Sayyid RK, et al. – The physicians conducted this work to determine whether continuous androgen deprivation therapy users achieving testosterone levels <0.7 nmol/L illustrate subsequent testosterone level elevations on follow–up and whether such events predict worse oncologic outcomes. Taking into account a large series of patients and an important follow–up period, continuous androgen deprivation therapy users having initial testosterone levels <0.7 nmol/L frequently exhibit subsequent elevations in serum testosterone levels. Moreover, such occurences should not trigger an immediate response from physicians as these events are prognostically insignificant with regards to oncologic outcomes, and patients eventually re–establish levels <0.7 nmol/L.

Methods

• Researchers designed a random, retrospective study including a sample of 514 prostate cancer patients treated with continuous androgen deprivation therapy and having serum testosterone levels <0.7 nmol/L, at the University Health Network between 2007–2016.
• In this research, patients were followed from date of first testosterone level <0.7 nmol/L till progression to castrate resistance, death, or end of study period.
• Study outcomes were occurrence of testosterone level elevations >0.7, >1.1, and >1.7 nmol/L and progression to castrate–resistant state.
• They used survival curves to determine rates of occurrence of testosterone level elevations.
• They applied multivariate Cox regression analysis to evaluate whether occurrence of elevations predicts progression to castrate–resistance.

Results

• 74 years was the median age.
• Median follow–up was 20.3 months was the median.
• The data showed that 82%, 45%, and 18% of patients had subsequent testosterone levels >0.7, >1.1, and >1.7 nmol/L within five years of follow–up, respectively, and 96–100% of such patients subsequently re–established levels <0.7 nmol/L within five years.
• It was showed that none of the patient baseline characteristics were associated with occurrence of elevations.
• In addition, occurrence of elevations was not a significant predictor of progression to castrate–resistant state.