Prostate cancer hormone therapy benefit not predicted by pathology score
A five-trial analysis found high-risk pathology after surgery signals worse outcomes but did not identify who gained more from hormone therapy.
By Tom Brennan · Health & Medicine Correspondent
3 min read
A new analysis of the prostate cancer hormone therapy benefit after surgery found that a count of four high-risk pathology findings did not identify which patients gained more from adding hormone treatment to radiation. The result matters because those findings still marked a greater risk of death or cancer spread, yet did not distinguish treatment benefit in this analysis.
The study, led by Dr. Amar Kishan and published online July 28 in European Urology, pooled individual data from five randomized phase 3 trials. It included 4,781 patients who received radiotherapy after prostate surgery and followed them for a median of 9.1 years, according to the journal article.
Can pathology findings predict hormone therapy benefit after prostate surgery?
Not in this study. Researchers created a score from zero to four based on whether surgical pathology showed Grade Group 4-5 disease, cancer in the seminal vesicles, positive surgical margins, or extracapsular extension, meaning cancer had extended outside the prostate.
A higher score was prognostic: it was associated with poorer overall survival and metastasis-free survival. A prognostic factor signals the likely course of a disease; a predictive factor identifies who may benefit more from a particular treatment. The score did not show that predictive role for hormone therapy added to postoperative radiation, the researchers reported.
- For overall survival, the interaction hazard ratio was 0.93, with a 95% confidence interval of 0.79 to 1.10 and a p value of 0.4.
- For metastasis-free survival, the interaction hazard ratio was 0.88, with a 95% confidence interval of 0.77 to 1.01 and a p value of 0.08.
In plain language, those analyses did not find statistically significant evidence that accumulating more of the four pathology findings changed the benefit from hormone therapy. The result was similar when researchers grouped patients by score, looked at high-risk subsets or used a narrower score based only on Grade Group 4-5 disease and seminal vesicle invasion, according to the paper.
The authors said the finding is particularly relevant to patients whose prostate-specific antigen, or PSA, was no higher than 0.5 ng/mL before radiation. It does not establish that hormone therapy has no role after surgery or address initial radiation treatment in people whose prostates remain intact.
The paper also described results from an earlier POSEIDON analysis. In that prior work, patients with PSA at or below 0.5 ng/mL had a projected absolute 10-year overall-survival benefit of less than 1% from hormone therapy, while those above 0.5 ng/mL had projected 10-year benefits greater than 7% for metastasis-free survival and 4.5% for overall survival.
UCLA Health said hormone therapy may be added to radiation for some patients after surgery and can have potential side effects including fatigue, hot flashes, sexual dysfunction, bone loss and metabolic changes. The researchers said molecular biomarkers may be needed to better predict who benefits from additional treatment. Treatment choices require discussion between patients and their clinicians.
This story draws on original reporting from Medical Xpress.