Survival differences in patients with metastatic colorectal cancer and with single site metastatic disease at initial presentation: results from South Australian clinical registry for advanced colorectal cancer

Background: Colorectal cancer is the third most common cancer in Australia. The median overall survival for metastatic colorectal cancer is nearly 2 years. However, there may be survival differences based on site of metastatic disease. Methods: Data was collected from the South Australian Registry for Advanced Colorectal Cancer. A total of 1207 patients with single site metastatic disease at initial diagnosis were subclassified into 6 subgroups: liver only (n = 780), pelvic only (n = 148), lung only (n = 142), lymph node only (n = 95), bone only (n = 32), and brain only (n = 10). Univariate and multivariate parametric survival analyses were performed. Results: Median overall survival was 20.3 months for the whole group. The overall survival for lung-only metastases group was 41.1 months followed by liver- and pelvic-only disease groups (22.8 and 23.8 months, respectively). Patients with isolated bone-only and brain-only metastases had poor overall survival (5.1 and 5.7 months, respectively). On multivariate analysis, prognosis was superior for the lung-only group. Conclusions: Lung only group had the longest median overall survival. Bone and brain sites had a poor outlook. Site of metastatic disease at initial presentation may be prognostic.