (OS).

This was a large study with nearly 5800 patients, which shows that the PSA value at 3months post radiation therapy will help predict who will relapse. This can give us an earlier signal about who may need additional therapy in the future and who we can reassure. I don’t think that this will change the way we currently practice, but we could potentially use the 3-month PSA to determine who may benefit from early salvage therapy in the setting of a clinical trial.

(VINCI), which contains health record data on veterans within the Veterans Affairs healthcare system. The authors evaluated veterans with prostate cancer who were treated with androgen-depri- vation therapy and concurrent radiation therapy from 2000 to 2015. The 3-month post-treatment PSA was divided into three categories: <0.1, 0.1–0.49, and >0.5. For men with high-risk prostate cancer (T3a or T3b, Gleason 8–10, or pretreat- ment PSA >20), the PSA at 3 months was predictive of biochemical progres- sion-free survival, overall survival, and prostate cancer-specific survival. For men with intermediate-risk prostate can- cer (T2b or T2c, Gleason score of 7, or a pretreatment PSA between 10 and 20), the PSA at 3 months was predictive of biochemical progression-free survival and prostate cancer-specific survival.

" I don’t think that this will change the way we

Dr. Lewis is an Assistant Professor of Clinical Medicine in the Department of Hematology and Medical Oncology at Tulane University School of Medicine in New Orleans. He is also Associate Program Director of the

currently practice, but we could potentially use the 3-month PSA to determine who may benefit from early salvage therapy in the setting of a clinical trial. "

Hematology and Medical Oncology Fellowship Program at Tulane and Chair of the Fellowship Advancement Committee.

PRACTICEUPDATE ONCOLOGY