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The following is a summary of “Testosterone Recovery Following Androgen Suppression and Prostate Radiotherapy (TRANSPORT): A Pooled Analysis of Five Randomized Trials from the Meta-Analysis of Randomized Trials in Cancer of the Prostate (MARCAP) Consortium,” published in the September 2024 issue of Urology by Ong et al.

The time to testosterone recovery (TR) following androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists exhibits significant variability across patients. This study aims to investigate the kinetics of TR and assess the oncological impact of the effective castration period in patients undergoing definitive radiotherapy with ADT for prostate cancer.

Researchers analyzed individual patient data from several randomized controlled trials involving radiotherapy and ADT, incorporating serial testosterone measurements from the MARCAP Consortium. Times to non-castrate TR (>1.7 nmol/L) and non-hypogonadal TR (>8.0 nmol/L) were estimated for different prescribed ADT durations, and corresponding nomograms were developed. Furthermore, the study group evaluated the association between the effective castration period and metastasis-free survival (MFS) for each ADT duration using multivariable Cox regression, supplemented by cubic spline analyses to explore potential nonlinear relationships.

The analysis included 1,444 men from five clinical trials, with ADT durations ranging from 4 to 36 months (115 patients received 4 months, 880 received 6 months, 353 received 18 months, 36 received 28 months, and 60 received 36 months). The time to non-castrate and non-hypogonadal TR varied significantly with ADT duration. Higher baseline testosterone levels and younger age were significantly associated with faster TR (p < 0.001 for both factors). The relationship between the effective castration period and MFS was not linear. The cubic spline analysis suggested that the optimal effective castration period for maximizing MFS was 10.6 months for patients who received 6 months of ADT and 18 months for those who received 18 months of ADT.

In conclusion, TR kinetics are influenced by ADT duration, baseline testosterone levels, and patient age. The oncological benefit of a longer effective castration period may be more pronounced for patients receiving shorter ADT durations. This insight into TR dynamics could assist in tailoring ADT regimens to optimize treatment outcomes for patients with prostate cancer.

Source: sciencedirect.com/science/article/abs/pii/S0302283824026010