Locally advanced breast cancer (LABC) is a subset of breast cancer with locoregional progression without distant metastasis. The multimodality treatment (surgery, chemotherapy, radiotherapy, hormonal and targeted therapy if required) could significantly improve results in this specific group of patients. The complex and multiple options of treatment with similar mortality rates but different outcomes depending on the patient's desires, preferences and social environment require aid to facilitate the individual patient's decisions (e.g. Decision Aids (DAs) targeting patients considering primary or adjuvant treatment in LABC). In this context, DAs have been proven fundamental to help patients and clinicians share and agree on the best value option. The current systematic review aimed to evaluate the existing DAs related to these patients with LABC and identify current status and possible improvement areas (possible scarcity and heterogeneity of instruments, the status of their development, explanation of their purpose,…). No previous systematic reviews have been published on this topic. Following Prospero registration no: CRD42021286173, studies about LABC DAs were identified, without data or language restrictions, through a systematic search of bibliographic databases in December 2021. Quality was assessed using Qualsyst criteria (range 0.0-1.0). The quality of the 17 selected studies ranged from 0.46 to 0.95. Of them, 14/17 (82%) were DAs about treatment, only one (6%) about diagnosis, and 2/17 (12%) about the employment of DAs. No screening or follow-up DAs were retrieved. Twelve (70.6%) DAs were online tools. They varied broadly regarding their characteristics and purposes. Most of the studies focused on developing and testing different DAs (5/17; 29.4%) and their impact (7/17; 41.2%). Only 4/17 (23.5%) analysed their implementation and cost. These instruments have proven to improve patient's knowledge and decision-making, decrease patient anxiety, and patients tend to undergo treatment. However, nowadays, there is still a need for further research and consensus on methodology to develop practical DAs.
Keywords: Shared decision making; breast cancer; breast cancer treatment; decision aid; decision support tools; locally advanced cancer.