Identification of Factors Contributing to Testosterone Recovery After Hormone Therapy Combined With External Radiation Therapy

When hormone therapy (HT) is combined with radiotherapy, understanding the recovery of testosterone levels after the end of HT becomes crucial for considering subsequent therapy. The aim of this study was to determine the factors influencing the time to recovery of testosterone levels after discontinuation of HT and the likelihood of recovery.

The study included a total of 108 patients with prostate cancer who were treated with GnRH agonist in combination with radiotherapy and followed up for at least 12 months after discontinuation of the GnRH agonist. The presence of recovery of testosterone levels and the time to recovery were investigated. Univariate and multivariate analyses were performed on several factors contributing to testosterone recovery, including age at initiation of HT, and the duration of HT.

Testosterone levels recovered in 61 cases (56.5%). The median time to recovery was 14.8 months. There was a significant difference in the recovery of testosterone levels between patients aged ≥71 years and those aged <71 years at the start of HT (p=0.002), and between those who had been on HT for ≥34 months and those for <34 months (p=0.031). In both univariate and multivariate analyses, age at initiation of HT and duration of HT contributed to the recovery of testosterone levels.

The rate of recovery of testosterone levels after long-term (median 34.3 months) HT was lower in patients who were older than 71 years at the start of HT.