Abstract P2-07-02: Concordance with National comprehensive cancer network (NCCN) metastatic breast cancer guidelines and impact on overall survival
Authors: Rocque GB , Williams CP , Jackson BE , Halilova KI , Pisu M , Andres F , Smita B 
Published: March 2017

Introduction:Payers are implementing reimbursement restrictions for non-guideline based care. Limited information exists regarding real-world concordance with guidelines for metastatic breast cancer (MBC) treatment. Further, the impact of non-concordance on mortality is unknown. We address these gaps by using the Surveillance, Epidemiology, and End Results (SEER) Program-linked Medicare database to evaluate national concordance with NCCN guidelines and the association between concordance and mortality.

Methods: From 2007 to 2013, women with de novo (n=988) or recurrent metastatic breast cancer (n=5651) were evaluated for concordance of first-line systemic therapy (hormonal therapy, chemotherapy, and Her2-targeted therapy) with NCCN guidelines. Concordance was defined as receipt of single agent or combination treatments listed on NCCN guidelines. Non-concordant treatments were grouped into 5 categories: single-agent HER2-targeted therapy (33%), adjuvant regimens used in the metastatic setting (12%), therapy mismatched with ER/HER2 status (12%), non-approved bevacizumab regimens (10%), and other miscellaneous reasons (33%). Multivariable logistic regression was used to identify predictors of non-concordance. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression to compare all-cause mortality associated with non-concordant vs. concordant treatment adjusted for receptor status, comorbidities, age, race, poverty level, entitlement reason, and treatment year.

Results: Mean age at MBC diagnosis was 69y; 77% were white. Median follow-up was 1.2 years. The prevalence of non-concordant first-line systemic therapy was 19% for de novo MBC and 18% for recurrent MBC. Younger age, hormone-receptor negative status, and Her2-positive status were associated with non-concordant treatments for Stage IV and recurrent MBC patients (p&lt;0.001). Higher poverty by census tract was associated with non-concordance in recurrent MBC (p&lt;0.05). The most frequent category of non-concordant treatment in de novo MBC was use of adjuvant regimens in Stage IV MBC (43%) and use of single-agent HER2-targeted therapy (31%) in recurrent MBCs. Adjusted overall survival was similar for patients with de novo MBC receiving concordant and non-concordant treatments (HR 0.88, CI 0.72-1.65). Mortality was modestly increased for patients with recurrent MBC receiving non-concordant care (HR 1.12, CI 1.02-1.22); however, substantial differences were noted by category of non-concordance. Compared to concordant treatment, single-agent HER2-targeted therapy was associated with decreased risk of mortality (HR 0.78, CI 0.68-0.91). Increased mortality was observed for non-approved bevacizumab use (HR 1.79, CI 1.44-2.22) and other miscellaneous regimens (HR 1.42, CI 1.26-1.60). Mortality for therapy mismatched with ER/HER2 status was similar to concordant treatment (HR 1.13, CI 0.88-1.44).

Conclusions: In the first-line setting, treatment inconsistent with NCCN guidelines remains common (18%). Overall mortality was not substantially higher among non-concordant patients. However, mortality risk varied (in both directions) by category of non-concordance. These findings may provide an opportunity for considering refinement of NCCN guidelines.

Citation Format: Rocque GB, Williams CP, Jackson BE, Halilova KI, Pisu M, Andres F, Smita B. Concordance with National comprehensive cancer network (NCCN) metastatic breast cancer guidelines and impact on overall survival [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 P2-07-02.