Early Detection of Neuroendocrine Prostate Cancer as Lineage Plasticity in Recurrent Prostate Cancer After Radiation and Androgen Deprivation Therapy: A Case Report

Background: Neuroendocrine prostate cancer is one of the most aggressive prostate cancers, with severely poor prognosis. However, its detection is difficult because no useful marker has been found so far. In addition, serum prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA), and PSMA positron emission tomography/computed tomography don’t help in neuroendocrine prostate cancer. However, its early detection is necessary because its prognosis is poor.Case presentation: We described three cases of early neuroendocrine prostate cancer detection after initial external beam radiotherapy followed by salvage androgen deprivation therapy (ADT). We used Magnetic Resonance Imaging for three ADT-resistant patients, and it detected neuroendocrine prostate cancer in all three, although the PSA level was <2 ng/mL.Conclusions: Magnetic resonance imaging might be a better modality for neuroendocrine prostate cancer detection despite low serum prostate-specific-antigen levels.. Our findings in these three cases will help establish better criteria or better follow-up for patients administered salvage androgen deprivation therapy for biochemical recurrence of prostate cancer after external beam radiotherapy.

Early versus delayed initiation of salvage androgen deprivation therapy and the risk of prostate cancer-specific mortality.

189 Background: We sought to ascertain whether there is an association between prostate cancer (PC)-specific mortality (PCSM) and salvage androgen deprivation therapy (ADT) timing amongst men with short versus long prostate-specific antigen doubling times (PSA-DT)s. Methods: The study cohort was selected from 206 men with localized unfavorable-risk PC who were randomized to radiation therapy (RT) or RT plus 6 months of ADT between 1995 and 2001. Fifty-four men who received salvage ADT for PSA failure after a median follow up of 18.72 years following randomization defined the study cohort. Fine-Gray competing risks regression analyzed whether the timing of salvage ADT was associated with an increased risk of PCSM after adjusting for age, comorbidity, known PC prognostic factors, and previously identified interactions. Results: After a median follow-up of 5.68 years (IQR 3.05 - 9.56) following salvage ADT 49 of the 54 men (91%) died, 27 from PC (54% of deaths). Increasing PSA-DT as a continuous covariate was associated with a decreasing risk of PCSM (adjusted hazard ratio [AHR] 0.33, 95% CI 0.13, 0.82; P=0.02). Amongst men with a long PSA-DT (≥6 months), initiating salvage ADT later (PSA>12ng/mL, upper quartile) versus earlier was associated with an increased risk of PCSM (AHR 8.84, 95% CI 1.99-39.27; P=0.004); whereas for men with a short (<6 months) PSA-DT (AHR 1.16, 95% CI 0.38-3.54; P=0.79) this was not true. Conclusions: Early initiation of salvage ADT for post-RT PSA recurrence in men with a PSA-DT of 6 months or more may reduce the risk of PCSM, arguing against the unproven assumption that patients with a short PSA-DT are those most likely to benefit from early initiation of salvage ADT. Clinical trial information: NCT00116220.