An intervention study based on real-world data to improve quality of life after breast cancer treatment

Many breast cancer patients suffer from cancer-related fatigue (CRF) during and after primary treatment. Up to one-third experience chronic CRF, which can persist for as long as 10 years post-treatment. Fatigue significantly impacts patients’ quality of life, often hindering daily functioning. This can affect social lives, family relationships, and the ability to work. Notably, around 30% of fatigued breast cancer patients do not return to full-time work after completing cancer treatment.

Unfortunately, no definitive treatment currently exists for CRF. However, growing evidence suggests that physical activity has a positive effect on fatigue both during and after cancer treatment. Individually tailored physical activity is the recommended approach, and in Norway, the organisation Active Against Cancer has established several activity centres (Pusterom) across the country. These centres offer cancer patients individualised physical training and guidance from physiotherapists.

To explore how personalised, REBECCA-assisted follow-up can improve the quality of life for breast cancer patients, the REBECCA-Inter-QoL study (REBECCA-2) uses digitally collected real-world data. This includes information on physical activity, sleep, and stress levels from commercial smartwatches, as well as GPS location data from the REBECCA mobile app. The study is conducted at the Department of Hematology and Oncology, Stavanger University Hospital (SUH), with additional collaboration with physiotherapists at Pusterommet to assess whether increased physical activity can improve fatigue symptoms.

Study design

The REBECCA-2 study was launched at SUH, recruiting breast cancer patients visiting the clinics between November 2022 and February 2024. All breast cancer patients, regardless of cancer type, were invited to participate. Patients who consented were recruited at the time of diagnosis at the Department of Breast and Endocrine Surgery. Following the completion of primary treatment, patients were randomly assigned to one of two groups:

• The control group: Patients in this group receive standard follow-up care as outlined in Norway’s National Guidelines. This includes regular visits with an oncologist every six months.

• The experimental group: Patients in this group receive the REBECCA system (smartwatch and mobile app) after completing treatment, enabling data collection for 12–18 months. Initially, participants attend biannual oncologist visits. However, if the REBECCA system detects a decline in their quality of life—indicating potential fatigue development—additional visits are scheduled for early intervention. Patients experiencing severe fatigue are referred for individually tailored physical training at Pusterommet.

Participants initially provide data for 12 months, with the option to extend their involvement for an additional six months. The study collects continuous digital data, supplemented by patient-reported outcome measures (PROMs)—the gold standard for quality of life assessments in clinical studies. Additionally, blood and stool samples are collected to investigate biomarkers that might provide new biological insights into CRF, as the mechanisms behind fatigue remain poorly understood. These biological samples are analysed at the Department of Pathology, SUH.

To date, 80 patients have been recruited, with one participant having completed the full 18-month study period. We extend our sincere gratitude to all patients who have contributed to the REBECCA-2 study for their invaluable effort and participation.