Better survival in patients with metastasised kidney cancer after nephrectomy: A population-based study in the Netherlands
Aim: Cytoreductive nephrectomy is considered beneficial in patients with metastasised kidney cancer but only a minority of these patients undergo cytoreductive surgery. Factors associated with nephrectomy and the independent effect of nephrectomy on survival were evaluated in this study. Methods: Patients were selected from the population-based cancer registry and detailed data were retrieved from clinical files. Factors associated with nephrectomy were evaluated by logistic regression analyses. Cox proportional hazard regression analysis was performed to evaluate factors associated with survival; a propensity score reflecting the probability of being treated surgically was included in order to adjust for confounding by indication. Results: 37.5% of 328 patients diagnosed with metastatic kidney cancer between 1999 and 2005 underwent nephrectomy. Patients with a low performance score, high age, ≥2 comorbid conditions, ≥2 metastases, low or high BMI, weight loss, elevated lactate dehydrogenase, elevated alkaline phosphatase, female gender and liver or bone metastases were less likely to be treated surgically. Three year survival was 25% and 4% for patients with and without nephrectomy, respectively (p < 0.001). After adjustment for other prognostic factors including the propensity score, nephrectomy remained significantly associated with better survival (Hazard ratio: 0.52, 95% Confidence interval: 0.37-0.73). Conclusions: Even after accounting for prognostic profile, patients still benefit from a nephrectomy; an approximately 50% reduction in mortality was observed. It is, therefore, recommended that patients with metastasised disease receive cytoreductive surgery when there is no contraindication. Trial results on cytoreductive surgery combined with targeted molecular therapeutics are awaited for.