OBJECTIVES:

Breast cancer treatment is associated with complications such as pain, fatigue, nausea, diarrhea, and more. Breast cancer patients may also suffer from other unrelated comorbidities. These complications and comorbidities may lead to differences in patient-reported outcomes (PROs). We examined differences in PROs among breast cancer patients in Japan depending on their treatment for other conditions.

METHODS:

Data from the 2022 Patient Mindscape® survey was used, which is a nationwide survey among 500,000+ persons in Japan undergoing drug treatment for 80+ conditions. Persons that reported undergoing drug treatment for breast cancer within the past year were included. Health-related quality of life (HRQoL) and treatment satisfaction were considered for those that only underwent drug treatment for breast cancer and those that also underwent drug treatment for another condition from among the conditions included in survey.

RESULTS:

1,682 breast cancer patients treated with drug therapy were identified. Among those, 35% were treated only for breast cancer and 65% were also treated for another condition. Based on the EQ-5D-5L and EQ-VAS measures, those treated only for breast cancer reported better HRQoL, on average, than those also treated for another condition. HRQoL was lowest, on average, for those also treated for migraines, lower back pain, chronic constipation, or insomnia. On average, breast cancer treatment satisfaction was similar for both groups. However, breast cancer treatment satisfaction varied depending on the complication or comorbidity experienced and was lowest for those also treated for glaucoma / ocular hypertension, chronic constipation, diabetes, or migraines.

CONCLUSIONS:

PROs for breast cancer patients vary depending on their other conditions. Further research is needed to understand how complications and comorbidities can affect the perceived benefit of new treatments. Differences in HRQoL between groups (e.g., treatment and non-treatment arms) may not be informative unless the prevalence of other conditions is adequately accounted for.