Income and Health-Related Quality of Life in Colorectal cancer survivors

From the Newcomb Group, Division of Public Health Sciences

In the United States, two-thirds of patients with CRC (colorectal cancer) live at least five years after diagnosis.  Early detection and effective treatments account for the increased survival rates among CRC survivors.  Yet survivors with a favorable prognosis may endure poor qualities of health because of the physical, psychosocial, and financial strain of a CRC diagnosis, especially if there is a reappearance of CRC.  As detection and treatment increase the survival rate of CRC patients, health-related quality of life (HRQoL) should be thoroughly understood to aid in the development of interventions that aim to increase survivorship and survival. Across the globe, CRC survivors report poorer overall HRQoL and well-being in comparison to general populations. Previous literature suggests that several factors influence HRQoL, including socioeconomic status (SES) characteristics such as income. Past studies report that CRC survivors with low SES have differential access to medical care and curative treatment. Also, CRC survivors with high SES are able to utilize their network of resources, including social support, and access better health care services.  However, no previous studies have examined whether the association differs by residential neighborhood SES (nSES).  A significant association would imply that living in areas with lower nSES can decrease the ability to translate income-related resources to behaviors and opportunities. The Newcomb Group, from the Division of Public Health Sciences, cross-sectionally assessed the relationship of current annual household income with self-reported HRQoL in recently diagnosed CRC patients, exploring both overall and nSES-stratified associations.   The purpose of this study is to enhance future investigator’s ability to acknowledge the influence of multilevel SES to improve HRQoL in CRC survivors. The paper is published in Cancer Epidemiology, Biomarkers, and Prevention.

The study population included CRC survivors, diagnosed from 2016 and 2018, in the Puget Sound Colorectal Cancer Cohort (PSCCC). The PSCCC is an ancillary study of the Seattle Colon Cancer Family Registry (SCCFR) cohort study.  The study’s population consisted of 1,355 CRC survivors.  Individual-level socioeconomic factors which includes household income and educational attainment were collected from surveys. Annual income was categorized as follows: <$30K, $30-69K, ≥$70K, and “unknown/prefer not to answer”.  Neighborhood SES was objectively measured using American Community Survey (ACS) five year estimates (2014-2018); six data elements were summarized – median household income, median housing unit value, percentage of households earning income from investments, percentage of persons aged ≥ 25 years who have completed high school, percentage of persons aged ≥ 25 years who have completed a college degree, and percentage of persons aged ≥ 16 years in a managerial or professional occupation – in each of the 2010 Census block groups.  The data elements were also summarized within 1-kilometer radial buffers around Census block group centroids. This was necessary to represent urban and rural participants within neighborhoods.  The outcome variable, HRQoL, was assessed using the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) database. FACT-C is specific to those receiving treatment for colorectal cancer and it includes five subscales of wellbeing: physical, social/family, emotional, functional, and CRC-specific. 

The Newcomb Group utilized generalized estimating equation (GEE) models with Gaussian distributions and clustered on participating survivor’s residential neighborhood.  After adjusting for covariates in the model, lower household income was associated with lower HRQoL in the overall study population.  CRC patients in the lowest household income group (<30K) compared with the highest household income group (≥70K) reported a difference in mean HRQoL score with a lower well-being across all subscales. These associations were slightly stronger in magnitude for survivors living in lower SES neighborhoods. However, there was little evidence in these analyses of statistically significant interactions between household income and residential nSES in their influence on HRQoL. The first author, Dr. Jamaica Robinson, elaborated on the results, “One question we found ourselves returning too was whether our findings would be the same in other geographic regions and in other cancer survivor populations. Nearly half of the survivors participating in our study reported into the highest income category listed on the survey ($≥70K); as it happens, $70K was also the annual median household income for the Seattle-Puget Sound region during the years of our study (2016-2018). It may be meaningful to look at the relationships between individual income, neighborhood wealth, and quality of life after a cancer diagnosis in more income-diverse metropolitan areas.”

Graphical Representation of View of Seattle
View of Seattle Image from Dr. Jamaica Robinson

The Newcomb Group observed similar associations between lower household income and lower HRQoL to those observed in prior survivorship studies in the US.  The findings could indicate that lower income CRC survivors living in disadvantaged neighborhoods may not have sufficient cancer health-related resources within the area.  This study also concludes that the association of income with survivorship outcome (HRQoL) can vary by nSES. Dr.  Robinson, stated, “Lower income survivors living in lower socioeconomic status neighborhoods had modestly worse quality of life relative to lower income survivors living in neighborhoods with greater socioeconomic status. This finding is important since it highlights that quality of life after a colorectal cancer diagnosis is likely a function of both individual and neighborhoods characteristics.” Income is a critical determinant of survivor well-being and these results are consistent with previous findings from both population-and clinic-based studies.

Dr. Robinson concluded, “Based on our findings, we hypothesized that neighborhoods with lower socioeconomic status may not have crucial health and supportive care resources for cancer survivors accessible or even available at all. One important direction that could be built off this research would be to map the availability, accessibility, and capacity of needed survivorship resources at the neighborhood level. Because historical and contemporary structural racism likely impacts which resources are present in which neighborhoods, future research would also likely need to further specify whether cancer care services are equitably available and accessible and also interrogate what systems-level changes needed to be made to address racial disparities in CRC survivorship.” This was the first survivorship study to explore whether relationships between income and HRQoL in colorectal cancer survivors vary with nSES.

This research was supported by the National Cancer Institute and the National Institute of Environmental Health Sciences.

Fred Hutch/UW Cancer Consortium members Amanda I. Phipps, Wendy E. Barrington, and Polly A. Newcomb contributed to this work.

Robinson JRM, Phipps AI, Barrington WE, Hurvitz PM, Sheppard L, Malen RC, Newcomb PA. Associations of household income with health-related quality of life following a colorectal cancer diagnosis varies with neighborhood socioeconomic status. Cancer Epidemiology and Prevention Biomarkers. 2021 Jan 1.