574PRISK OF RECURRENCE IN PATIENTS WITH COLON CANCER STAGE II AND III: A SYSTEMATIC REVIEW OF RECENT LITERATURE

Abstract Aim: Adjuvant chemotherapy is established routine therapy for colon cancer (CC) patients with radically resected stage III and “high-risk” stage II disease. The decision on recommending adjuvant chemotherapy, however, is based on data from older patient cohorts not reflecting improvements in pre-operative staging, surgery, and pathological examination. The aim of this study is to review the current risk of recurrence in stage II and III patients adequately staged, operated by colorectal cancer specialized surgeons, the surgical specimen investigated according to modern standards, and adequately followed-up, and secondly, to estimate the relative importance of routinely assessed clinico-pathological variables. Methods: The PubMed/MEDLINE and the Cochrane databases were systematically searched for randomized controlled studies and observational studies published after 1.1.2005 with patients included after January 1995 on prognosis in surgically treated patients with CC stage II and III. Results: Of 2596 studies identified, 37 met the inclusion criteria and 25 provided data for meta-analysis. The total patient sample size in the 25 studies reporting either disease-free or recurrence-free survival (DFS) was 15,785 in stage II and 18,425 in stage III. Five-year DFS for stage II patients operated without subsequent adjuvant chemotherapy was 81.4% (95% confidence interval (CI) 75.4-87.4; in studies with good/very good quality of reporting it was 82.7%, (95%CI 80.8-84.6)), and for stage III 49.0% (95%CI 23.2-74.8). For stage II patients treated with adjuvant chemotherapy, the 5-year DFS was 79.3% (95%CI 75.6-83.1), and for stage III 63.6% (95%CI 59.3-67.9). The prognostic impact of commonly investigated clinico-pathological parameters, i.e. pT-stage, pN-stage, differentiation, number of lymph nodes studied, MMR-status, and emergency surgery was confirmed. Conclusions: There are several reasons to regard the presented DFS results as an under-estimation of what is achieved at high-quality centres today. The effects of ongoing efforts towards optimized patient management on recurrence rates should be further evaluated in prospective population-based studies, and the results published Disclosure: All authors have declared no conflicts of interest.