Abstract P5-11-05: Influence of Demographic and Histopathological Characteristics on Compliance and Persistence in 4.923 Postmenopausal Women with Early Breast Cancer (EBC) - Results of the Patient's Anastrozole Compliance to Therapy Programme (PACT)
Authors: Hadji P , Harbeck N , Jackisch C , Blettner M , Lück H-J , Tesch H , Haidinger R , Windemuth-Kieselbach C , Zaun S , Kreienberg R. 
Published: April 2011

Introduction: According to recent retrospective studies, compliance to adjuvant endocrine therapy for early breast cancer (EBC) may drop below 70% after one year and to as low as 50% by year 4. The PACT-study aims investigate the effect of standardized information materials (brochures and motivational letters) to standard clinical care. Here we present the results for the primary endpoints compliance and persistence rates at 12 months as well as the influence of demographic and histopathological characteristics on compliance and persistence.

Methods: PACT is a prospective, randomised, parallel-group study with 60 months of follow-up (NCT00555867, sponsored by AstraZeneca Germany). Postmenopausal women on anastrozole (ANA) for hormone-receptor positive (HR+) EBC were randomized to routine clinical care alone or additional standardized information (educational arm) for the first 12 months of adjuvant therapy. Primary endpoints are compliance and persistence rates in the educational versus routine arm after 12 months. Secondary endpoints include influence of baseline demographic and histopathol. characteristics on compliance and persistence as well as influence of compliance on clinical outcome parameters (DFS, OS). Compliance is evaluated via patient questionnaires, prescription data and physician recall and was defined as intake of at least 80% of the total medication (292 ANA tablets in 12 months). Persistence is defined as“duration of time from initiation to discontinuation of therapy” (Cramer 2007). A patient was defined as persistent if the documentation supported the intake of ANA during the full first 12-months.

Results: PACT enrolled 4,923 patients at 109 breast centres and 1,361 registered specialist practices from Germany. 4,397 patients were evaluable for baseline characteristics. 2,707 patients had a visit documented at 12 months (≥9 to 18 months) and were evaluable for the primary endpoint. No difference in compliance could be shown between the standard (88.2%) and educational arm (88.3%) at 12 months (p=0.95, Fisher's exact test). In a modified analysis classifying patients not attending for a follow-up visit after 12 months as non-compliant, the compliance rate in both arms was sign. lower with 53.9% in the standard and 55.1% in the educational arm, yet no significant intergroup difference (p=0.43). Persistence rates were 40.3% for the standard and 43.0% for the educational arm (p=0.17). Influence of baseline demographic and histopathological characteristics on compliance and persistence are currently under review and will be presented at the meeting. Conclusion: The addition of standardized information materials to standard clinical care did not lead to increased compliance or persistence rates at 12 months. Data on the influence of baseline demographic and histopathological characteristics on compliance and persistence will be presented. PACT represents the largest prospective study to evaluate the influence of educational materials and baseline demographic and histopathol. characteristics on compliance and persistence to adjuvant endocrine therapy in postmenopausal patients with HR+ EBC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-11-05.