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Sandy Srinivas, MD
Sandy Srinivas, MD
Posted: Wednesday, November 2, 2022
Findings recently presented at the 2022 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract LBA 05) suggest that combining metastasis-directed therapy with intermittent hormone therapy may improve progression-free survival in patients with oligometastatic prostate cancer. According to Chad Tang, MD, of The University of Texas MD Anderson Cancer Center, Houston, the combination was well tolerated and lengthened the duration men could maintain a break from hormone therapy without disease progression.
“We know that radiation technology has evolved to directly target metastases, to reduce side effects, and to better treat men with prostate cancer,” said Dr. Tang in an institutional press release. “This study provides much-needed data on the benefits of combining these newer radiation techniques with hormone therapy to improve outcomes.”
The phase II EXTEND trial randomly assigned 87 men with five or fewer metastases to continue prior hormone therapy with or without metastasis-directed therapy. The hormone therapy regimen consisted of a luteinizing hormone–releasing hormone agonist or antagonist with or without a second-generation androgen receptor (AR)-targeting agent. Participants underwent a planned break 6 months after enrollment, during which hormone therapy was discontinued until disease progression.
After a median follow-up of 22.1 months, the median progression-free survival was not reached in men who received the combination therapy. In contrast, the progression-free survival in men who received hormone therapy alone was 15.8 months (hazard ratio = 0.25; 95% confidence interval [CI] = 0.12–0.55; P < .001). This improvement occurred independently of second-generation AR-targeting agent treatment. Separately, the median time from eugonad testosterone levels (> 150 ng/dL) to disease progression was lengthened by metastasis-directed therapy (not reached vs. 6.1 months, P = .03), and the 2-year appearance rate of new lesions was also lower in those who received metastasis-directed therapy (33% vs. 41%; P = .04). In an exploratory analysis, the investigators observed increased levels of T-cell activation, proliferation, and clonal expansion markers in the combined therapy arm.
Disclosure: For Dr. Tang’s disclosures, visit plan.core-apps.com.
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