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Sandy Srinivas, MD
Sandy Srinivas, MD
Posted: Friday, October 20, 2023
According to the findings of reportedly the largest study of testosterone kinetics in patients treated with salvage radiation and androgen-deprivation therapy (ADT), a faster normalization of testosterone levels after treatment was found not to worsen patients’ outcomes. In fact, Alan Dal Pra, MD, of the University of Miami’s Sylvester Cancer Center, and colleagues noted an incremental and meaningful benefit in freedom from disease progression related to adding short-term ADT and pelvic lymph node radiotherapy to prostate bed radiotherapy that was independent of testosterone recovery. The investigators believe these results may have clinical implications for using androgen-suppression drugs that are linked to quicker testosterone recovery and for providing testosterone replacement to patients who experience significant treatment-related adverse effects related to low testosterone levels.
At the 2023 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 261), the team presented their secondary analysis of the phase III NRG/RTOG 0534 SPPORT trial. This study contained three treatment arms: prostate bed radiotherapy (arm 1) with prostate bed radiotherapy plus short-term ADT (arm 2) and with prostate bed radiotherapy plus pelvic lymph node radiotherapy in addition to short-term ADT (arm 3). They focused on 1,699 patients who had testosterone at baseline and at least one follow-up assessment. Dr. Dal Pra and co-investigators measured longitudinal serum testosterone levels and the impact of testosterone recovery on clinical outcomes; ADT was given for 4 to 6 months in arms 2 and 3, starting 2 months prior to radiotherapy.
They defined testosterone recovery in three ways: as return to noncastrate level (> 50 ng/dL), to normal level (> 300 ng/dL), and to baseline level. At baseline, median testosterone levels in arms 1, 2, and 3 were 320 ng/dL, 319 ng/dL, and 330 ng/dL, respectively.
At 6 months, median testosterone levels in arms 1, 2, and 3 were 290 ng/dL, 190 ng/dL, and 191 ng/dL, respectively. At 2 years, in arms 2 and 3, the rates of testosterone recovery to noncastrate, normal, and baseline levels were 95%, 55%, and 23%, respectively. At 5 years, in arms 2 and 3, those percentages were 98%, 73%, and 42%.
Disclosure: Dr. Dal Pra reported no conflicts of interest.
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