Epidemiology and Choice of Treatment in the Adjuvant Setting of Hormone Receptor Positive Her2 Negative (Hr+/Her2-) Breast Cancer (Bc), Evidence from Administrative Databases, with a Focus on the Sarscov2 Pandemic

ABSTRACT

Background: Real-world evidence through secondary use of data (SUD) in oncology is gaining increasing interest, to better understand cancer epidemiology and provide insights into treatment patterns in daily practice. This study evaluates incidence of HR+/HER2- early BC (eBC) and its management in clinical practice through SUD and gauge the impact of the SARS-COV2 pandemic. Method(s) This observational retrospective analysis integrates administrative databases for healthcare resources consumption (pharmaceuticals, hospitalizations, diagnostic tests and specialist visits databases) from a sample of Italian Local Health Units, based on 15 million inhabitants across Italy. Patients with >=1 hospitalization discharge diagnosis for BC, with surgical intervention and HR+ status (determined by coding for HR+ status or by presence of endocrine therapy) between 01/2010-06/2021 were included. Patients with at least one prescription of anti- HER2 monoclonal antibodies were excluded. Patients were classified by menopausal state through prescription for the gonadotropin-releasing hormone analogues (GnRHa). Incidence was calculated during all study period. Result(s) Incidence rate has a slight upwards trend, as expected, ranging from 53.9 in 2013 to 62.7 in 2019 per 100,000 health-assisted subjects. Incidence in 2020 is 49.2 per 100,000 (table 1 for quarter split). As for adjuvant therapies, 31,836 patients were included in the analysis of which 5343 (16.8%) were classified as premenopausal. Mean age was 64.5 years. Most patients (78.8%) were treated with only adjuvant endocrine therapy (ET). 16.5% of the sample received adjuvant chemotherapy (CT). CT treatment was more prescribed in premenopausal patients. CT treatment was started within 12 weeks of surgery for 3.9% of the sample. Most patients (12.7%) started it between 12 weeks and 24 weeks. Conclusion(s) SUD can provide lots of information with the right queries. The analysis confirms the slight increase in incidence observed by national registries and provides an estimate of the impact of SARS-COV2 with a 22% reduction of breast surgery in 2020. Administrative data can be used to assess clinical variables (e.g. premenopause through GnRHa prescription), and could be further explored for disease stage through axillary dissection, and recurrence through prescription of therapies used in metastatic setting.