Household Income May Impact Recurrence Score and Survival in ER+ Breast Cancer

Sung Jun Ma, MD

Low-income households of patients with estrogen receptor (ER)-positive breast cancer show association with higher 21-gene recurrence scores and significantly worse survival outcomes compared with high income households.¹

Recurrences scores, which are scores based on gene signature that indicate a patients’ risk for distant metastasis, were below 26, but not 26 or higher in the low-income population. The results warrant more studies into the association between the relativity of socioeconomics and health and tumor biology among patients with breast cancer.

Extensive research has investigated the roles of socioeconomic inequities and breast cancer disparities in patient outcomes, but none have tackled the correlation between socioeconomic determinants of health and intrinsic tumor biology, even though the 21-gene recurrence score has been incorporated into routine clinical care in the United States.

Moreover, prior research shows an association between socioeconomic status and low recurrence scores in patients with ER-positive breast cancer, triple-negative breast cancer (TNBC) in particular.

“Socioeconomic status is associated with intrinsic tumor biology and how aggressively cancer behaves, not just access to care and adherence to treatments,” Sung Jun Ma, MD, a radiation oncology resident, Department of Radiation Medicine, Roswell Park Comprehensive Cancer Center, told Targeted Oncology™.

The cohort study was designed by Roswell Park Comprehensive Cancer Center and its design was reviewed by an institutional review board. Assessing information from 119,478 women with breast cancer, the coprimary end points were recurrence score and overall survival (OS).

The study population was comprised of women with a median age of 60 years (IQR, 52-67). Of the 119478 patients, 4737 (4.0%) were Asian/Pacific Islander, 9226 (7.7%) were Black, 7245 (6.1%) were Hispanic, and 98270 (82.2%) were non-Hispanic White. In terms of income, 82198 patients (68.8%) were considered high-income, and 37280 (31.2%) were classified as low-income. Baseline characteristics were well-balanced between the 2 groups.

Compared with the high-income group, patients with low income had a higher recurrence score (adjusted odds ratio [aOR], 1.11; 95% CI, 1.06-1.16). The interaction term analysis showed a statistically significant interaction between income levels and recurrence score (interaction P < .001).

In a subgroup analysis looking at OS, there were no significant OS differences between income levels. However, low-income patients did show slightly higher recurrence score than high-income patients.

A sensitivity analysis conducted with non-Hispanic White women with high education and private medical insurance, and it showed that having low-income individuals had higher recurrence score compared with high-income individuals (aOR, 1.16; 95% CI, 1.05-1.28; P = .003).

According to the investigators, this study using a nationwide oncology database is the largest study to signal that low household income correlates with higher recurrence scores and worse survival outcomes.

The study was limited by retrospective nature as well as clinical characteristics like patients’ performance scores, tumor recurrence, breast cancer-specific survival, systemic therapy agents, and adherence to screening and treatments.

“More studies are needed to investigate the mechanism behind the association between socioeconomic determinants of health and tumor biology,” said Ma.

_REFERENCE:

_{Ma SJ, Gill J, Waldman O, et al. Association of neighborhood-level household income with 21-gene recurrence score and survival among patients with estrogen receptor–positive breast cancer. JAMA Netw Open. 2023;6(2):e230179. doi:10.1001/jamanetworkopen.2023.0179}