Self-Reported Compliance With Adjuvant Endocrine Therapy in Young Women With Hormone Receptor-Positive Early Breast Cancer: A Real-World Study from a Tertiary Cancer Center in India.

BACKGROUND

Compliance with adjuvant endocrine therapy (ET) is crucial in hormone receptor-positive (HR+) early breast cancer (EBC), yet data from low- and middle-income countries (LMICs) remain scarce. This study evaluates compliance rates, identifies barriers to adherence, and assesses the impact on event-free survival (EFS).

PATIENTS AND

METHODS

This retrospective cohort study included 704 women aged 18 to 40 years with HR+ EBC treated at Tata Memorial Hospital, India, between 2015 and 2017. Compliance was assessed using a structured patient-reported questionnaire and was primarily defined as intake of ≥80% of prescribed ET therapy doses. Patients who completed at least 6 months of therapy were included in the primary compliance analysis. Factors associated with noncompliance were evaluated, and survival outcomes were compared between compliant and noncompliant groups.

RESULTS

Among 653 evaluable patients, 436 (66.7%) were compliant with ET, and 217 (33.3%) were noncompliant. The most common justifiable barrier to noncompliance was treatment-related adverse effects (67.7%). Nonjustifiable barriers included economic barriers (53.9%), perception-related barriers (49.1%), and behavioral barriers (44.7%). Behavioral and economic barriers remained independently associated with noncompliance on multivariable analysis. At a median follow-up of 72.8 months (interquartile range 70.2-75.5), median EFS was not reached in the compliant group and was 86.9 months (95% confidence intervals [CI]: 64.5-NR) in the noncompliant group (P = .004). The estimated 5-year EFS was significantly higher among compliant patients compared with noncompliant patients [64.3% (95% CI: 59.6%-69.5%) vs. 53.4% (95% CI: 46.7%-60.9%)]. On Cox regression analysis, noncompliance was independently associated with inferior EFS (hazard ratios 1.44, 95% CI 1.12-1.86; P = .005).

CONCLUSION

Noncompliance with ET is a clinically significant predictor of inferior outcomes in young women with HR+ EBC. Treatment-related toxicities were the most frequently reported barrier, while behavioral and economic barriers emerged as the principal independent predictors of noncompliance. Structured survivorship-focused interventions, including patient education, toxicity management, psychosocial support, and adherence monitoring strategies, are essential to improve long-term compliance and survival outcomes.