The survival advantage of HER2-positive breast cancer from targeted treatment is commonly undermined by catastrophic health expenditure (CHE), particularly in resource-limited areas. Recognizing that financial catastrophe leads to non-adherence to treatment and dissaving practices, we examined the out-of-pocket (OOP) expenses of patients with HER2-positive breast cancer.

The study aimed to estimate the median total per-cycle out-of-pocket expenditure of HER2-positive breast cancer treatment from the patient perspective, in public and private clinics, evaluate the association of catastrophic health expenditure with non-adherence to treatment, and describe dissaving practices.

This was a cross-sectional micro-costing analysis of the treatment of HER2-positive breast cancer from the patient perspective from a tertiary cancer center and select private clinics in the Philippines. Random sampling of patients with HER2-positive breast cancer was done. Using a validated questionnaire, a guided interview was administered. Catastrophic health expenditure was estimated as having OOP of >20% of the household income. OOP costs were assessed retrospectively from the time of confirmed HER2 diagnosis up to the date of survey, while household income referred to the corresponding period. The proportion of patients experiencing catastrophic health expenditure was computed. Fisher's exact was used to assess for any association between CHE and non-adherence to treatment. Descriptive statistics were used to report dissaving practices. All statistical analyses were performed using Stata analytical software version 12.

A total of 101 patients participated in the study. The mean age of participants from the tertiary cancer center and private clinics were 52 and 58 years old respectively. Patients from the private clinics had a median total OOP expenditure of PhP 54,737.06 (IQR = PhP 102,670.00), compared with patients from tertiary cancer center who had a median total OOP expenditure of PhP 13,920.66 (IQR = PhP 20,830.00). The overall prevalence of CHE (90.9%, 95% CI 0.81, 0.95) and nonadherence to treatment with trastuzumab (79%, 95% CI 0.70, 0.87) were high, and similar in both groups. A number of dissaving practices such as resignation from work, borrowing money from friends, selling assets were observed.

The high rate of CHE and treatment delay among patients with HER2-positive breast cancer were not addressed by the existing cancer programs. Most OOP expenditure was for trastuzumab. Current cancer support programs have potential to address the financial impact of their treatment.