BACKGROUND: Colorectal cancer (CRC) accounts for about 10% of all cancers in the VA. Three-year survival is associated with both age at diagnosis and CRC stage. Yet, the minority of cases are detected at an early stage and the overall incidence of cancer in the VA patient population is forecast to rise. CRC survival and pathogenesis differ by tumor location Increases in CRC cases in individuals younger than fifty-years-of age and at more advanced stages have been reported in large, U.S. population-based cohorts (Meester et al., 2019). Here, we present a preliminary investigation of these trends amongst CRC patients in the VA.
METHODS: Briefly, a cohort of veteran patients (n = 40,951) was identified from 2000 – 2017 using the VA Central Cancer Registry (VACCR). We required all included patients to have a histologically-confirmed case of CRC as consistent with previous studies (Zullig et al., 2016) and only one registry entry. We constructed Kaplan- Meier curves and created a Cox-Proportional Hazards model to examine survival. Additional filtering by age at the date of diagnosis was used to identify patients between ages 40 and 49 and tumor location as abstracted in the VACCR. Regression analysis was used to examine trends in stage at diagnosis and in those between aged 40 and 49.
RESULTS: Our findings indicate that proximal (rightsided) colon cancer is associated with poorer survival than distal (left-sided), consistent with previous findings. During this time period, 3% of the cohort or 1,249 cases were diagnosed amongst individuals of ages 40 – 49. Regression analysis indicated differences in trends amongst VHA patients younger than fifty years of age and in stage at diagnosis. Though, the time period of this study was shorter than those previously published.
CONCLUSION: Further work is underway to identify the sources of these differences in survivorship in VHA patients, including the analysis of therapeutic regimens. This work was performed under R&D and IRB protocols reviewed approved by the VA Boston Healthcare System.
