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

There may be differences in overall survival in patients with metastatic colorectal cancer based on the site of metastatic disease at the time of initial presentation. Our research showed that median overall survival was longer for the lung-only disease group and bone-only and brain-only sites had a poor outlook. 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.