Abstract P3-10-03: Socioeconomic disparities in needle biopsy prior to breast cancer surgery across physician referral networks

Abstract Introduction Although needle biopsy (NB) is recommended prior to breast cancer surgery, the use of NB has been shown to vary according to patient socioeconomic status (SES), operating surgeon, and geographic region. We hypothesized that surgeons who work in the same peer referral network (defined by patient sharing) might have similar practice patterns with regard to NB, and that the magnitude of SES disparities might vary across networks. We therefore examined: 1) SES disparities in the receipt of NB, 2) variation in NB across networks, and 3) whether the association between SES and NB varied across networks. Methods We used the SEER database and 5% Medicare sample to examine all patients with a new diagnosis of breast cancer from 2004 through 2006. We used Medicare claims to construct peer groups of physicians based on patient-sharing ties. Patients were assigned to peer groups based on the surgeon who performed their definitive surgery. We defined a patient as having low SES if she was in the lowest quintile of area-level income. We used hierarchical generalized linear models (HGLM) to assess the association between low SES and receipt of NB, including random effects for the surgeon, peer group, and Hospital Referral Region (HRR). We then allowed the low SES effect to vary across peer groups in order to determine whether the association between SES and NB varied across groups. Results In the full sample of 14,552 patients, 9,498 (65%) received needle biopsy. In bivariable analysis, patients in the lowest income quintile were less likely to receive NB compared to all other patients (59% vs 67%, p&amp;lt;.001). The majority of the variance (59%) in NB use was at the patient level, 22% was at the surgeon level, and 13.7% at the peer group level. The use of NB varied substantially across peer groups, with a median of 69% (interquartile range [51%, 84%]). Even after accounting for physician, peer group, and HRR variation, patients in the lowest stratum of SES were significantly less likely to have received NB compared to all other patient (OR = 0.88; p=.04). Finally, we found that the association between SES and NB varied significantly across referral networks (P&amp;lt;0.05) Conclusions Patients with low SES are significantly less likely to receive NB prior to breast cancer surgery, and moreover the magnitude of this SES-related disparity varies significantly according to which referral networks are providing care. Future policies to increase NB rates and standardize care for all breast cancer patients may consider the implications of how care for patients with low SES varies across surgical provider networks.Introduction Although needle biopsy (NB) is recommended prior to breast cancer surgery, the use of NB has been shown to vary according to patient socioeconomic status (SES), operating surgeon, and geographic region. We hypothesized that surgeons who work in the same peer referral network (defined by patient sharing) might have similar practice patterns with regard to NB, and that the magnitude of SES disparities might vary across networks. We therefore examined: 1) SES disparities in the receipt of NB, 2) variation in NB across networks, and 3) whether the association between SES and NB varied across networks. Methods We used the SEER database and 5% Medicare sample to examine all patients with a new diagnosis of breast cancer from 2004 through 2006. We used Medicare claims to construct peer groups of physicians based on patient-sharing ties. Patients were assigned to peer groups based on the surgeon who performed their definitive surgery. We defined a patient as having low SES if she was in the lowest quintile of area-level income. We used hierarchical generalized linear models (HGLM) to assess the association between low SES and receipt of NB, including random effects for the surgeon, peer group, and Hospital Referral Region (HRR). We then allowed the low SES effect to vary across peer groups in order to determine whether the association between SES and NB varied across groups. Results In the full sample of 14,552 patients, 9,498 (65%) received needle biopsy. In bivariable analysis, patients in the lowest income quintile were less likely to receive NB compared to all other patients (59% vs 67%, p&amp;lt;.001). The majority of the variance (59%) in NB use was at the patient level, 22% was at the surgeon level, and 13.7% at the peer group level. The use of NB varied substantially across peer groups, with a median of 69% (interquartile range [51%, 84%]). Even after accounting for physician, peer group, and HRR variation, patients in the lowest stratum of SES were significantly less likely to have received NB compared to all other patient (OR = 0.88; p=.04). Finally, we found that the association between SES and NB varied significantly across referral networks (P&amp;lt;0.05) Conclusions Patients with low SES are significantly less likely to receive NB prior to breast cancer surgery, and moreover the magnitude of this SES-related disparity varies significantly according to which referral networks are providing care. Future policies to increase NB rates and standardize care for all breast cancer patients may consider the implications of how care for patients with low SES varies across surgical provider networks. Citation Format: Killelea BK, Herrin J, Soulos PR, Pollack CE, Forman HP, Yu J, Xu X, Tannenbaum S, Wang S, Gross CP. Socioeconomic disparities in needle biopsy prior to breast cancer surgery across physician referral networks [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-10-03.</jats:p

Abstract P6-07-05: Regional variation in Medicare expenditures for older women with localized breast cancer

Abstract Objectives: To characterize variation in Medicare expenditures on initial breast cancer care across hospital referral regions (HRRs) and to examine the relative contribution of patient characteristics and treatment factors to such variation. Methods: This was a retrospective cohort study using the 2003-2007 Surveillance, Epidemiology and End Results (SEER)-Medicare linked database and the Medicare 5% random sample of non-cancer beneficiaries. Each woman with localized (stage I-III) breast cancer (“case”) was matched to a woman without cancer (“control”) based on HRR, age, comorbidity and Medicare expenditure in the year prior to cancer diagnosis. We defined initial phase of care as the period from two months prior to breast cancer diagnosis (for cases) or index date (for controls) through 12 months after the diagnosis or index date. For each HRR, we calculated the risk-standardized cancer-related Medicare expenditure as the difference in total expenditure between cases and controls, using hierarchical generalized linear models to control for clustering by HRR and adjust for patient characteristics (age, race, comorbidity, and tumor characteristics) and treatment factors. Treatment factors were first assessed by whether different treatments were used (surgery, radiation therapy, chemotherapy, growth factors, and imaging services), and then assessed by specific treatment modalities (breast conserving surgery, radical mastectomy, intensity modulated radiation therapy, external beam radiation therapy, brachytherapy, traditional chemotherapy, biological therapy, growth factors, and imaging). All estimates were reported in 2009 U.S. dollars. Results: There were 35,055 patients with breast cancer and an equal number of controls in our cohort. After excluding HRRs with fewer than 25 cases, there were 78 HRRs in our final analysis. Unadjusted Medicare expenditure on breast cancer-related care averaged $19,207 per patient. HRRs in the highest quintile had an average expenditure of$23,522 per patient, which was $8,032 higher than HRRs in the lowest quintile (mean expenditure =$15,490). Patient characteristics explained only 18.5% of the difference in total cancer-related expenditure between the highest and lowest-expenditure quintiles. Treatment factors explained more variation across the HRRs. Adjustment for whether different treatments were used (e.g., chemotherapy: yes/no; radiation: yes/no) explained an additional 26.0% of the difference between the highest and lowest-expenditure HRR quintiles. In contrast, adjustment for specific treatment modalities (e.g., specific type of radiation) explained 36.4% of the variation. Variation in expenditures on radiation therapy contributed the most to the difference in total cancer-related expenditure between the highest and lowest-expenditure HRR quintiles. Conclusions: There is large regional variation in Medicare expenditures on initial breast cancer care, even after accounting for patient characteristics. Treatment factors (whether cancer therapies were used at all and the specific modality of therapy used) were important contributors to such regional variation. Future work exploring the relation between cancer treatment intensity, costs, and outcomes is warranted. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-07-05.</jats:p