P2366 - An Emerging Health Disparity: Early Onset Colorectal Cancer in Appalachia

William K. Oelsner, MD, Aparna P. Shreenath, MD, PhD, Maaz Sohail, MD, Steven Kessler, DO, George Philips, MD, Jensen Hyde, MD, MPH
University of Tennessee Health Science Center College of Medicine, Chattanooga, TN

Introduction: Appalachia is a region that is predominantly rural and encompasses 420 counties in the eastern United States. This region is marked by significant health disparities, poverty, and low life expectancy. Studies have shown that Appalachia has a higher overall incidence of colon and rectal cancer. Recently, parts of Appalachia were identified as hotspots of early-onset colorectal cancer (EOCRC) mortality and decreased survival in men. Nevertheless, regional rates and characteristics of EOCRC for Appalachia are not been well described.

Methods: This retrospective analysis of 86,318 people used the National Cancer Institute (NCI)’s Surveillance, Epidemiology, and End Results (SEER) Program to determine the incidence of EOCRC for non-screening age adults (20 to 49 years) in the United States. The SEER 21 database covers 37% of the US population, including 25% of Appalachian counties. Appalachian Regional Commission’s county designation was used to determine cohort inclusion: 4,727 patients in Appalachian cohort and 81,594 in non-Appalachian cohort. Analysis was conducted using SEER*Stat to calculate rate ratios and 95% CI. Cancer staging and location was compared using Chi-square.

Results: Appalachia was found to have a significantly increased incidence of EOCRC compared to US population. This difference was significant for every 5-year age group from 25 to 45 years of age (p< 0.05, Figure 1). There was no difference for location and Duke CRC Staging between the Appalachian and Non-Appalachian (χ²=0.9116). However, there was a significant difference in histological grade distribution (χ²< 0.0001); moreover, Appalachia was found to have more undifferentiated (Grade IV) cancers (3.49%) than non-Appalachians (2.05%).

Discussion: Appalachia is at-risk for early onset colorectal cancer with significantly increased incidence. This is the first population-based study to describe EOCRC in Appalachia. In 2020, the USPTF began revising the screening guidelines for colon cancer. The current proposal suggests lowering the screening age to 45 years, aligning with the current recommendations by both the American Cancer Society and the American College of Gastroenterology. This study suggests that Appalachia, with its increased incidence of CRC in non-screening age adults, will likely benefit from the new screening age of 45. Furthermore, we advocate further tailoring of guidelines towards at risk geographic areas in addition to demographic populations as is currently the case for those with family history.


Figure: Figure 1: There is an increased incidence of early onset colorectal cancer in Appalachia compared to the US population. Y-error bars represent 95% confidence intervals. Asterix (*) represents age groups that were found to have a significant difference in the incidence of EOCRC between Appalachian and Non-Appalachian Cohorts.

		Non-Appalachian		Appalachian
		n	%	n	%
	Total	81,594	100%	4,724	100%
Age	20-24 years	1,410	1.7%	77	1.6%	Chi Square
	25-29 years	2,952	3.6%	157	3.3%	P=0.3829
	30-34 years	5,896	7.2%	320	6.8%
	35-39 years	11,076	13.6%	684	14.5%
	40-44 years	21,536	26.4%	1,245	26.4%
	45-49 years	38,724	47.5%	2,241	47.4%
Sex	Female	38,971	47.8%	2,241	47.4%	Chi Square
	Male	42,623	52.2%	2,483	52.6%	P=0.6652
Race	White	60,869	74.6%	4,146	87.8%	Chi Square
	Black	12,523	15.3%	442	9.4%	p< 0.0001
	Asian or Pacific Islander	6,603	8.1%	94	2.0%
	American Indian	551	0.7%	9	0.2%
	Unknown	1,048	1.3%	33	0.7%
Ethnicity	Hispanic	12,917	15.8%	196	4.1%	Chi Square
	Non-Hispanic	68,677	84.2%	4,528	95.9%	p< 0.0001

Table: Table 1: Demographics for Non-Appalachian and Appalachian Cohorts. There is no difference in the distribution of age and gender between the two cohorts. Of note, there is a significant difference in the distribution of race and ethnicity between the cohorts (Chi Square p < 0.001). Appalachian cohort is predominantly Non-Hispanic White.


Disclosures:
William Oelsner indicated no relevant financial relationships.
Aparna Shreenath indicated no relevant financial relationships.
Maaz Sohail indicated no relevant financial relationships.
Steven Kessler indicated no relevant financial relationships.
George Philips indicated no relevant financial relationships.
Jensen Hyde indicated no relevant financial relationships.


William K. Oelsner, MD, Aparna P. Shreenath, MD, PhD, Maaz Sohail, MD, Steven Kessler, DO, George Philips, MD, Jensen Hyde, MD, MPH. P2366 - An Emerging Health Disparity: Early Onset Colorectal Cancer in Appalachia, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.