Measurements

Disease-specific aspects of HRQoL were assessed by the European Organization for Research and Treatment of Cancer Breast Cancer–Specific Quality of Life Questionnaire (EORTC QLQ-BR23). The 23-item questionnaire consists of four functioning items/scales (body image, future perspective, sexual functioning, and sexual enjoyment) and four symptom items/scales (arm symptoms, breast symptoms, systemic therapy side effects, and upset by hair loss). The conditional questions on sexual enjoyment and upset about hair loss are only completed if the participant is sexually active or has hair loss, respectively. Answers range from 1 (not at all) to 4 (very much) for all items. Linear transformation of raw scores to scales of 0–100 was performed according to the EORTC scoring manual (Fayers et al. 2001). High scores on the functioning scales indicate better functioning. On the symptom scales, a high score represents a greater burden.

The participating cancer registries provided additional clinical information such as year of diagnosis and cancer stage. Information on treatment and on recurrence, metastasis or new cancer since initial diagnosis were assessed via self-report. “Active disease” was defined as either any self-report of recurrence, metastasis or second primary cancer after the study cancer.