Treatment for small cell/neuroendocrine prostate is extrapolated from data on small cell lung cancer. It now appears that Carboplatin + Etoposide + Atezolizumab followed by maintenance Atezolizumab is the new first-line treatment for extensive-stage small cell lung cancer based on the phase III study IMpower133 that showed OS and PFS benefit over Carboplatin + Etoposide + Placebo.
https://www.nejm.org/doi/full/10.1056/NEJMoa1809064
I have a patient now to whom I am addressing this ...