[Prognostic value of testosterone during androgene deprivation therapy]

The concept of intermittent androgen deprivation therapy (IADT) for prostate cancer (PCa) was introduced in order to improve treatment tolerance with the same carcinological efficiency as continuous androgen deprivation therapy (CADT). Furthermore, studies have shown that PCa prognosis during CADT was correlated to the extent of testosterone collapse. The aim of this study was to assess the link between testosterone levels at the end of the first off-treatment phase and time to occurrence of castrate-resistant prostate cancer.

We retrospectively analyzed the files of 69 patients having undergone IADT. Intermittence was offered to the patients showing PSA<4ng/mL after at least six months of androgen deprivation therapy (ADT) using a LHRH analog. CRPC was defined according to the AFU oncological guidelines. Patients were sorted into three groups according to their testosterone levels at the end of the first off-treatment phase T<0.5ng/mL, 0.53.4ng/mL. CRPC free-survival, metastasis-free survival and overall survival as well as adverse events frequency were compared between the groups. The impact of initial ADT duration on CRPC occurrence, mean off-treatment phase duration and IADT duration was also studied.

Testosterone levels at the end of the first and second off-treatment phases were not linked to time to CRPC occurence (p=0.5), mestastasis occurence (p=0.4) or death (p=0.3). It was associated neither with adverse effects frequency (p=0.2) nor with cancer-related complications (p=0.6). Initial ADT duration was not linked to CRPC occurrence (p=0.6), mean off-treatment phase duration (p=0.5) or mean IADT duration (p=0.6).

This study did not show any link between testosterone levels at the end of the first off-treatment phase (before reintroducing ADT) and overall survival, metastasis-free survival and CRPC-free survival. Likewise, it was not associated with the frequency of adverse events or cancer-related complications. Initial ADT duration was not linked to CRPC occurrence or IADT chronological parameters.