Radiotherapy for Prostate Cancer and Risk of Second Primary Cancer

By: Victoria Kuhr, BA
Posted: Thursday, September 29, 2022

After 10 years of treatment with primary radiotherapy, some patients with prostate cancer were observed to be more likely to develop a second primary cancer than those who did not receive radiotherapy, based on a cohort study of more than 140,000 patients with localized prostate cancer and a median follow-up of 9 years. Additionally, Arden M. Morris, MD, MPH, of Stanford University and Palo Alto Veterans Health Care System, California, and colleagues reported that bladder cancer was the most frequently diagnosed second primary cancer. These study findings were published in JAMA Network Open.

“Primary radiotherapy for the treatment of prostate cancer was associated with a small but significantly higher risk of both leukemias and lymphomas compared with other treatment modalities,” said the study authors.

The retrospective study used the Veterans Affairs Corporate Data Warehouse to identify male veterans older than 18 who had localized prostate cancer (tumor stages T1–T3) diagnosed between January 2000 and December 2015. Eligible patients also needed to have no history of cancer. The study compared patients who received primary radiotherapy in the year after diagnosis (radiotherapy cohort) with patients who received a primary surgical procedure, active surveillance, medical management, or observation (nonradiotherapy cohort).

The study included 143,886 patients who had a median follow-up of 9 years. Overall, 4,257 patients (3%) were diagnosed with a second primary cancer more than 1 year after their prostate cancer diagnosis. This percentage comprised 1,955 patients (3.7%) in the radiotherapy cohort and 2,302 patients (2.5%) in the nonradiotherapy cohort. The median time to development of any second primary cancer was 6 years after the prostate cancer diagnosis. Patients in the radiotherapy cohort had a higher risk of second primary cancer compared with those in the nonradiotherapy cohort at years 1 to 5 after diagnosis. Patients in the radiotherapy cohort also had higher adjusted hazard ratios in the subsequent 15 years.

Disclosures: For full disclosures of the study authors, visit jamanetwork.com.

JAMA Network Open

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