High prevalence of deficient mismatch repair phenotype and the V600E BRAF mutation in elderly patients with colorectal cancer.

AIMS: Colorectal cancer (CRC) occurs mostly in the elderly. However, the biology of CRC in elderly has been poorly studied. This study examined the prevalence of deficient mismatch repair phenotype (dMMR) and BRAF mutations according to age. PATIENTS AND METHODS: MMR phenotype was prospectively determined by molecular analysis in patients of all ages undergoing surgery for CRC. BRAF V600E mutation status was analysed in a subset of dMMR tumours. RESULTS: A total of 754 patients who underwent surgery between 2005 and 2008 were included in the study. Amongst them, 272 (36%) were ≥75years old. The proportion of women <75 was 38% and that ≥75 was 53% (p<0.0001). The prevalence of dMMR was 19.4% in patients ≥75 and 10.7% in patients <75 (p=0.0017). For patients ≥75, the prevalence of dMMR was significantly higher in women than in men (27% vs 10.2%, respectively; p=0.003) but was similar in women and men <75 (12.5% vs 9.7%, respectively; p=0.4). We examined BRAF mutation status in 80 patients with dMMR tumours. The V600E BRAF mutation was significantly more frequent in patients ≥75 than in patients <75 (72.2% vs 11.4%, respectively; p<0.001). In patients ≥75, there was no difference in the prevalence of the BRAF V600E mutation according to sex (78% in women and 70% in men, p=0.9). CONCLUSIONS: The prevalence of dMMR in CRC is high in patients over 75. In elderly patients, dMMR tumours are significantly more frequent in women than in men. The BRAF mutation is frequent in elderly patients with CRC.

Primary colectomy in patients with stage IV colon cancer and unresectable distant metastases improves overall survival: results of a multicentric study.

BACKGROUND: Whether patients with stage IV colon cancer and unresectable distant metastases should be managed by primary colectomy followed by chemotherapy or immediate chemotherapy without resection of the primary tumor is still controversial. OBJECTIVE: This study aimed to evaluate predictive factors associated with survival in patients with stage IV colon cancer and unresectable distant metastases. DESIGN: This large retrospective multicentric study included 6 academic hospitals. SETTINGS: This study was conducted at 6 Paris University Hospitals (Assistance Publique-Hôpitaux de Paris; Saint Antoine, Henri Mondor, Ambroise Paré, Hôpital Europeen Gorges Pompidou, Bichat, and Avicenne). PATIENTS: Between 1998 and 2007, 208 patients with good performance status and stage IV colon cancer with unresectable distant metastases received chemotherapy, either as initial management or after primary tumor resection. MAIN OUTCOME MEASURES: Survival was estimated by use of the Kaplan-Meier method. Factors associated with survival were tested by means of a log-rank test. Results were expressed as median values with 95% confidence intervals. Factors independently related to survival were tested using a Cox regression model adjusted for a propensity score. RESULTS: Of the 208 patients, 85 underwent colectomy before chemotherapy, whereas 123 were treated with use of primary chemotherapy with or without biotherapy. At univariate analysis, the following factors were significantly associated with survival: primary colectomy (P = .031), secondary curative surgery (P < .001), well-differentiated primary tumor (P < .001), exclusive liver metastases (P < .027), absence of need for colonic stent (P = .009), and addition of antiangiogenic (P = .001) or anti-epidermal growth factor receptor (P = .013) drugs to chemotherapy. After Cox multivariate analysis and after adjusting for the propensity score, all of these factors, with the exception of two, colonic stent and anti-epidermal growth factor receptor drug, were found to be independently associated with overall survival. LIMITATION: This study was limited by its retrospective nature. CONCLUSIONS: In a selected population of patients with colon cancer and unresectable synchronous distant metastases, immediate colectomy followed by chemotherapy in association with targeted therapy was associated with longer overall survival. This strategy appears to be the most appropriate, especially for those with good performance status, well-differentiated tumors, and synchronous liver metastases only.