Risk stratification in oligometastatic prostate cancer: where are we and what do we need?

The oligometastatic disease state was initially described over 20 years ago as an 'intermediate' stage in metastatic cancer progression potentially amenable to curative treatment. Interest in identifying men with oligometastatic disease that may be cured has been increasing. However, whether there truly is a distinct oligometastatic state requires prospective validation, and a risk stratification system based on clinical and genomic factors is needed.

We reviewed the existing literature, including 11 ongoing prospective clinical trials, defining the oligometastatic state. We identified specific areas of need including ensuring consensus on the definition of oligometastatic disease and identifying the optimal imaging modality for oligometastatic disease. We identified clinical factors associated with disease aggressiveness in the hormone sensitive metastatic setting, but clinical and molecular risk factors for the oligometastatic setting remain undefined.

Although risk prediction systems for men with oligometastatic prostate cancer are currently lacking, ongoing interest in this disease state and current clinical trials prospectively assessing biologic relevance, optimal imaging, treatment approaches, and predictive markers, including genomic classification, will provide the data necessary to develop a clinically relevant risk stratification system for the oligometastatic disease state.