Utilization of Lymph Node Dissection, Race/Ethnicity, and Breast Cancer Outcomes | Page 2
Published Online: October 23, 2013
Zhannat Z. Nurgalieva, MD, PhD; Luisa Franzini, PhD; Robert O. Morgan, PhD; Sally W. Vernon, PhD; and Xianglin L. Du, MD, PhD
Patients of African American descent or of Hispanic origin had reduced OS after adjusting for selected covariates. Older women or those with macrometastases, highgrade tumors, larger tumors, negative estrogen receptor status, or more positive lymph nodes found during surgery had reduced OS. Adjusting for nodal surgery did not reduce racial/ethnic disparities in OS. Patients of Hispanic origin who were older or who had high-grade tumors, larger tumors, or negative estrogen receptor or progesterone receptor status; who underwent complete ALND after SLNB; or who had more positive lymph nodes found during surgery had reduced DSS. Disease-specific survival was decreased in patients with macrometastasis (not statistically significant). Adjusting for nodal surgery did not reduce racial/ethnic disparities in DSS.
Yi and colleagues4 recently examined differences in survival for patients with nodal disease undergoing SLNB alone versus SLNB with complete ALND. Similar to their results, we found no significant differences in utilization of SLNB alone or SLNB with a complete ALND between Caucasian and African American older BC patients in a cohort restricted to those with micrometastasis and macrometastasis in sentinel lymph nodes. In our study, this observation also held true for Hispanics and Asians/Pacific Islanders. Our study is unique in that it is one of the first reports of health outcomes in older BC patients with nodal disease for Hispanics, Asians, and Pacific Islanders. Previously mentioned studies did observe racial/ethnic disparities in utilization or quality of nodal surgery.1,5-8 This difference probably reflects the fact that their purpose was not to address BC survival with receipt of nodal surgery; therefore, they did not restrict their study population to only those with nodal disease. Similar to the findings reported by Bilimoria and colleagues3 and Yi and colleagues,4 our study suggests that patients are more likely to receive SLNB alone if they undergo breast-conservation therapy, are older, and have smaller primary tumors.
We observed that adjusting for receipt of nodal surgery did not reduce racial/ethnic disparities. Being of African American descent was associated with reduced OS, while being of Hispanic origin was associated with reduced DSS and OS compared with being Caucasian. This finding is consistent with the findings of Ooi and colleagues,9 who used SEER data to study women diagnosed with invasive breast carcinoma between 2000 and 2006. Ooi and colleagues showed elevated risk of BC-specific mortality among Hispanic whites and blacks that persisted after adjustments for important outcome predictors.
Yi and colleagues4 found a statistically significant hazard of mortality (HR = 1.3; 95% CI, 1.1-1.6) for women aged 18-99 years undergoing a complete ALND compared with those undergoing SLNB only. They attributed this difference to more advanced disease in patients undergoing SLNB with complete ALND. In our study of Medicare beneficiaries 65 years and older, we obtained similar results, with the hazard of BC-specific mortality of a slightly higher magnitude (HR = 1.6; 95% CI, 1.1-2.5).
This study has several limitations, as previously described.4,22 Medicare beneficiaries in the fee-for-service program represent a self-selected population. Our data set does not include beneficiaries enrolled in health maintenance organizations. Hispanic women are more likely to be in Medicare health maintenance organizations (because of the residence area),23 which might lead to selection bias. Both Hispanic and African American women are less likely than white women to have supplemental coverage, and they are more likely to have Medicaid.23 Comparisons of the accuracy of Medicare’s race codes with self-report (using the Medicare Current Beneficiary Survey data) suggested that the primary error is in mistakenly identifying some Asians, Native Americans, and Hispanics as white.24 The impact of the misclassification has not been examined to date. Because patient comorbidity is identified from diagnoses coded on claim forms, BC survivors’ greater interaction with care providers may explain their higher measured comorbidity. Income, supplemental insurance, and availability of providers all significantly affect access to care and are not included in our models except as grossly approximated by census tract socioeconomic status quartile and urban-rural status.
In summary, this study examined the effect of nodal surgery, an initial part of longitudinal healthcare for older BC patients, on racial disparities in survival. Overall survival is comparable for those who undergo SLNB alone and those who undergo SLNB with complete ALND among women with BC. African American women have lower OS and women of Hispanic origin have a lower DSS and OS compared with their white counterparts. These disparities in survival are not explained by differences in utilization of ALND among women with micrometastasis and macrometastasis in sentinel lymph nodes.
Author Affiliations: From the Divisions of Epidemiology, Human Genetics & Environmental Sciences (ZZN, XLD), Management, Policy and Community Health (LF, ROM), and Health Promotion and Behavioral Sciences (SWV), School of Public Health, University of Texas Health Science Center, Houston, TX.
Funding Source: This work was supported by grant KG090010 (A Transdisciplinary Training Program for Public Health Researchers and Practitioners Wanting to Impact Breast Cancer Disparities) from the Susan G. Komen Breast Cancer Foundation; and in part by grant R01-HS018956 from the Agency for Healthcare Research and Quality.
Author Disclosures: The authors (ZZN, LF, ROM, SWV, XLD) report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.
Authorship Information: Concept and design (ZZM, LF, ROM, XLD); acquisition of data (XLD); analysis and interpretation of data (ZZN, ROM, SWV, XLD); drafting of the manuscript (ZZN, LF, XLD); critical revision of the manuscript for important intellectual content (ZZN, LF, ROM, SWV, XLD); statistical analysis (ZZN, XLD); provision of study materials or patients (XLD); obtaining funding (XLD); administrative, technical, or logistic support (XLD); and supervision (LF, XLD).
Address correspondence to: Zhannat Z. Nurgalieva, MD, PhD, Division of Epidemiology, Human Genetics, and Environmental Sciences, University of Texas Health Science Center at Houston, 1200 Herman Pressler Dr, RASE631, Houston, TX 77030. E-mail: firstname.lastname@example.org.
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