Incidence and clinical relevance of paraneoplastic syndromes in patients with renal cell carcinoma.

Background: Paraneoplastic syndromes (PNS) are defined as the signs and symptoms attributed to cytokines or hormones released from a tumor or a patient's immune system. PNS have been reported with many cancers for decades and data supporting their relevance in renal cell carcinoma (RCC) are largely historical. The widespread use of electronic medical record (EMR) systems provides a more robust method to capture data. The objective of this study was to establish contemporary data regarding the incidence and relevance of PNS in patients undergoing nephrectomy for suspected RCC.

Methods: In this retrospective single-institution study, 851 patients undergoing nephrectomy for suspected RCC between 2011 and 2018 were assessed for the presence or absence of PNS as defined by laboratory abnormalities. Factors associated with PNS and with all-cause mortality were examined.

Results: The incidence of PNS was 33.1% among 851 patients prior to nephrectomy. The most prevalent PNS were anemia (22.4%), thrombocytosis (7.5%), and elevated C-reactive protein (CRP) (7.4%). PNS were more common in women (39.2% vs. 29.4%, p = 0.0032) and higher stage RCC (31.1% of stage I vs. 54.2% of stage IV, p = 0.0036). Factors associated with the presence of PNS in multivariable analysis included female gender, high comorbidity, and stage IV RCC. Prenephrectomy PNS were associated with poorer survival in multivariable analysis (HR: 2.12, p = 0.0002). Resolution of PNS occurred in 52.1% of patients after nephrectomy, including 55.2% with stage I to III and 38.5% with stage IV RCC (p = 0.10).

Conclusions: Using EMR data, laboratory evidence of PNS was present in one-third of a contemporary cohort of patients undergoing nephrectomy, with >50% of PNS resolving after surgery. Consistent with prior reports, PNS are more common in higher-stage RCC and are associated with poorer survival in RCC patients.