Investigators who studied men who underwent primary external beam radiation therapy (EBRT) for prostate cancer found “fairly high” rates of biochemical recurrence of disease, investigators reported at the American Urological Association’s 2023 Annual Meeting in Chicago, Illinois.
In addition, rates of salvage treatment were “relatively low in comparison, indicating that not all patients who recur need, are offered, or want treatment,” Domenique Escobar, MD, of the University of California, San Francisco, and colleagues concluded in a study abstract.
In a study that included 1193 patients with clinically localized cancer who had primary EBRT, the investigators found overall biochemical recurrence rates of 17.4% at 5 years and 39.4% at 10 years. They defined biochemical recurrence as PSA nadir plus 2 ng/dL.
The risk varied by National Comprehensive Cancer Network (NCCN) clinical risk category. Patients with high-risk prostate cancer had the highest biochemical recurrence rates (61.5%), followed by those with intermediate- and low-risk disease (36.4% and 28.5%, respectively). Compared with patients who had low-risk disease, those with high-risk disease had a significant 4.8-fold increased risk for biochemical recurrence.
Salvage treatment rates were 16% and 19% at 5 and 10 years, respectively, Dr Escobar’s team reported. Overall rates of bone metastases were 2.6% and 4.0% at 5 and 10 years, respectively. The rates of prostate-cancer specific mortality were 3% and 7%, respectively.
The investigators identified study patients using the CaPSURE database, a national registry of men diagnosed with prostate cancer.
Dr Escobar’s team noted that the strengths of the study include the large cohort size and length of follow-up. They concluded that since their cohort largely represents treatment in community settings, the findings may be broadly applicable.
Escobar D, Wang L, Banton J, et al. Long-term rates of biochemical recurrence after primary external beam radiation therapy for prostate cancer. Presented at: AUA 2023, April 28-May 1, Chicago, Illinois. PD15-05.