Abstract
BACKGROUND: Colorectal cancer is one of the most common malignancies in the Western world, and is responsible for about 10% of annual cancer-related deaths. Especially for UICC stage IV, the probability of survival is significantly reduced. Little is known about risk factors for specific metastatic patterns of colorectal cancer that may also influence patients' overall survival. METHODS: We used data from the IQVIA oncology dynamics (OD) database to determine the prevalence of pulmonary metastases in 19,321 patients with UICC stage IV colorectal cancer in eight European and Asian countries. RESULTS: In total, 6132 of 19,321 (31.7%) study patients had lung metastases, with a higher prevalence among patients with rectal (37.5%) than colon (30.1%) cancer. When compared to China as the country with the lowest lung metastases prevalence, the odds for lung metastases were highest in UK (OR: 2.02, 95%CI: 1.80-2.28), followed by Italy (OR: 1.86, 95%CI: 1.52-2.27), Spain (OR: 1.85, 95%CI: 1.64-2.09), and Germany (OR: 1.47, 95%CI: 1.26-1.71). CONCLUSION: The prevalence of pulmonary metastases in UICC stage IV colorectal cancer varies widely among the different analyzed countries. Although the present data are purely descriptive, a possible combination of ethnic, environmental, and health care system-associated differences could be discussed as the underlying cause. Further studies are needed to investigate the reasons for differences in the prevalence of lung metastases.