Clinical colorectal cancer (CRC) subsets in advanced disease: Patterns of metastatic spread to predict survival.

Abstract

e14703 Background: Advanced CRC is a heterogeneous disease. Some patients exhibit diffuse metastatic spread while others show selective organ involvement. We aimed to investigate the frequency and survival implications of initial pattern of metastatic spread in a Mexican cohort. Methods: We retrospectively reviewed charts and radiologic images of patients with advanced CRC at our institution from 2004 to 2011. The initial pattern of spread was recorded. Categories depending on the predominant site of involvement were: 1) Locally advanced, 2) Hepatic, 3) Pulmonary, 4) Peritoneal or 5) Diffuse. Survival was estimated by the Kaplan Meier method and Log rank test used to determine survival differences among categories. Results: 179 patients with advanced CRC were identified. Median age was 60yo, 56% were male. Primary tumor location was 50.3% colon, 27.9% rectum, 17.9% recto-sigmoid and 3.4% had synchronous disease. 66% of patients had advanced disease at diagnosis and 34% were recurrent cases. Metastasis at diagnosis involved the liver in 105 (58.7%), peritoneum in 49 (27.4%), lung in 56 (31.3%) and non regional lymph nodes in 36 (20.1%) patients. Notably, 101 (56%) patients had a predominant site of metastatic involvement: locally advanced in 3 (1.7%), hepatic in 51 (28.5%), peritoneal in 21 (11.7%), pulmonary 21 (11.7%) while 78 patients (44%) had disseminated disease. Median overall survival was 15 months (n= 179) and differed according to predefined CRC subsets: 9, 13, 22, 23, and 52 months for peritoneal, disseminated, hepatic, locally advanced and pulmonary spread respectively p=.018 (significant after multivariate analysis). Other factors associated with better survival were female gender p=.040, absence of morbidity from primary tumor p=.27, resection of primary tumor p=.004, recurrent presentation p=.039, and access to 1stline chemotherapy p=.00. Conclusions: Over 50% of patients exhibited selective metastatic spread. Clinically defined subsets correlate with better (pulmonary) or worse (peritoneal/disseminated) survival. This finding might have implications in patient selection for regional therapies and encourage research to find the molecular determinants of this biologic behavior.