A New Standard of Care? Addition of Hormonotherapy to Radiotherapy Improves Survival in Prostate Cancer

Following radical prostatectomy, radiotherapy is the standard salvage treatment. Researchers assessed the impact of adding short-term hormonotherapy to radiotherapy and found that this significantly improved 10-year metastatic-free survival (MFS). The results of the randomized, open-label, phase III study were presented at the 2019 ASCO Annual Meeting.

A total of 743 patients were randomized 1:1 to receive radiotherapy (66 Gy/46 Gy) alone or in combination with goserelin for six months. Patients were stratified based on radiotherapy modality and risk group. Low-risk disease was defined as a Gleason score less than eight, surgical margins prostate-specific antigen doubling time greater than eight months, and no seminal vesicle involvement. Biological relapse was defined according to the American Society for Radiation Oncology consensus.

At data cutoff (March 2019), the median duration of follow-up was 112 months. The researchers observed a benefit in progression-free survival (PFS; primary outcome) in the radiotherapy plus hormonotherapy cohort (hazard ratio [HR] = 0.54; 95% confidence interval [CI], 0.43-0.68; P<0.0001). This benefit was observed in both low- (HR=0.47; 95% CI, 0.28-0.80) and high-risk (HR=0.56; 95% CI, 0.44-0.73) cohorts.

MFS was significantly improved in the radiotherapy plus hormonotherapy cohort (75%; 95% CI, 70-80) compared with the radiotherapy alone group (69%; 95% CI, 63-74) at 10 years (HR=0.73; 95% CI, 0.54-0.98; P=0.034).

In a 2016 study published in The Lancet Oncology, the researchers conducted a similar study in which patients received standard salvage radiotherapy or radiotherapy plus short-term goserelin. After a median follow-up of 5.3 years, the researchers observed a benefit in PFS in the combination cohort (80% vs. 62%; P<0.0001), regardless of patient risk status.

“Considered in the context of previously published results, [this recent study confirms] that this strategy can be considered as the new standard for salvage treatment after radical prostatectomy,” the researchers concluded.

Reference

Carrie C, Magné N, Burban-Provost P, et al. Interest of short hormonotherapy (HT) associated with radiotherapy (RT) as salvage treatment for metastatic free survival (MFS) after radical prostatectomy (RP): Update at 9 years of the GETUG-AFU 16 phase III randomized trial (NCT00423475). Abstract #5001. Presented at the 2019 ASCO Annual Meeting, Chicago, IL, May 31, 2019.