Pathological Response and Outcomes in Patients With Metastatic Renal Cell Carcinoma (mRCC) Receiving Immunotherapy-Based Therapies and Undergoing Deferred Cytoreductive Nephrectomy (CN).

ABSTRACT

In this study we evaluated outcomes of patients with metastatic renal cell carcinoma who received immunotherapy before surgery. We found that receiving immunotherapy combinations before surgery can offer patients benefits in reducing tumor size and improving disease control. BACKGROUND: Immunotherapy (IO) has improved outcomes for patients with metastatic renal cell carcinoma (mRCC). However, the timing of surgical intervention for cytoreductive nephrectomy (CN) is still controversial for this group of patients. PATIENTS AND METHODS: We identified patients with mRCC receiving IO-based therapies and undergoing CN. Patients were divided into 2 cohorts those who underwent upfront CN and those who underwent deferred CN. Pathologic and radiographic features along with clinical outcomes were systematically collected. Comparisons were performed using Chi-square test, paired t-Test or Mann-Whitney-U test. Progression Free survival (PFS) and Overall Survival (OS) were estimated using the Kaplan-Meier method. RESULTS: Fifty-one patients with mRCC were included, with a median follow-up of 21 months. 38 (74.5%) patients received IO-based therapies prior to CN, while 13 (25.5%) patients underwent up-front CN. IO-based therapies reduced median tumor size from pretreatment 10 cm to 8.6 cm post-treatment when given prior to CN. IO-TKI had a trend toward higher tumor shrinkage (-2.3 vs -1.2 cm). Pathologic T downstaging occurred in 42% (n=16) of patients, 11% (n=4) of whom had pT0 disease. Thrombus downstaging occurred in 13% (n=6) of patients, all with either partial response (PR) or complete response (CR) in metastases. PFS (HR=0.7, 95% CI 0.29-1.98, p=0.58) and OS (HR 0.4, 95% CI 0.13-1.57, p=0.21) were not statistically significant between 2 cohorts. CONCLUSIONS: IO-based therapies, particularly IO-TKIs, resulted in pathologic necrosis and reductions in tumor size prior to deferred CN. PFS and OS were similar for patients who received either upfront IO-based therapy or after CN.