Suv Max Ratio As A Novel Prognostic Factor In Advanced Colorectal Cancer.

e14520 Background: The clinical utility of fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan predicting the outcome of patients with metastatic colorectal cancer (mCRC) has not been yet well studied. We hypothesized the relationship between standardized uptake value (SUV) FDG-PET scan before and after treatment predicting outcomes among patients with mCRC. Methods: We retrospectively reviewed mCRC patients underwent FDG-PET scan prior treatment and measured metabolic activity in follow-up imaging at the University General Hospital of Ciudad Real (Spain). SUV max Ratio of the main metastatic lesion was calculated (SUV max post treatment / SUV max pre-treatment). Primary end points, time to treatment failure (TTF) and overall survival (OS) were stratified in low and high median SUV max ratio. TTF and OS were estimated by Kaplan Meier method. Survival probabilities were estimated by Cox proportional regression analysis. Results: The study population consisted of 94 patients (median age of 64 years). Median pretreatment SUV was 7,7 (range, 0,6-32,0), median post treatment SUV was 2,2 (range, 0,6-30,9) and the median SUX max ratio was 0,49 (0-4). There were differences in TTF (14 Vs 8 months) and OS (40 Vs 28 months) non statistically significant; but if we can establish a subgroup analysis, patients with metastatic hepatic lesions (N = 58) TTF was 13 Vs 7 months (p < 0.05) and OS was 42 Vs 17 months (p < 0.01); regarding extrahepatic disease (N = 36), no differences were found in OS and TTF rates. SUV ratio in metastases was a significant predictor for overall survival (hazard ratio 0.530, 95% confidence interval 0.282–0.996, P < 0.05). Conclusions: SUV max ratio could be a novel prognostic marker for advanced colorectal cancer patients receiving systemic therapy. Low SUV max ratio was associated with markedly longer OS and longer TTP.