Although we found no DCIS treatment disparities by race/ethnicity, use of adjuvant radiation therapy was less among older women and among residents of poorer neighborhoods.
Published Online: May 11, 2010
Reina Haque, PhD; Ninah S. Achacoso, MS; Suzanne W. Fletcher, MD, MSc; Larissa Nekhlyudov, MD, MPH; Laura C. Collins, MBBS; Stuart J. Schnitt, MD; Charles P. Quesenberry Jr, PhD; and Laurel A. Habel, PhD
Objective: To examine whether use of adjuvant therapy varies by race/ethnicity among patients with ductal carcinoma in situ (DCIS) at 3 integrated health plan delivery sites based in California and Massachusetts.
Study Design: Cross-sectional study nested within a cohort of women diagnosed as having DCIS between 1990 and 2001.
Methods: We reviewed medical records of 3000 non-Hispanic white (69%), black (10%), Hispanic (9%), and Asian or Pacific Islander (12%) women diagnosed as having DCIS between 1990 and 2001 and treated with breast-conserving therapy. X2 Test and multinomial logistic regression analysis were used to examine the association between race/ethnicity and use of adjuvant treatments after controlling for patient and clinical variables, including certain pathologic factors.
Results: We found no significant differences in DCIS adjuvant treatment among racial/ethnic groups in bivariate or multinomial analyses after adjusting for demographic characteristics, comorbidity, and clinical factors. Minority women were as likely to undergo adjuvant radiation therapy as non-Hispanic white women. However, women 70 years or older (odds ratio, 0.40; 95% confidence interval, 0.31-0.51) and women who lived in areas with low geocoded median family income (odds ratio, 0.65; 95% confidence interval, 0.48-0.89) were less likely to receive adjuvant radiation therapy. Tumor size and comedo histologic growth pattern were associated with increased likelihood of receiving radiation therapy.
Conclusion: Use of adjuvant therapy by minority women in these managed care plans is similar to that by non-Hispanic white women, although use was less among older women and among women who lived in poorer neighborhoods.
(Am J Manag Care. 2010;16(5):351-360)
The lack of differences in the treatment of ductal carcinoma in situ by race/ethnicity observed in these integrated healthcare delivery systems may be due to coordinated clinical guidelines and multidimensional approaches to reduce barriers in care by educating physician leaders, nurse practitioners, case managers, and disease management program managers in these organizations.
However, older women (>70 years) and women who lived in census tracts with low median family incomes were less likely to receive adjuvant radiation therapy.
Such groups of women may have different functionality, comorbidity burden, and treatment preferences, all of which need to be considered in the treatment decision-making process.
The diagnosis of ductal carcinoma in situ (DCIS) has increased markedly because of enhanced screening mammography efforts and constitutes more than 20% of newly diagnosed breast cancer cases in the United States.1 Despite improvements in detection, determining the most appropriate treatment strategy remains a challenge owing to the heterogeneity of DCIS lesions.2-4 While racial/ ethnic differences have been reported for the detection, diagnosis, evaluation, and treatment of invasive breast cancer, data are limited on whether there are similar disparities in the treatment of DCIS.5-7 Recent studies8-10 of women with invasive disease have found that racial/ ethnic minority women undergo breast-conserving surgery (BCS) more frequently than white women; however, black women are at twice the risk of white women for failing to receive postsurgery chemotherapy and hormonal therapy. This racial/ethnic disparity in the receipt of adjuvant therapy for invasive disease has been reported in many settings.5,8,10-17
In contrast, less information on treatment disparity exists for DCIS than for invasive disease.6,18 Because DCIS can progress to invasive disease, it is critical to determine whether modifiable and nonmodifiable factors are associated with receipt of therapy. While controversy exists regarding optimal treatment for DCIS, research indicates that women treated with BCS and subsequent radiation therapy have significantly reduced recurrence versus women treated with surgery alone.6,19 The risk of recurrence can be further reduced by combining radiation therapy with adjuvant tamoxifen citrate treatment.20,21 Breast-conserving surgery with adjuvant tamoxifen treatment alone is generally not a recommended option.In addition, neither cytotoxic chemotherapy nor any of the newer biologic agents are recommended for DCIS.
Previous studies8,18,22-28 that have examined breast cancer treatment differences were based on claims data from fee-for-service settings; however, these sources offer a limited understanding of utilization. Tumor registries reliably capture information on surgery and race/ethnicity but less reliably capture adjuvant radiation therapy or hormonal treatment data.8 Such databases generally also lack data on socioeconomic status, which may contribute to treatment differences.8 Medical record review is resource intensive but enables more comprehensive insight into treatments used. The objective of this study was to use information abstracted from medical records to examine whether use of adjuvant therapy varied by race/ethnicity among a diverse cohort of 3000 women diagnosed as having DCIS between 1990 and 2001 and treated with BCS in 3 geographically diverse integrated healthcare delivery systems. A key advantage of this study is the additional information we captured on pathologic features and socioeconomic factors that vary by race/ethnicity and may influence treatment decisions.
