EP1065 - Higher Income Associated with Delayed Diagnosis of Early Onset Colorectal Cancer

Purpose/Background: Early onset colorectal cancer (EOCRC) is increasing in incidence over time, with incidence rates increasing 2% per year. The reasons for this are likely multifactorial. Unfortunately, EOCRC is often identified in later stages because these young patients do not typically meet criteria for colonoscopic screening. This study was designed to evaluate risk factors for specific subsets of EOCRC including characteristics associated with higher staged cancer, lymph node metastasis, and those with microsatellite instability.

Methods/Interventions: A retrospective cohort study analyzed EOCRC cases and non-cases from 2021-2023 at a tertiary care center who underwent colonoscopy for any reason during this time. Non-cases were < 50 years old with normal colonoscopy results. Pathology reports, demographics, symptoms, and family history were collected. Logistic regression with LASSO selection assessed the multivariate relationship between colorectal cancer features. Subset analyses of cancer cases were performed based on staging, nodal metastases, and microsatellite stability.

Results/Outcomes: A total of 453 patients were identified to meet inclusion criteria (44% cancer cases, 56% control cases). When the data were subset among just CRC cases - increased household income was associated with higher staged cancers (stage 0-2=$43,600 vs stage 3-4=$51,400; p=0.023), the presence of lymph node metastases (Lymph node positive=$45,400/yr vs lymph node negative=$50,700/yr; p=0.049), and with microsatellite stable tumor biology (MSS=$41,100/yr vs MIS=48,100/yr; p=0.032). Microsatellite instability tended to occur in younger patients, even among an early onset cancer population (mean age 39 years old vs 44 years old; p=0.010).

Conclusion/Discussion: When our data was subset among cancer cases, the only factor that was identified to be statistically significantly associated with microsatellite stability, higher stage at diagnosis, and lymph node metastases was higher household income. It is not entirely clear why this is the case, but marginally higher income may be related to paradoxical decreased access to care. For example, the yearly household income required to qualify for Medicaid in the state of Kentucky during this time period for a family of four with two children was between $34,000 and $47,000. Those falling above these income requirements may have had intermittent coverage or absent coverage to seek care, leading to later stage diagnosis and an association with lymph node metastases. In addition, lower mean age and age distribution was noted in microsatellite unstable cancers which is concordant with other studies due to presumed family history.

Table 1: Factors associated with microsatellite stability and lymph node metastases in early onset colorectal cancer
Table 2: Factors associated with final stage of early onset colorectal cancer