Preoperative serum docosahexaenoic acid level predicts prognosis of renal cell carcinoma.

The recent discovery and clinical development of targeted agents have expanded treatment options in metastatic renal cell carcinoma (RCC). However, metastatic RCC remains a lethal disease. Complete response is rare and treatment with targeted agents eventually fails in the majority of the patients. Therefore, there is a need for developing a prognostic tool and a novel therapeutic agent for RCC to improve the follow-up strategy after surgical treatment. Clinical data, including patient characteristics, serum fatty acid profile, clinicopathological parameters and clinical outcome, were obtained from 112 patients with RCC prior to surgical treatment. Preoperative fatty acid levels were grouped according to patient characteristics, such as performance status, body mass index or pathological parameters, and were analyzed using the Mann-Whitney U test. Cancer-specific survival in the high and low docosahexaenoic acid (DHA) level groups were compared using the Kaplan-Meier method. Cox proportional hazards models were applied to determine the independent prognostic factors associated with shortened cancer-specific survival. The serum DHA level in patients with metastasis was significantly lower compared with that in patients without metastasis (P=0.047). Low serum DHA level, presence of metastasis and cachexia were independent predictors of shortened cancer-specific survival in a multivariate Cox proportional hazard model (P=0.033, hazard ratio = 4.43). Patients with a serum DHA level below the median value exhibited significantly shorter cancer-specific survival compared with those with a higher serum DHA level (P=0.008). Thus, according to our results, the preoperative serum DHA level may be able to predict the surgical outcome of RCC. However, this finding requires validation by large-scale prospective studies.