Oligometastases in Genitourinary Tumors: Recent Insights and Future Molecular Diagnostic Approach

Context: An oligometastatic state is an early event during tumor metastatic spread and is rarely reported in patients with genitourinary tumors. In this condition, the primary tumor has low capacity for distal dissemination because its aggressiveness has not yet reached a maximum. Objective: To review recent findings on the diagnosis and treatment of oligometastatic disease in patients with genitourinary tumors. Evidence acquisition: To identify relevant studies, we reviewed articles in PubMed from January 1966 to September 2017. The search was conducted by combining the words "oligometastasis" or "oligometastatic disease" with "bladder cancer", "genitourinary tumor", "prostate cancer", and "renal cancer". Evidence synthesis: In renal cell carcinoma (RCC), tumors from patients with multiple metastases showed a different gene signature compared to oligometastatic RCC. In addition, an oligometastatic state was an independent prognostic factor for overall survival (OS). Otherwise, the characteristics of oligometastases from bladder cancer remain unclear, as do the clinical and prognostic significance of metastasectomy in this setting. However, patients with oligometastatic prostate cancer have longer recurrence-free survival and OS and seem to benefit from local metastasis-directed therapies. Conclusions: Early detection of oligometastatic disease in patients with genitourinary tumors is fundamental in improving outcomes by identifying patients who would benefit from local approaches with potentially curative rather than palliative intent. Patients with oligometastases in genitourinary tumors show longer survival because of generally lower tumor aggressiveness and potential eligibility for local approaches. Emerging molecular diagnostic techniques will allow early diagnosis of the oligometastatic state and consequently improve patient outcomes.