Oligometastatic Solid Tumors: Disease Characteristics and Role of Local Therapies

Abstract

Background: Treatment recommendation and benefit of local therapy in oligometastatic disease (OMD) are an era of interest and debate. However, most of the clinical literature on OMD is cancer site specific. Objective: To study OMD detailed disease characteristics and outcomes regarding local therapies. Patients sand methods: This observational prospective cohort study included 234 patients with stage IV solid tumors who met the criteria of OMD (≤ 5 metastatic lesions, and or ≤ 2 organs) with performance status 0-2; we studied disease characteristics and outcomes regarding local therapies of OMD. Results: 126 (53.8%) patients received local therapies; surgery, radiotherapy (RT) and local ablative therapy (group I). 108 (46.2%) patients didn't receive local therapy (group II). Comparing both groups, in group I, patients had significantly younger age, earlier initial TNM stage, higher rates of metachronous onset, symptomatic disease, soft tissue disease, single lesion and or single organ involvement and complete response, but lower rates of managed pulmonary OMD compared to group II. Regarding survival, local therapy of OMD was associated with better PFS and OS. The mean OS since OMD diagnosis in local therapy group was 64 months vs. 38 months in non-local therapy patients and the median PFS was not reached in local therapy patients vs. 30 months in no local therapy patients. By multivariate regression analysis, local therapy for OMD was an independent prognostic factor for both progression-free survival (PFS) and overall survival (OS). Conclusions: For selected oligometastatic solid tumor patients, local therapy for OMD could improve PFS and OS.