Several decades ago, the mortality rate and incidents of breast cancer among women of low socioeconomic status (SES) were low. However, the current trends show that although breast cancer incidence remains low among low SES women, their mortality rate is steadily skyrocketing compared to women of high socioeconomic status. The increased mortality rate is attributed to disparities in breast cancer treatment and breast-conserving surgery, which are offered based on the patient’s socioeconomic status. Few studies have explained the disparities experienced by cancer patients in America, primarily lower socioeconomic status groups. Therefore, this study aimed at identifying SES disparities in receiving more effective, newer, and less invasive breast cancer treatments. The hypothesis was that near-poor and poor patients had low probability of receiving adjuvant therapies and the recommended initial breast cancer treatments than high SES women.
Methods
Data Sources and Study Population
The data used in the research was obtained from the Surveillance, Epidemiology and End Results (SEER)-Medicare database (Dreyer et al., 2018). The database contained reliable clinical data on the extent of breast cancer at presentation and the cause of death. The claim and the linked Medical enrollment files provide the socioeconomic, demographic, and patient’s cancer treatment information. Samples used in the study included older women aged between 65 and 90 years old infected with invasive, unilateral stage I–III breast cancer (Dreyer et al., 2018). The study subject diagnosis of breast cancer had to range between 2005 and 2010. The sample had only Fee-for-Service Medicare for at least one year before the breast cancer diagnosis date to enable them to measure comorbidities.
Outcome measures
The primary result of the research was the receiving of particular breast cancer treatments. Several types of auxiliary surgery were evaluated to check whether they were carried out. Receipt of chemotherapy, radiation therapy, and receiving of effective newer adjuvant endocrine therapy was assessed according to the 2005 ASCO requirements (Dreyer et al., 2018). An aromatase inhibitor was included per the ASCO recommendations. Choosing the suitable ASCO (2005) endocrine therapy regimen relied on the women’s tamoxifen usage in the first four years after the first endocrine therapy claim (Dreyer et al., 2018). Women with one claim for the AI in the said period were chosen and used as a reference group for the study.
Socioeconomic Status
Geographic identifiers and personal enrollment data were used to construct four indicators of beneficiaries’ SES: high, middle, near-poor, and poor socioeconomic status. The indicators were mutually exclusive. The groups were created based on the median household income (HHI), the proportion below the poverty line (POVT), and per capita income (PCI) (Dreyer et al., 2018). A patient was categorized as high if they were not enrolled in either state buy-in program or state of residence’s Medicaid and are in the highest quarter of HHI and PCI and lowest quarter of POVT; near-poor if they were enrolled in the state buy-in program or state of residence’s Medicaid but are in the lowest quarter of HHI and PCI and upper quarter of POVT; poor if they were enrolled in the state buy-in program or state of residence’s Medicaid, despite Census tract of home (Dreyer et al., 2018). The middle indicator was for the women who were neither enrolled in the state buy-in program or state of residence’s Medicaid nor resided in a Census tract ranking in the lowest or highest quarter of poverty. However, the category was excluded from the study analysis due to its heterogeneity.
Several covariates were also considered when selecting the study subjects. They were categorized according to their ethnicity or races as Asian, White non-Hispanic, Hispanic, Black non-Hispanic, or other ethnicities/races (Dreyer et al., 2018). Marital status was either single or married. The patient’s number of comorbidities and age at diagnosis of first breast cancer were also necessary. Other covariates were SEER site, diagnosis year, and urban status of the home county based on SEER classification, which was either the rural, urban, metropolitan area, or large metropolitan area (Dreyer et al., 2018). Clinical variables include the patient’s cancer stage, progesterone receptor, estrogen receptor, hormone receptor, and node examination status, which had to be negative, positive, or no examination taken.
Analysis
The summary statistics used means and proportions to describe the baseline demographics. Different socioeconomic status categories of breast cancer women were compared using Chi-square tests as per the clinical and demographic characteristics. The association between the socioeconomic status and receiving adjuvant chemotherapy, axillary surgery, ALND or SLNB, neoadjuvant chemotherapy, post-BCS radiation, and AI versus tamoxifen (type of endocrine therapy) was determined using the logistic regression models (Dreyer et al., 2018). However, hormone therapy studies were limited to patients with the hormone-positive condition, post-BCS radiation studies to patients under breast-conserving surgery, and adjuvant chemotherapy studies to patients with stage III or stage II conditions as per the clinical indications.
