Individual‐ and neighborhood‐level socioeconomic status and risk of aggressive breast cancer subtypes in a pooled cohort of women from Kaiser Permanente Northern California

Abstract

BACKGROUND: Low socioeconomic status (SES) has been associated with a higher risk of aggressive breast cancer (BC) subtypes, but few studies have examined the independent effects of both neighborhood-level socioeconomic status (nSES) and individual-level SES measures. METHODS: This study included 5547 women from the Pathways and Life After Cancer Epidemiology cohorts who were diagnosed with invasive BC. Generalized estimating equation models were used to examine associations of nSES (a composite score based on income, poverty, education, occupation, employment, rent, and house value) and individual-level SES (income and education) with BC subtypes: luminal B (LumB), Her2-enriched (Her2-e), and triple-negative breast cancer (TNBC) relative to luminal A (LumA). Models controlled for age, race, nativity, stage, days from diagnosis to survey, and study cohort and simultaneously for nSES and individuallevel SES. RESULTS: In fully adjusted models, low nSES was significantly associated with the LumB (odds ratio for quartile 1 vs quartile 4 [OR Q1vQ4 ], 1.31; 95% confidence interval [CI], 1.11-1.54; P for trend = .005) and TNBC subtypes (OR Q1vQ4 , 1.32; 95% CI, 1.02-1.71; P for trend = .037) relative to LumA. Conversely, individual education was significantly associated with only the Her2-e subtype (odds ratio for high school degree or less vs postgraduate, 1.68; 95% CI, 1.03-2.75; P for trend = .030) relative to LumA. Individual income was not significantly associated with any BC subtype. CONCLUSIONS: nSES and individual-level SES are independently associated with different BC subtypes; specifically, low nSES and individual-level education are independent predictors of more aggressive BC subtypes relative to LumA. Cancer 2021;127:4602-4612.

Occupational Factors and Socioeconomic Differences in Breast Cancer Risk and Stage at Diagnosis in Swiss Working Women

“…Mechanisms purported to explain the association of SES with BC aetiology, particularly BC subtypes, include reproductive and environmental factors and chronic stress [ 37 , 38 ]. An increasing number of women, particularly high SES women, who entered the workforce over the last decades, have delayed childbearing, lower parity and higher use of hormonal contraceptives compared to women of lower SES [ 38 ].…”

“…Mechanisms purported to explain the association of SES with BC aetiology, particularly BC subtypes, include reproductive and environmental factors and chronic stress [ 37 , 38 ]. An increasing number of women, particularly high SES women, who entered the workforce over the last decades, have delayed childbearing, lower parity and higher use of hormonal contraceptives compared to women of lower SES [ 38 ]. The increased prevalence of these risk factors mainly among women of greater educational attainment contribute to their higher incidence, particularly of tumours with positive hormone receptors, the more common and less aggressive subtype of BC.…”

Time to Surgery in Breast Cancer—Is Faster Always Better?

“…Time to surgery might matter very little for indolent, screen-detected cancers, but time to treatment start might matter very much for fast-growing, interval cancers . These faster-growing cancers are more common in certain patient populations with an association seen between worse socioeconomic status and nonluminal A tumors . We wonder if including these socioeconomic indicators in the overall model would mitigate the association between time to surgery and survival seen in this study.…”

Association of Social Determinants and Tumor Biology With Racial Disparity in Survival From Early-Stage, Hormone-Dependent Breast Cancer

“…Contextual factors that encompass societal conditions and policy decisions, neighborhood disadvantage, and individual socioeconomic deprivation all contribute to the racial disparity in breast cancer mortality . Emerging evidence indicates that social determinants can also influence tumor biology …”

“…8,[18][19][20][21][22] Emerging evidence indicates that social determinants can also influence tumor biology. 14,15,23,24 The Oncotype DX 21-gene Breast Recurrence Score (RS) is the most commonly ordered genomic biomarker for breast cancer in the US, 25 and guidelines for systemic adjuvant therapy are based on this gene expression profile for patients with ER-positive, axillary node-negative tumors. 26 In a previously reported analysis of the the Surveillance, Epidemiology, and End Results (SEER) Oncotype Dx Database, 12 we demonstrated that ER-positive, axillary node-negative breast cancer tumors diagnosed in Black women were 30% more likely to have a high-risk RS compared with tumors from White women.…”