Abstract 31: Does Receipt of Resource-Adapted Guideline-Concordant Breast Cancer Care Improve Outcomes? A Retrospective Study of 517 Breast Cancer Patients in Southwest Nigeria
Authors: Dare Anna , Olasehinde Olalekan , Bernardo Matteo Di , Wuraola Funmiola , Omisore Leye , Omoyiola Tosin , Owoade Israel , Ogunyemi Mary , Kahn Rivka , Kingham T Peter , Alatise Olusegun , Romanoff Anya 
Published: June 2023

Abstract
Purpose: The NCCN Harmonized Guidelines for sub-Saharan Africa (SSA) provide evidence-based recommendations for standardized breast cancer (BC) care that are resource-appropriate, regionally developed and endorsed. This study aims to evaluate the proportion of BC patients receiving guideline concordant care in Southwest Nigeria, and their survival outcomes.
Methods: A retrospective analysis was performed of consecutive patients diagnosed with non-metastatic BC at Obafemi Awolowo University Teaching Hospital, a public referral hospital in Ife, Nigeria. The NCCN Harmonized Guidelines for SSA - Breast Cancer, version 4.2021 were used to define concordant care, following the minimum practice standards for lower resource environments. Concordance was estimated with exact 95% confidence intervals. Overall survival (OS) was estimated with Kaplan Meier methods.
Results: Between January 2016-December 2021, 517 patients were diagnosed with non-metastatic BC (stage I/II: n=101, 20%; stage III: n=416, 80%). Median age was 49y. Diagnostic work-up was guideline-concordant in 6.4% (n=33/517; 95%CI 4.4-8.8%). 98% (n=508/517) received a pre-treatment tissue diagnosis, 86% (n=373/435) completed an appropriate metastatic work-up, but only 18% (n=91/516) underwent breast imaging and 28% (n=142/517) had hormone receptor testing. Locoregional treatment concordance was 3.7% (n=19/517; 95% CI 2.2-5.7%) overall. 43.1% (n=223/517) of patients underwent surgery and 4.3% (n=22/517) received adjuvant radiation where indicated. 24% (n=122/517) received adjuvant chemotherapy. Guideline concordance was highest for neoadjuvant systemic treatment (55%, n=181/329; 95%CI 49-60%), followed by hormonal therapy where hormone receptor status was known (47%, n=24/51; 33-62%). Median follow-up was 17 months (IQR: 3-40). 3-year OS was 70% (59-84%) for stage I/II patients and 46% (40-53%) for stage III. Improved OS was seen across all major treatment categories for stage III patients who received guideline-concordant care compared to those who did not.
Conclusion: Concordance with resource-adapted, regional practice guidelines for BC was low. Under-utilization of surgery, limited access to radiation and low rates of hormone receptor testing/therapy were key drivers of this finding. The association of concordant care with improved OS supports the utility of the guidelines & identifies areas where investments to strengthen care through guideline adherence could lead to better survival outcomes.
Citation Format: Anna Dare, Olalekan Olasehinde, Matteo Di Bernardo, Funmiola Wuraola, Leye Omisore, Tosin Omoyiola, Israel Owoade, Mary Ogunyemi, Rivka Kahn, T Peter Kingham, Olusegun Alatise, Anya Romanoff. Does Receipt of Resource-Adapted Guideline-Concordant Breast Cancer Care Improve Outcomes? A Retrospective Study of 517 Breast Cancer Patients in Southwest Nigeria [abstract]. In: Proceedings of the 11th Annual Symposium on Global Cancer Research; Closing the Research-to-Implementation Gap; 2023 Apr 4-6. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(6_Suppl):Abstract nr 31.