Colorectal cancer presenting as bone metastasis

Introduction: Bone metastasis is a rare site of metastasis, seen in only 3.7-11% of clinical cases. Isolated bone involvement has been reported very rarely in literature. Moreover, the patients who have bone metastasis at presentation are even rare. Objectives: To discuss the demographic characteristics, carcinoembryonic antigen (CEA) levels, pattern of bone involvement, and their correlation with survival in patients of colorectal cancer that have bone metastasis at the time of presentation. Materials and Methods: Retrospectively, tumor registry was analyzed for the cases of colorectal cancer presenting with bone metastasis between 2008 and 2013. Survival curves were generated by Kaplan-Meier method and analyzed using the log-rank test. Results: Ten such patients were identified (male: female = 7: 3) of the total 410 patients. Median age was 41 years (22-50 years). All patients were < 50 years of age. Median CEA level was 147.5 (45-840). Three patients had bone-only metastasis. Most common metastatic site involved was liver (six patients) and lungs (three patients). The most common sites of bone metastasis were vertebra and pelvis (4 each). Chemotherapy was given in seven patients. Median overall survival was 5.5 months (2-36 months). It was higher in males, in those with bone-only involvement and those without liver involvement. Vertebral involvement, pelvic involvement, CEA levels, and chemotherapy did not show any significant survival implication. Conclusions: In this study, the patients of colorectal cancer presenting with bone metastasis were of male sex and younger age. The factors that were associated with reduced survival were extraosseous and liver involvement.