J. B. Meier1,2, G. Murimwa1, P. Polanco1 1University Of Texas Southwestern Medical Center, Department Of Surgery, Dallas, TX, USA 2VA North Texas Health Care System, Department Of Surgery, Dallas, TX, USA
Introduction:
Colorectal cancer (CRC) mortality is amenable to healthcare access and treatment, which is affected by social determinants of health. While prior studies have identified individual disparities in cancer care and survival, the social vulnerability index (SVI) has not been previously used to compare healthcare access and survival in colorectal cancer patients or if that differs according to patient age. We hypothesized that there would be census tract-level disparities in colorectal cancer access to treatment and mortality, especially in patients less than 65 years who may be particularly sensitive to social determinants of health.
Methods:
We queried the Texas Cancer Registry from 2004-2019 to identify those with localized (early stage) CRC and further categorized patients into <65 years and ≥65 years. Our primary outcomes were survival and access to surgical intervention. The primary independent variable of interest was census tract SVI, with higher scores indicating more social vulnerability. We used chi square analysis, Wilcoxon Rank Sum Test, multivariable logistic regression, and Cox proportional hazards to compare outcomes.
Results:
In total, we included 28,863 patients with localized CRC with a median age of 68 years (IQR 58-78) and 11,321 (39.2%) less than 65 years. Overall median social vulnerability index percentile was 55.3 (28.3-77.4). Older patients were less likely to be alive at 5 years (52.4% vs 70.7%, p<0.0001) and there was not a difference in resection rates between older and younger patients (88.0% vs 88.3%, p=0.4), however, older patients tended to live in census tract with higher social vulnerability (55.6 percentile vs 53.2 percentile SVI, p<0.0001).
On multivariable analysis within those less than 65 years, increased SVI was associated with increased risk of death at 5 years (HR 1.22, 95% CI 1.03-1.43, p=0.02) as well as decreased odds of surgical intervention (OR 0.76, 95% CI 0.57-0.99, p=0.04). This was primarily driven by housing/transportation and socioeconomic themes within the SVI. However, in older patients, social vulnerability was not associated with either death (HR 1.07, 95% CI 0.97-1.18, p=0.2) or receipt of surgical intervention (OR 0.92, 95% CI 0.75-1.14, p=0.4).
Conclusion:
Although 5-year survival was better in younger patients, likelihood of lack of surgical treatment and death in this group was more sensitive to social factors. Although this study is limited to a select group of patients in a single state, it highlights the association of social factors on colorectal cancer treatment and survival. These findings amplify the need for policy changes at the local, state, and federal level to increase access to surgical care and reduce amenable mortality in population at risk.