The ETERNITY study is an international, multicenter, observational study that aims to follow up patients who have participated in a GBG trial for early breast cancer, even after the study has officially ended, in order to collect long-term data on survival, late or delayed adverse events, in addition to information related to pregnancy, fertility and other parameters impacting quality of life.

This is a prospective and retrospective, international, multicenter, non-interventional, observational study for collection of long-term safety and efficacy parameters of former GBG study participants of prospective clinical trials on early breast cancer.

Patients with prospective data collection will be informed about the registry by the treating physician at the study site. After written informed consent (which may already be included in the main and/or biomaterial informed consent form of the respective clinical study) for data and biomaterial collection, the registration form will be filled out completely within the GBG electronic data capture system (MEDCODES®). Inclusion and registration can take place after informed consent of the patient. However, documentation of follow-up should start after the regular end of study or with the start of the follow-up period, as defined in the respective study protocol.

A correlation of the follow-up registry database with the respective study databases is possible via the patient identification number of the participant. Consequently, the long-term effects of the study therapy can be calculated per therapy group, and the effectiveness can be correlated with possible late-onset toxicities.

Post-study long-term outcome follow-up will be assessed according to local/national guidelines for standard follow-up examinations and post-treatment surveillance. Data should be documented at least once a year in the registry.

Relapse and safety assessment will be performed, and survival status will be collected in all registered patients. Here, the investigator may conduct evaluations or assessments within regular follow-up visits. However, telephone contact or contact in writing with the patient or treating physician or relatives in case of death is also acceptable. Imaging tests (e.g., mammography and/or staging workup) are recommended according to local/national guidelines for follow-up and in case of symptoms suspicious for locoregional or distant relapse.

Information to be collected include:

• Date and site of first non-invasive local recurrence, first invasive local recurrence, first contralateral breast recurrence, first regional recurrence, first distant recurrence
• Date and diagnosis of secondary malignancies
• Date and cause of deaths
• Pregnancies after study participation and their respective outcome
• Anti-hormonal therapies in HR+ breast cancer patients
• Further anti-cancer treatments after study participation
• Long-term adverse drug reactions of the respective study treatments

In case of disease recurrence, it is recommended to confirm diagnosis by histological examination. If performed, an FFPE tumor tissue block from the metastatic lesion should be provided to GBG.

It is allowed and recommended to register patients in parallel in the GBG self-reporting registry (available only in German) that will allow follow-up and long-term efficacy evaluations beyond the end of the respective study by the patients themselves.

STATISTICS

This is an observational study for collection of long-term safety and efficacy parameters of former GBG study participants. As long-term outcomes and late-onset toxicities are also secondary objectives in all prospective clinical studies of the GBG, statistical methods will adhere as much as possible to methods described in the respective clinical trial protocols.

For the analysis, data from the corresponding clinical trials (e.g., baseline characteristics, short-time efficacy, and toxicity parameters, already collected follow-up data, etc.) will be merged with the registry data.

DATA HANDLING, MANAGEMENT AND QUALITY ASSURANCE

The GBG EDC system MEDCODES® will be maintained by GBG Forschungs GmbH for all study sites.

Data management, which comprises CRF design, database and application hosting, data entry, and data validation, will be performed by GBG Forschungs GmbH for all study sites. GBG Forschungs GmbH will provide the investigator site with the web base EDC system MEDCODES® that is validated and conforms to 21 CFR Part 11 requirements. Investigator site staff will not be given access to MEDCODES® until they have been trained on the EDC system.

Visual and computerized methods of data validation are applied in order to ensure accurate, consistent, and reliable data for the subsequent analyses.

All communication between MedCODES® and the clients is securely encrypted (Secure HTTP).

In order to protect patient confidentiality, each participating patient is assigned a unique GBG patient identification number. Instead of the true patient identity, the pseudonym is used in all communication between the trial site and the GBG Forschungs GmbH. A correlation of the follow-up registry database with the respective study databases is possible via the patient identification number of the participant.

Every user is provided with a unique username and a unique password. Every user is assigned to a user group which represents their role in the CRF workflow. Access control is based on user name, group. Therefore, users can only access those datasets necessary for them to fulfill their role in the CRF workflow ("need to know basis").

Inclusion criteria:

• Participation and treatment in a GBG clinical trial for early breast cancer.
• Prospective registration: Written informed consent according to local regulatory requirements prior to data and biomaterial collection.

Exclusion criteria:

• Participation and treatment in a non-GBG clinical trial for early breast cancer.
• Patients with advanced or metastatic breast cancer who have participated and received treatment in a GBG clinical trial.

Patients who participated and received treatment as part of a GBG clinical trial for early breast cancer.