Cancer survival for rural and urban populations during the opioid epidemic: A SEER analysis.

Abstract

e23065 Background: The opioid epidemic has disproportionately affected rural communities, with associated increases in overdose deaths, non-overdose medical mortality and healthcare costs. Few studies, however, have evaluated changes in cancer related mortality in the rural communities most affected by the opioid epidemic. Methods: We analyzed cause-specific five-year survival data for prostate, breast, colorectal, pancreatic, lung, and liver cancers diagnosed from 2000-2016 using the SEER Database (22 registries covering 48% of the US population). Rural and urban residence was defined using USDA Rural-Urban Continuum Codes. Ordinary least squares regression assessed temporal survival trends, and analysis of covariance compared the statistical significance in annual change in survival between rural and urban groups. Results: We created a cohort of 2.96 M people with cancer including 5 of the most commonly diagnosed cancers between 2000 and 2016. The cohort included 93% urban and 7% rural people with cancer and was 78% white and 22% non-white. There were significant differences in demographics between urban and rural patients in all cancer types. Five-year survival improved over time for all cancers except prostate; however, gains were consistently inferior for rural compared to urban populations. Rural-urban differences in survival were present at year 2000 and widened by 2016 for breast (1.8% to 2.9%), colorectal (2.1% to 3.0%), pancreatic (0.2% to 4.2%), lung (2.5% to 8.7%) and liver cancer (2.1% to 14.0%). We compared the rate of change in cancer mortality between rural and urban populations and found significant differences in all of cancers (p<0.05) except for prostate cancer (p=0.57). Conclusions: From 2000 to 2016, rural-urban disparities in cancer survival widened for five of six major cancers. Over the same period, national opiate overdose rates increased in rural populations and then exceeded urban populations. Consistent with previous studies showing increases in non-overdose related mortality in populations with higher opioid exposure, our study confirms widening disparities between urban and rural populations across a broad range of cancers. These findings warrant additional efforts to understand the root causes of widening disparities for rural patients with cancer. Cause-specific 5-year survival difference (urban - rural) and difference in ordinary linear regression slopes. Urban Rural Difference in year 2000 Urban Rural Difference in year 2016 Change from 2000 to 2016 Average Yearly Change in Difference (slope of difference) Prostate 2.5% 2.6% 0.10% 0.04 Breast 1.8% 2.9% 1.10% 0.12 * Colorectal 2.1% 3.0% 0.90% 0.15 * Pancreas 0.2% 4.2% 4.00% 0.19 * Lung 2.5% 8.7% 6.20% 0.38 * Liver 2.1% 14.0% 11.90% 0.48 * *p<0.05 determined by ANCOVA assessing the significance of the difference in slopes between the urban and rural groups.