Systematic classification and prediction of complications after nephrectomy in patients with metastatic renal cell carcinoma (RCC)

Study Type - Harm (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Radical nephrectomy for patients with metastatic renal cell carcinoma results in greater rates of morbidity than for those with less advanced disease. This study systematically characterizes complications associated with nephrectomy for metastatic RCC and identifies patient and disease characteristics that are associated with a greater risk of developing complications. Overall complications were relatively frequent, but major complications (grade 3 or greater) were rare. Increasing age and worsening performance status were associated with increased probability of complications. When complications were sustained, patients were less likely to receive systemic therapy in a timely fashion. These observations may influence the timing or patient selection for surgery or systemic therapy. Objective: To evaluate and identify factors predictive for morbidity after radical nephrectomy in patients with metastatic renal cell carcinoma (mRCC). Patients and Methods: We identified patients with mRCC who underwent nephrectomy at Memorial Sloan-Kettering Cancer Center (MSKCC) between 1989 and 2009. Postoperative complications were characterised using a modified version of the Clavien-Dindo classification system. Patient and disease characteristics, including a previously validated MSKCC risk-stratification system using calcium, haemoglobin (Hb), lactate dehydrogenase, and Karnofsky Performance Status (KPS), were evaluated as predictors of postoperative complications using univariate and multivariable logistic regression models. The area under the receiver operating characteristic curve (AUC) was calculated for each model to assess predictive accuracy and corrected for overfit using 10-fold cross validation. Results: Over the study period, 195 patients with mRCC underwent nephrectomy; 53 (27%) developed grade ≥2 complications within 8 weeks of surgery. Pulmonary, thromboembolic events and anaemia requiring transfusion were the most common types of complications after nephrectomy in the metastatic setting. In univariate analysis, age, low albumin, low KPS, high corrected serum calcium, low serum Hb, and unfavourable MSKCC risk score were predictive of complications. Patients who sustained postoperative complications were less likely to receive systemic therapy within 56 days (odds ratio [OR] 0.32; 95% confidence interval [CI] 0.12-0.86; P= 0.024). A multivariable model containing KPS (OR 14.5; 95%CI 4.34-48.6; P < 0.001) and age (OR 1.04; 95%CI 1.01-1.08; P= 0.014) showed the greatest predictive accuracy (corrected AUC 0.72; 95%CI 0.63-0.80) for postoperative complications. Conclusions: Postoperative complications after radical nephrectomy in the setting of mRCC are common and occur frequently in older patients and those with worse KPS. These complications are important because they may delay or deny receipt of subsequent systemic therapy.