Androgen deprivation therapy duration is significantly associated with Testosterone recovery in Japanese patients with prostate cancer.

OBJECTIVE: Due to the fear generated by COVID-19 in Spring 2020, many patients postponed their scheduled outpatient visits. To differentiate those patients with prostate cancer (PCa) whose androgen deprivation therapy (ADT) injection treatment can be postponed, we investigated the characteristics of testosterone (T) recovery in Japanese patients after they received combined ADT and radiation therapy (RT). METHODS: We included 81 patients with PCa treated with ADT and RT at Keio University Hospital from January 2013 to December 2018. T-recovery was defined as the time interval between the last ADT injection and 3-6 months after T-normalization. The Kaplan-Meier method was used to estimate time to T-recovery. Cox proportional hazards models identified T-recovery predictors. RESULTS: The 50% cumulative incidence of T-recovery was 7.0 months for the 6-short-term group (defined as patients having ≤6 months of ADT therapy) versus 13.0 months for the 6-long-term group (>6 months of therapy) (p < 0.001). The incidence was 7.0 months for the 12 short-term-ADT (ST) group versus 18.0 months for the 12 long-term-ADT (LT) group (p < 0.001). Multivariate analysis revealed that a shorter duration of ADT was associated with a shorter time to T-recovery (hazard ratio, 0.253; 95% CI, 0.138-0.465; p < 0.001). No other factors were significant predictors of T-recovery. CONCLUSION: Androgen deprivation therapy duration is significantly associated with T-recovery in Japanese patients with PCa. If a patient undergoes ADT for more than 6 or 12 months, it is possible to postpone their outpatient visits for 13 and 18 months, respectively.