Can urologists introduce the concept of "oligometastasis" for metastatic bladder cancer after total cystectomy?

We investigated whether the concept of oligometastasis may be introduced to the clinical management of metastatic bladder cancer patients. Our study population comprised 128 patients diagnosed with metastatic bladder cancer after total cystectomy at our 6 institutions between 2004 and 2014. We extracted independent predictors for identifying a favorable. Occurrence that fulfilled all 4 criteria which were independently associated with cancer-specific death was defined as oligometastasis: a solitary metastatic organ; number of metastatic lesions of 3 or less; the largest diameter of metastatic foci of 5cm or less; and no liver metastasis. We evaluated differences in clinical outcomes between patients with oligometastasis (oligometastasis group) and those without oligometastasis (non-oligometastasis group). Overall, there were 43 patients in the oligometastasis group. The 2-year cancer-specific survival rate in the oligometastasis group was 53.3%, which was significantly higher than that in the non-oligometastasis group (16.1%, p<0.001). A multivariate analysis revealed that non-oligometastasis (p<0.001), not performing salvage chemotherapy (p<0.001), and not performing metastatectomy (p=0.028) were independent risk factors for cancer-specific death. In the subgroup of 83 patients who received salvage chemotherapy, 30 were in the oligometastasis group. The 2-year cancer-specific survival rate in the oligometastasis group was 55.0%, which was significantly higher than that in the non-oligometastasis group (22.0%, p=0.005). Non-oligometastasis (p=0.009) was the only independent risk factor for cancer-specific death. We presented that urothelial carcinoma with oligometastasis had a favorable prognosis and responded to systemic chemotherapy. Oligometastasis may be treated as a separate entity in the field of metastatic urothelial carcinoma.