Most of the patients who received the axillary surgery were evaluated to test the chances of having ALND only, ALND and SLNB, or SLNB only (Dreyer et al., 2018). The evaluation was carried out using multinomial logistic regression. Besides the covariates mentioned above, node examination was controlled to generate adjuvant chemotherapy and neoadjuvant chemotherapy outcomes, which were significant to prevent treatment based on the condition extent. Additional control variables such as hormone receptors were included when evaluating patients’ chances of having adjuvant chemotherapy, radiation, and neoadjuvant chemotherapy. The entire study analysis was executed using STATA 12 and a 95% confidence interval. Also, Odds ratios were calculated.
Results
Out of the 11,368 women involved in the study, 48% were high, 19% near-poor, and 33% were of poor SES (Dreyer et al., 2018). As evident in the samples, patients were old and white, showing the Medicare beneficiaries’ racial distribution and the skyrocketing breast cancer cases among old white women. Most of the study subjects were unmarried and lived in metropolitan areas. Almost three out of five patients had hormone receptor-positive conditions, and almost three-quarter had stage I cancer. Compared to the high and near-poor SES, poor SES had low chances of having node examination (Dreyer et al., 2018). High socioeconomic status patients had high chances of having zero comorbidities, while poor SES patients had a high probability of having more than one comorbidity. Most study subjects received axillary surgery, and SLNB-ALND conversions were the most performed auxiliary procedures. High SES patients had high odds of receiving the initial surgical treatments than the poor women (Dreyer et al., 2018). However, no difference was spotted in using an AI or receiving neoadjuvant chemotherapy between high and poor SES patients. Near-poor and poor patients had low chances of receiving radiation after BCS than high SES women.
Discussion
The study found a reasonable relationship between receiving adjuvant and initial surgical treatments and SES. Poor SES patients received less initial surgical and adjuvant therapies than high SES patients (Dreyer et al., 2018). Among all the categories, poor SES patients had a high chance of receiving less studied treatments than high and near-poor SES categories. They are also less likely to receive SLNB attempts compared to other categories. However, there are no reasonable differences in receiving neoadjuvant therapy among the three groups because of its low prevalence during the study period (Dreyer et al., 2018).
The study showed that AIs availed a reliable control of breast cancer than the use of tamoxifen alone. The study’s findings stated that the poor women group was more disadvantaged due to their poor-income subsidies for the breast cancer treatment in question. Therefore, the study illustrated that SES disparities were not limited to comparing the extremes but existed between lower SES groups. Regarding adjuvant therapy, the study showed that poor SES women had low chances of receiving adjuvant chemotherapy and post-BCS radiation than high SES women (Dreyer et al., 2018). Most of these treatments they failed to receive are significant for biopsy and guiding quality adjuvant treatment breast cancer patients. Therefore, lack of treatments due to disparity inspired the increased mortality rate among poor SES women. These findings matched Reeder-Hayes et al. (2011) and Chen et al. (2018) reports about disparities in breast cancer treatment. Since the disparity issue remains dominant, this study aims at eliminating SES disparities among a more significant portion of breast cancer people. SES disparities are rooted in ethnicity and race and have spread their effects on healthcare. Adopting relent policy interventions will help in reducing inequalities.
In summary, the study findings showed that socioeconomic status disparities in breast cancer treatment are both substantial and persuasive. The differences continued to exist even after controlling the extent of disease and patients’ geographic area of residence. Therefore, significant disparities-generating gaps are needed to access effective follow-up or initial therapy breast cancer treatment among poor SES women
References
Chen, A. Y., Halpern, M. T., Schrag, N. M., Stewart, A., Leitch, M., & Ward, E. (2008). Disparities and trends in sentinel lymph node biopsy among early-stage breast cancer patients (1998–2005). Journal of the National Cancer Institute, 100(7), 462-474.
Dreyer, M. S., Nattinger, A. B., McGinley, E. L., & Pezzin, L. E. (2018). Socioeconomic status and breast cancer treatment. Breast cancer research and treatment, 167(1), 1-8.
Reeder-Hayes, K. E., Bainbridge, J., Meyer, A. M., Amos, K. D., Weiner, B. J., Godley, P. A., & Carpenter, W. R. (2011). Race and age disparities in receiving sentinel lymph node biopsy for early-stage breast cancer. Breast cancer research and treatment, 128(3), 863-871.
write