Top Line: Metastatic, castration resistant prostate cancer (mCRPC) is a biologically diverse disease. So, it’s not unexpected that disease response and progression are heterogeneous processes.
The Study: The goal of this study was to quantify mCRPC response and progression at the level of individual bone metastases within patients. To do that, men with at least 2 bone lesions on bone scintigraphy underwent baseline NaF PET/CT prior to starting enzalutamide. The NaF PETs were then quantitatively analyzed to assess individual lesion-level uptake. Patients had another PET at 13 weeks and a final PET at the time of progression to quantify changes in individual metastatic sites. Qualitatively, most of the disease burden in most patients was stable or partially responded to enzalutamide. “Progression” often consisted of a relatively small proportion (< 10%) of the overall disease burden. However, some patients also exhibited early, widespread progression. The point here is that binary definitions of progression have trouble distinguishing between the former and the latter. Many patients with true oligoprogression may benefit from ablative local therapy and the continuation of anti-androgen therapy.TBL: Methods of identifying men with heterogeneous mCRPC progression might extend the clinical benefit of anti-androgen therapy beyond the time of initial progression. | Kyriakopoulos, J Clin Oncol 2020