Pulmonary metastasectomy in renal cell carcinoma: Predictive and prognostic elements from paired histopathological analysis of primary tumors and respective metastases

Abstract

Objective: To identify histopathological and immunophenotypical features with potential predictive or prognostic value in patients undergoing pulmonary metastasectomy from renal cell carcinoma (RCC). Methods: We retrospectively collected all consecutive patients undergoing pulmonary metastasectomy from RCC after prior nephrectomy. Paired samples of primary tumors and corresponding pulmonary metastases were analyzed, revising histopathological features and testing C-MET, mTOR, and PD-L1 by immunohistochemistry. Results: A total of 25 patients were included. Median overall survival (mOS) from metastasectomy was 5.5 years (95% CI = 1.9–9.1). The laterality of metastases had a significant predictive value, with median relapse-free survival (mRFS) from metastasectomy not reached (NR) at mean follow-up (FU) of 60.8 months for left lung involvement, mRFS of 52.9 months (95% CI = 0–145.5) for the right lung and 6.4 months (95% CI = 1.7–11) for bilateral metastases ( p = 0.028). Primary RCC with positive expression of mTOR had higher mOS after metastasectomy than negative cases ( p < 0.001), NR at mean FU of 4.3 years versus mOS of 2 years (95% CI = 0.7–3.3), respectively. PD-L1 positivity on intra-tumor (TILs) and peri-tumor (RILs) infiltrating lymphocytes of metastases was related to higher OS, NR versus 2 years (95% CI = 1.2–2.7, p = 0.003), and NR versus 1.4 years (95% CI = 0.2–2.6, p = 0.012), respectively. The shorter was the surgical interval, the more probably the metastases had high c-MET expression (>70%) ( p = 0.007) and PD-L1 expression >10% on TILs ( p = 0.024). Conclusions: mTOR positivity on primary RCC could be a favorable prognostic factor to select patients for pulmonary metastasectomy. The positive impact of PD-L1 expression on immune cells is opposite to the well-known negative prognostic value of PD-L1 on tumor cells in RCC.