Design and Setting
This study was conducted at 3 sites participating in the Cancer Research Network, a consortium of research organizations affiliated with nonprofit integrated healthcare delivery systems and the National Cancer Institute. Study participantsincluded women enrolled at Kaiser Permanente Northern California, Kaiser Permanente Southern California, and Harvard Pilgrim Health Care. The sites care for more than 6 million members in California and Massachusetts. We examined patient and healthcare factors associated with utilization of adjuvant cancer treatment (radiation therapy and hormonal therapy). This study was part of a retrospective cohort study of women diagnosed as having DCIS between 1990 and 2001. The study was approved by the institutional review boards at all 3 study sites.
Women with DCIS were identified through the Kaiser Permanente health plans’ electronic cancer registries in California. These health plans report cancer cases in specific geographic regions to the SEER (Surveillance, Epidemiology and End Results) program. At Harvard Pilgrim Health Care, claims and electronic outpatient medical records were used to identify women with DCIS.
The cohort included women from Kaiser Permanente Northern California, Kaiser Permanente Southern California, and Harvard Pilgrim Health Care who were aged 20 to
84 years at diagnosis of DCIS, were diagnosed between 1990 and 2001, had unilateral disease, were treated with BCS, had no history of DCIS or invasive cancer (breast or other site), and remained enrolled within the health plans for at least 6 months after diagnosis.
Of 3668 patients identified as potentially eligible by our cancer registries or electronic medical records, 602 were deemed ineligible for 1 or more of the following reasons based on medical record review: unavailability of medical records (n = 82), miscoding of DCIS in the cancer registry (n = 63), prior breast or other cancer (n = 216), bilateral breast cancer at diagnosis (n = 29), mastectomy for the index DCIS (n = 96), age 85 years or older at diagnosis (n = 15), or lack of follow-up in the health plan for 6 consecutive months (n = 101). Of 3066 remaining patients, 29 women had unknown treatment and 37 women had missing race/ethnicity, leaving 3000 patients for this study.
We used standardized medical record abstraction forms to capture information on treatment (surgery, radiation therapy, chemotherapy, and hormonal therapy), history of breast cancer among first-degree relatives, year of diagnosis, and height, weight, and age at index DCIS diagnosis. Family history of breast cancer was history of the disease in a first-degree blood relative (including mother, sisters, half sisters, or daughters) of the study patient. We recorded information on family history if it appeared in the medical record within 6 months of the study patient’s DCIS diagnosis.
We also collected information on the presence of diabetes mellitus around the time of DCIS diagnosis as a surrogate measure of comorbidity because findings from studies29,30 suggest that patients with diabetes are treated less aggressively for cancer. The analysis presented herein examines the initial course of treatment documented in the medical records in the 6 months after DCIS diagnosis. Because detection methods can vary by race/ethnicity and influence treatment decisions, we abstracted information as to whether the breast lesion was identified through palpation or screening mammography. Because prevalence of pathologic features may vary by race/ethnicity and may influence treatment decisions, we conducted a subset analysis involving 1 study site (n = 986). At this study site, we abstracted key features from the pathology reports such as surgical margins, tumor size, comedo histologic growth pattern, necrosis, and nuclear grade. Because the health plan tumor registries in California did not uniformly capture pathologic variables during the study period, we assessed these factors based on review of the original pathology
report and specimens by a single study pathologist rather than through the SEER program. In this way, the pathologic variables were measured in a standard manner for all patients at this study site whether or not the patients lived in a geographic area covered by the SEER program during the study period (1990-2001).
Information on race/ethnicity was captured from the medical records or the electronic SEER-affiliated cancer registries (in California). The SEER data are based on medical records and administrative information. We grouped race/ethnicity as non-Hispanic white, black, Hispanic, or Asian or Pacific Islander. Because the health plans do not uniformly collect members’ income or educational attainment, information on these factors was obtained from geocoding files based on California’s 1990 census (which was closest to the DCIS diagnosis dates). In this approach, the women in the cohort were classified according to the socioeconomic characteristics of their census tract at the time of diagnosis.31,32 Geocoded educational attainment and median family income were based on the distribution of the women in our sample (the cohort’s census tract). Geocoded educational attainment was divided into 2 groups (high vs low). High geocoded educational attainment means that the percentage of women in the sample with at least some college education is greater than the percentage of women in the cohort with at most a high school diploma. Geocoded median family income was divided into quartiles. Analyses considering median family income and educational attainment were restricted to patients in California (93% of
the study cohort). Similar information was not feasible to ascertain for patients in Massachusetts.
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