A neighborhood analysis of socioeconomic status conducted in the Pittsburgh area found worse metastatic breast cancer survival outcomes among patients of low socioeconomic status. The findings suggest that race is not a relevant factor in outcomes.
“This study demonstrates that metastatic breast cancer patients of low socioeconomic status have worse outcomes than those with higher socioeconomic status at our center. It also underscores the idea that race is not so much a biological construct but more a consequence of socioeconomic issues. The effect of race is likely mediated by lower socioeconomic status,” said Susrutha Puthanmadhom Narayanan, MD, who presented the results of her study earlier this month in Chicago at the annual meeting of the American Society of Clinical Oncology.
“The current study should make clinicians cognizant of the potential for biases in the management of metastatic breast cancer in terms of socioeconomic status and race. One should think of socioeconomic status as a predictor of bad outcomes, almost like a comorbidity, and think of [associations between race and outcomes], as a consequence of socioeconomic inequality,” said Dr. Puthanmadhom Narayanan, who is an internal medicine resident at University of Pittsburgh Medical Center.
She and her colleagues intend to dig deeper into the relationships. “We are interested in looking at utilization of different treatment options for metastatic breast cancer between the socioeconomic status groups. In the preliminary analysis, we saw that ER-positive metastatic breast cancer patients with lower socioeconomic status get treated with tamoxifen more often than aromatase inhibitors and newer agents. And, we have plans to study stress signaling and inflammation as mediators of bad outcomes in the low socioeconomic status population,” Dr. Puthanmadhom Narayanan said.
In fact, that tendency for lower socioeconomic status patients to receive older treatments should be a call to action for physicians. “This study should make clinicians cognizant of the potential for biases in management of metastatic breast cancer in terms of socioeconomic status and race,” she said.
The study is based on an analysis of data from the Neighborhood Atlas in which a Neighborhood Deprivation Index (NDI) score was calculated. An NDI score in the bottom tertile meant that patients were better off than patients with mid to high range NDI scores. In this study, socioeconomic status was described as “low deprivation” or “high depreviation.” Higher deprivation correlated with lower overall survival. And, there were more Black patients in the higher deprivation group (10.5%), compared with the low deprivation group (3.7%). In multivariate Cox proportional hazard model, socioeconomic status, but not race, had a significant effect on overall survival (HR for high deprivation was 1.19 [95% confidence interval; 1.04-1.37], P = 0.01).
It included 1,246 patients who were treated at the University of Pittsburgh Medical Center between 2000 and 2017. Of 1,246 patients, 414 patients considered in the bottom tertile of NDI as having low deprivation, while 832 patients in the middle or top tertiles were classified as having high deprivation.
The two socioeconomic status groups were similar in baseline characteristics, with the exception of race: 10.5% of the high deprivation group were African American, compared with 3.7% of the low deprivation group (P =.000093).
Univariate analyses showed worse survival in both Black women and women in the lower socioeconomic status group, but a multivariate analysis found only socioeconomic status was associated with overall survival (hazard ratio for lower socioeconomic status, 1.19; P = .01).
The study had several strengths, according to Rachel Freedman, MD, MPH, who served as a discussant for the abstract. “It included both de novo and recurrent metastatic breast cancer, unlike previous studies based on the Surveillance, Epidemiology, and End Results (SEER) database that only included de novo cases. It also employed a novel tool to define socioeconomic status in the form of the Neighborhood Atlas. The study “adds more evidence that socioeconomic status likely mediates much of what we see when it comes to racial disparities,” said Dr. Freedman, who is a senior physician at Dana Farber Cancer Institute.
Nevertheless, more work needs to be done. Dr. Freedman pointed out that the current study did not include information on treatment.
“We need to standardize the way that we collect social determinants of health and act upon findings, and we need to standardize patient navigation, and we need to commit as a community to diverse clinical trial populations,” Dr. Freedman said.
Dr. Narayanan has no relevant financial disclosures. Dr. Freedman is an employee and stockholder of Firefly Health.