The effect of metastasectomy on overall survival in metastatic renal cell carcinoma: A systematic review and meta-analysis.

PURPOSE Metastasectomy (MTS) is a treatment option for patients diagnosed with metastatic Renal Cell Carcinoma (mRCC). Nevertheless, the benefits of MTS as they pertain to survival remain controversial. This systematic review aims to compare the survival outcomes of patients who underwent MTS, as well as discover which clinical factors were related to the results. METHODS From their inception up to August 2020, a systematic review of the EMBASE, PubMed, Cochrane library, and Web of science databases was performed. Studies which reported outcomes on patients who underwent MTS for the treatment of mRCC were included. The sites, times, amount, histology types of metastasis, and prior nephrectomy were also analyzed. The primary efficacy end point was Overall Survival (OS). A meta-analysis was performed to calculate hazard ratio, 95% confidence intervals, and I2 values. Forest plots were constructed for each analysis group. RESULTS The systematic review and reference list search identified 294 articles, with 17 meeting studies as inclusion criteria. The MTS group showed a competitive advantage in OS, in that the non-MTS group was negatively associated with an overall survival rate (HR [non-MTS vs. MTS] = 2.15, 95% CI: 1.59-2.92, P< 0.001). Moreover, patients treated with the most recently available target therapy without MTS showed a significantly increased risk compared with the MTS group (HR = 1.82, 95% CI:1.23-2.70, P= 0.003). Additionally, meta-analysis revealed HR elevating in patients with nonlung only metastasis (HR = 1.87, 95% CI: 1.55-2.26, P< 0.001), synchronous metastasis (HR = 1.28, 95% CI: 1.10-1.49, P= 0.001), and multiple metastases (HR = 2.06, 95% CI: 1.64-2.59, P< 0.001). Clear-cell type mRCC (HR = 0.62, 95% CI: 0.48-0.82, P= 0.0006) and prior nephrectomy (HR = 0.37, 95% CI: 0.15-0.91, P= 0.03) were positively associated with a better overall survival rate. CONCLUSIONS MTS is a treatment option for mRCC patients with prolonged overall survival time. The operation has additional advantages, particularly in patients with lung only metastasis, asynchronous metastasis, fewer metastasis sites, clear-cell type mRCC, and the patients who had received nephrectomy.