ESMO Congress 2024 | OncologyPRO

Abstract 376P

Background

Optimal treatment outcomes in breast cancer heavily rely on patient adherence to oral anticancer medications (OAMs). This study investigates the differences in adherence rates between metastatic and non-metastatic breast cancer patients using a comprehensive dual-method approach.

Methods

In this cross-sectional study at the National Cancer Institute, Cairo University, 500 breast cancer patients were categorized into metastatic (45.6%) and non-metastatic (54.4%) groups. Adherence was measured using the Morisky Medication Adherence Scale (MMAS-8) and the Medication Possession Ratio (MPR), with nonadherence defined as an MMAS-8 score < 8 or an MPR < 80 %. Data collection was augmented by patient interviews and examination of outpatient pharmacy dispensing records.

Results

Adherence rates were 46.4% as per MMAS-8 and 71% according to MPR. Specifically, in the non-metastatic group, MMAS-8 revealed a 28.3% adherence rate, while MPR showed 75.4%. Metastatic patients displayed significantly higher adherence (p<0.001). There was a notable inverse correlation between adherence and the severity of side effects like musculoskeletal pain, neurological symptoms, fatigue, and hot flushes (p<0.001). Additionally, adherence varied with treatment duration, with shorter periods associated with better adherence.

Conclusions

The study confirms that adherence to OAMs is significantly affected by both the metastatic status and the severity of side effects. It highlights the urgent need for enhanced educational and management strategies tailored to the specific challenges faced by breast cancer patients, especially those dealing with severe side effects. Ongoing research should focus on developing and testing targeted interventions to improve adherence in these patient groups.