Female breast cancer is still the most frequent type of cancer in Europe with 21 per 100,000 women .The EORTC QLQ-BR23 was one of the first modules developed to be used in conjunction with the core questionnaire EORTC QLQ-C30 and was published in 1996. Since the beginning of the work on the EORTC QLQ-BR23 some 20 years ago, much knowledge has been gathered about the epidemiology of breast cancer, and major advances have been made with regard to diagnostic and therapeutic options. Therefore, the EORTC Quality of life group decided to update the BC23. A phase 1 to 3 module development project has been completed. This resulted in a 45 item module, retaining 23 of the original items and adding 22 new items, particularly tapping into the side effects of new systemic and local therapies.

The aim of the Phase 4 study is to test the scale structure, reliability, responsiveness to change, and validity of the EORTC QLQ-BC45 in conjunction with the EORTC QLQ-C30 in patients diagnosed with breast cancer. Participants will be enrolled in four groups according to their disease stage (1. local/locally advanced disease, 2. metastatic disease, 3. follow up. Various combinations of therapies are permissible.

According to sample size calculations, we will include a total of N =490 patients from 12 countries.

Participants will be invited to complete the QLQ-C30 and the QLQ-BC45, followed by the Debriefing Questionnaire. Data of all patients will be used to evaluate the scale structure, internal consistency, convergent and discriminant validity. A subgroup of follow up patients with no evidence of disease (no change in health status) will be invited to complete the QLQ-C30 and the QLQ-BC45 for a second time one to two weeks later for the test-retest analysis. A subgroup of patients from the local/ locally advanced breast cancer group (who have had change in disease or treatment status after the first assessment) will be invited to complete a second set of questionnaires for the response to change analysis. Sociodemographic and clinical data will be recorded using standardized case report forms (CRF).

Inclusion Criteria:

• Adult females aged 18 years or over
• Histologically confirmed diagnosis of breast cancer (any type) with no previous primary or recurrent tumour
• Receiving or have previously received curative or palliative treatment.
• Able to understand/speak English and complete the questionaires
• Have the capacity/mental fitness to give written informed consent and complete the questionnaires.

Exclusion Criteria:

• Male gender or transgender
• Inability to understand/speak English and complete the questionnaire
• Patients with any psychiatric condition or cognitive impairment, as determined by the treating physician, that would hamper participation.

Breast cancer patients