Resistin and interleukin 6 as predictive factors for recurrence and long-term prognosis in renal cell cancer.

OBJECTIVES: The aim of the present study was to investigate prognostic factors for long-term outcome of renal cell cancer (RCC) in a cohort of patients treated before new antiangiogenic therapy modalities were introduced. Our specific aim was to explore resistin and interleukin 6 (IL-6) levels to find out cytokines potential to predict recurrence and survival in patients with RCC.

MATERIALS AND METHODS: Our prospective study population consisted of 91 patients who underwent radical nephrectomy or partial resection for RCC at Tampere University Hospital between 1994 and 2001. At the time of surgery, 25 patients were diagnosed to have an advanced tumor and 66 patients a local tumor; 34 patients in the latter group developed a recurrence during the follow-up period of 15 years. Serum samples were collected preoperatively and at 3, 9, and 15 months and at 2, 3, 4, and 5 years postoperatively. IL-6 and resistin levels in serum were measured by immunoassay.

RESULTS: Preoperative values of IL-6 (P = 0.006) and resistin (P<0.001) were higher in patients with advanced RCC when compared to patients with local tumors. Patients with local RCC who developed a recurrence during the follow-up period had higher preoperative IL-6 values (P = 0.003) than patients without a recurrence. Based on trajectory analysis of IL-6 and resistin levels, the patients were divided into 3 trajectory groups. According to multivariate analysis, the patients in the trajectory class of the increasing resistin values during the follow-up period had a statistically significantly higher risk for RCC progression (hazard ratio [HR] = 3.73, 95% CI: 1.52-9.13) and for poor survival (HR = 4.93, 95% CI: 1.79-13.6) than the patients in the lowest trajectory class. Furthermore, the patients in the trajectory class of the highest IL-6 values showed a significantly elevated risk for RCC progression (HR = 7.03, 95% CI: 3.00-16.5) and for RCC-related poor survival (HR = 6.09, 95% CI: 2.53-14.7), when compared to the patients in the trajectory class of the lowest IL-6 values.

CONCLUSION: In patients with RCC, the elevated preoperative resistin levels associated strongly with an advanced disease. Based on Cox regression models and trajectory analysis, resistin values were associated with disease progression and a poor survival.