Short-Term Androgen Suppression Improves PFS After Radical Prostatectomy for Prostate Cancer

By Will Boggs MD

November 05, 2019

NEW YORK (Reuters Health) - Short-term androgen deprivation therapy added to radiotherapy as salvage therapy after radical prostatectomy for prostate cancer improves 10-year progression-free survival, according to a follow-up of the GETUG-AFU 16 phase 3 trial.

However, there was no effect on overall or cancer-specific survival, researchers report in The Lancet Oncology, online October 16

Salvage radiotherapy is the standard treatment for patients with biochemical recurrence after a radical prostatectomy for prostate cancer. Initial results from GETUG-AFU 16 showed significant improvements of progression-free survival (PFS) at five years in men treated with combined short-term androgen suppression with goserelin for six months plus radiotherapy over those treated with radiotherapy alone.

In the current study, Dr. Christian Carrie of the University of Lyon, in France, and colleagues evaluated PFS and metastasis-free survival four years after the original study.

After a median follow-up of 112 months, 33% (120/369) of men who received radiotherapy plus goserelin had progression or died, compared with 50% (187/373) of men who had only radiotherapy.

The 120-month PFS was 49% in the radiotherapy group versus 64% in the combination group, representing a significant 46% risk reduction (P<0.0001).

The 120-month metastasis-free survival was also significantly higher among men in the radiotherapy-plus-goserelin group (75%) than among men in the radiotherapy alone group (69%).

Overall survival at 120 months did not differ significantly between the groups, at 86% in the combination group versus 85% in the radiotherapy-alone group. Mortality due to cancer also was not significantly different, at 5% versus 3%, respectively.

At 120 months, the number of men needed to treat to prevent one metastasis or death when adding androgen suppression to radiotherapy was 14.

"The results of the GETUG-AFU 16 trial confirmed the efficacy of androgen deprivation therapy plus radiotherapy as salvage treatment in patients with rising PSA concentrations after radical prostatectomy, as evidenced in the RTOG trial for patients with more aggressive relapse," the authors conclude.

Dr. Anthony V. D'Amico of Brigham and Women's Hospital and Dana Farber Cancer Institute, in Boston, who wrote a linked editorial, told Reuters Health by email, "GETUG AFU-16 enrolled older men with more favorable prognostic factors than those enrolled on RTOG 9601 and followed them for a shorter time. Therefore, the lack of a survival benefit does not mean one may not be seen with further follow-up."

"It also remains possible that in this more-favorable cohort perhaps no or less than 6 months of an LHRH agonist is all that is needed to improve survival," he said. "The results of RADICALS will be able to better answer this question in time."

"For now, given that the addition of 6 months of the LHRH agonist to radiotherapy resulted in a non-significant reduction in death from prostate cancer . . . and a significant decrease in progression by 50%, continued use of 6 months of an LHRH agonist is indicated until more specific information is available from the RADICALS trial on whether no, 6 months, or 2 years of an LHRH agonist is best," Dr. D'Amico said.

Dr. Carrie did not respond to a request for comments.

AstraZeneca funded the GETUG-AFU 16 study and had ties to one of the authors.

SOURCE: https://bit.ly/2PF3idw and https://bit.ly/34jzkjf

Lancet Oncol 2019.

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