Abstract
Background Liver metastasectomy for colorectal liver metastasis (CRLM) has been found to be associated with higher overall survival in select patients. However, this aggressive surgical treatment option is underutilized. At the county level, there is variation in undergoing surgery for CRLM that is associated with county-level poverty rates. However, in contrast, county-level variation in odds of undergoing surgery for stage I colorectal cancer (CRC) was not associated with county-level poverty rates. The objective of this study was to evaluate the impact of distance traveled as a barrier to surgery for CRLM compared to its impact on surgery for stage I CRC. Methods We previously used the Surveillance, Epidemiology, and End Results Research Plus (SEER) database to perform an ecological, cross-sectional, and county-level analysis of the county-level proportion of patients with CRLM diagnosed between January 1, 2010, and December 31, 2018, and as a comparator group, we included county-level proportion of patients with stage I CRC. In this study, we mapped out the variation in receiving surgery for CRLM or for stage I CRC that exists in states that contribute data to SEER. We also evaluated the correlation between the driving distance in miles from the center of a county to the closest National Cancer Institute (NCI) designated cancer center or Commission on Cancer (CoC) accredited cancer program and proportion of patients with CRLM and stage I CRC who received surgery at the county level. Results A total of 191 counties were included, and these included counties in which residing patients had access via land travel to an NCI-designated cancer center or CoC-accredited cancer program. Counties that had high rates of surgery for CRLM had the shortest distance to the nearest NCI-designated cancer center (63.1 and 46.5 miles, respectively). The distance to the nearest NCI-designated cancer center significantly differed between counties that were discordant and favored CRLM surgery and counties that were concordant and low for both CRC and CRLM surgery (p=0.02). The median distance to the nearest NCI-designated cancer center ranged from 46.5 miles to 114.5 miles among these four groups of categorized counties. Including the 25(th) and 75(th) percentiles, these traveling distances ranged from 25.8 miles to 218.3 miles. Conclusion Counties with high rates of surgery for CRLM did have the shortest distances to the nearest NCI-designated cancer center. Although median traveling distances to the nearest NCI-designated cancer center were potentially prohibitive, they did not fully explain differences in county-level surgical rates.