Complete metastasectomy is expected to improve the survival of patients with metastatic renal cell carcinoma (mRCC). However, many patients develop re-recurrence, despite achieving complete remission with surgery. We examined recurrence-free survival (RFS) and analyzed predictive factors for recurrence after complete metastasectomy.
Fifty-one patients with mRCC who underwent complete metastasectomy between 2008 and 2018 were included in this study. Multivariate Cox regression analyses were performed to identify the prognostic factors for RFS.
Of 51 patients, 6 (12%) had multiple metastatic sites and 45 (88%) had solitary metastasis. The pathological subtype was clear cell in 42 (82%), papillary in 8 (17%), and other subtype in 1 (2%) patient. Sarcomatoid features were found in 2 (4%) patients. The Memorial Sloan Kettering Cancer Center risk category was favorable in 43%, intermediate in 53%, and poor in 4% of patients. The median duration from nephrectomy to metastasectomy was 32 months. Of the total cohort, 39 patients (74%) developed recurrence after complete metastasectomy. The median RFS was 22 months, and the 2- and 5-year RFS rates were 45% and 25%, respectively. Multivariate Cox regression revealed that ≥2 metastatic sites (vs. 1 site; HR = 4.52; P = 0.024) and sarcomatoid features (HR = 11.5; P = 0.0171) were independent predictive factors for recurrence. The 2- and 5-year cancer-specific survival rates were 98% and 82%, respectively.
The number of metastatic sites and sarcomatoid features were associated with recurrence after complete metastasectomy, which suggests that careful observation is required for such patients, even after achieving complete remission with metastasectomy.

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