Survival rates for breast cancer (BC) patients are increasing, but improved survival is often obtained at a cost, with more intense treatments resulting in persistent symptoms and late effects. These include treatment-specific loco-regional symptoms, e.g., surgery and radiotherapy-induced lymphedema and fibrosis, late effects after systemic treatments, e.g., chemotherapy-induced neuropathies and premature menopause, and general bio-behavioral late effects observed across cancer types and treatments, e.g., fatigue, pain, sleep disturbance, depression, fear of cancer recurrence, and cognitive impairment. While many BC patients experience improvements in these symptoms after completing primary treatment, substantial subgroups of BC survivors develop persistent or even exacerbated symptoms, severely affecting their daily physical, mental, and social functioning and well-being.
The limitations of the available research in late effects include small samples of convenience, cross-sectional designs, and longitudinal studies, mainly capturing overall changes in symptom severity over time. We, therefore, only have limited knowledge about who is at heightened risk of developing persistent late effects, how their symptoms develop over time, the mechanisms driving such changes, and how best to prevent and treat them. The clinical implications are that patients are rarely asked about and seldom treated for their late effects. On this background, it has become increasingly clear that there is a need for systematically collected patient-reported outcome (PRO) data on symptoms and late effects across the cancer treatment and survivorship trajectory.
Supported by the Danish Cancer Society, the Danish Breast Cancer Group Center and Clinic for Late Effects (DCCL) was established in 2018. A core aim was to develop and evaluate a smartphone-based application for collecting national PRO data on late effects after breast cancer treatment (DCCL-PRO). Patients are asked to download the DCCL-PRO app and complete a baseline questionnaire prior to surgery. Based on their personal treatment plan, patients are then prompted to complete questions on treatment-specific and general symptoms and late effects at various intervals throughout their treatment and follow-up trajectory. DCCL-PRO includes individual questions and validated scales assessing (a) sociodemographic data, (b) health behaviors, physical function, and comorbidity, (c) loco-regional and general physical symptoms (e.g., lymphedema, menopausal symptoms, pain, neuropathies), (d) general symptoms and late effects (e.g., fatigue, depression, anxiety, fear of cancer recurrence, insomnia, cognitive function, sexual adjustment, and body image), (e) work-related difficulties, and (f) emotional and informational support and self-efficacy for managing symptoms. The DCCL-PRO is personalized, ensuring that patients and survivors are only presented with relevant questions and scales, minimizing respondent burden. DCCL-PRO is also interactive. Based on pre-defined clinical cut-offs, patients and survivors are given feedback and advice on how to cope with their symptoms and when to seek help. Finally, prior to consultations, an accompanying DCCL-PRO Clinician App provides clinicians with an overview of the collected PRO data for each patient, together with information about late effects and examples of relevant advice.
The DCCL-PRO has been pilot tested, and qualitative interviews with 30 patients revealed high levels of satisfaction with the project and the app, its content, the feedback, and the interactive user interface. The app is currently being stepwise implemented in departments across Denmark. Challenges include regional differences in consultation and treatment schedules, opportunities for recruiting and informing patients about the app, and the resources available for helping patients download and access the app.
When DCCL-PRO is successfully implemented, the perspectives are manifold: First, we aim to integrate the data collected with DCCL-PRO with the DBCG clinical database, thereby delivering on the goal of the Danish National Cancer Plan IV to ensure integration of PRO data in the national clinical cancer databases. Second, such data will provide researchers with the population-based data needed to develop AI-based models predicting who is at heightened risk of developing late effects. Third, the accompanying DCCL-PRO Clinician App makes continuously updated information available to clinicians about late effects experienced by their patients, thereby informing the consultation. Fourth, a nationally implemented DCCL-PRO will deliver population-based high-quality longitudinal data informing randomized controlled trials of interventions to prevent and treat late effects after cancer and cancer treatment. Finally, the knowledge obtained will guide the development of national guidelines on late effects after cancer and identify areas where more research is needed.