FDG-PET for prediction of survival of patients with metastatic colorectal carcinoma

Background: The current study focuses on the prognostic value of pretreatment metabolic activity in metastases as measured with [F-18]fluorodeoxyglucose positron emission tomography (FDG-PET), as an indicator of survival in colorectal cancer. Patients and methods: In a prospective series of 152 patients with metastatic colorectal cancer, of whom 67 were treated with resection of metastases and 85 with chemotherapy, standardized uptake values (SUV) as measured with FDG-PET, were calculated prior to treatment. Survival probabilities were estimated by Cox proportional regression analysis. For Kaplan-Meier analysis SUV was stratified by the median value. Survival differences were assessed using the log-rank test. Results: SUV in metastases was a significant predictor for overall survival (hazard ratio 1.17, 95% confidence interval 1.06-1.30, P = 0.002), independent of the subsequent treatment. According to the median value of the patient population a low (SUV < 4.26) and high uptake group (SUV > 4.26) was defined. The median survival and the 2- and 3-year survival rates were 32 months, 59% and 45%, respectively, in the low-uptake group and 19 months, 37% and 28%, respectively, in the high-uptake group (P = 0.017). Conclusion: A significant survival benefit was observed in patients with low FDG uptake in metastases of colorectal cancer.