Objectives:
Doxorubicin remains a key component chemotherapeutic agent, yet its use is limited by dose-dependent cardiotoxicity. Data from South Asian populations, particularly within routine clinical practice in tertiary care settings, remain scarce. This study aimed to determine the incidence, patterns, and predictors of doxorubicin-related cardiotoxicity among adult cancer patients.

Methods:
A retrospective cohort study was conducted at the Pakistan Institute of Medical Sciences (PIMS), Islamabad, including adults (≥18 years) who received doxorubicin between January and December 2024. Patients with known pre-existing cardiovascular disease were excluded. Demographics, comorbidities, cumulative doxorubicin dose, and baseline/follow-up echocardiography were reviewed. Cardiotoxicity was defined as a ≥10% decrease in left ventricular ejection fraction (LVEF) to <50% and/or development of symptomatic heart failure. Descriptive statistics and multivariable logistic regression were used to identify independent predictors.

Results:
Among 312 patients (mean age 51.6 ± 12.4 years; 62% female), 38 (12.1%) developed cardiotoxicity. Of these, 28 (73.7%) experienced asymptomatic LVEF decline, while 10 (26.3%) developed symptomatic heart failure. The mean cumulative doxorubicin dose in affected patients was 396 ± 45 mg/m². Independent predictors included:

Age >55 years (OR 2.1; p = 0.01)

Hypertension (OR 1.8; p = 0.03)

Borderline baseline LVEF (50–55%) (OR 3.4; p < 0.001)

Cumulative dose >350 mg/m² (OR 2.6; p = 0.02)

Early initiation of cardioprotective therapy (ACE inhibitors and beta-blockers) resulted in partial LVEF recovery in 58% of affected patients.

Conclusion:
Doxorubicin-induced cardiotoxicity occurred in approximately one in eight patients in this tertiary care cohort, with both clinical and subclinical presentations. Higher age, hypertension, borderline baseline LVEF, and greater cumulative exposure were strong predictors. These findings highlight the need for dedicated cardio-oncology pathways and adherence to structured cardiac monitoring protocols to facilitate early detection and management.