In a paper published in JAMA Oncology, Tilki et al reported that the current standard monitoring of prostate-specific antigen (PSA) following radical prostatectomy—1.5 to 2 months—is too short to accurately identify recurrence and inform treatment decisions. Rather, PSA levels should be measured for at least 3 months to avoid overtreatment, investigators recommended.
“Checking the PSA level too soon can lead clinicians to mislabel a patient as having recurred and prompt referral to radiation and medical oncologists to initiate salvage radiation and hormonal therapy,” said senior study author Anthony D’Amico, MD, PhD, Chief of Genitourinary Radiation Oncology at Brigham and Women’s Hospital. “It can take longer than 3 months for many patients who have PSA levels > 20 prior to surgery to completely clear the PSA from their bloodstream.”
Anthony D’Amico, MD, PhD
The cohort study included approximately 42,000 patients with prostate cancer. Researchers aimed to evaluate the time necessary to accurately document a persistent PSA level after radical prostatectomy. They investigated whether a significant interaction existed between:
- A presurgical PSA level of > 20 ng/mL vs ≤ 20 ng/mL
- Persistent PSA vs undetectable PSA after radical prostatectomy on prostate cancer–specific and all-cause mortality risk, adjusting for known prognostic factors, age at surgery as well as the year of surgery, and the time-dependent use of postsurgical radiation therapy and androgen-deprivation therapy.
Whether an increasing persistent PSA level was associated with a worse prognosis was also investigated.
Among patients with a persistent PSA, pre-prostatectomy levels of > 20 ng/mL were associated with reduced all-cause and prostate cancer–specific mortality risk compared to patients with levels of ≤ 20 ng/mL. The study authors wrote, “To find a reason for the more favorable prognosis in patients with a higher pre–radical prostatectomy PSA level, we hypothesized that a higher proportion of patients with a pre–radical prostatectomy PSA greater than 20 ng/mL compared with 20 ng/mL or less assessed for a persistent PSA at the conventional 1.5-month to 2.0-month time point post-RP could have reached an undetectable PSA level if further PSA assessment was performed before initiating post-RP therapy for a presumed persistent PSA.”
“The clinical significance of these findings is that they highlight the need to monitor PSA after surgery for longer than the commonly practiced 1.5 to 2 months before concluding that PSA levels are persistent and initiating additional therapy,” said Dr. D’Amico.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
