A Cluster Randomized Trial of a Breast Cancer Treatment Decision Aid for Women 70+ with Low-Risk Stage I Breast Cancers - Widespread use of mammography screening and population aging has led to many women >70 years being diagnosed with Stage I, estrogen receptor-positive (ER+), HER2-, breast cancer. Historically, standard treatment included mastectomy or breast-conserving surgery (BCS) with sentinel lymph node biopsy (SLNB), with BCS followed by radiotherapy (RT); and endocrine therapy following locoregional therapy. However, trials have found that omitting RT after BCS and/or omitting SLNB in women >70 with these breast cancers does not affect their survival and may reduce treatment morbidity. Thus, guidelines include omission of RT after BCS and of SLNB in women >70 with these breast cancers as appropriate. Despite this, around 55% of women >70 with these breast cancers receive RT post BCS and 60% receive SLNB. Possibly because few breast surgeons are trained to engage older women in shared decision making (SDM) around treatment. SDM is a process where clinicians and patients work together to make treatment decisions based on the best available data and patients values and preferences. Also, no decision aids (DAs) were designed to inform women >70 about the benefits/harms of their multiple treatment options and the interplay of their health, life expectancy, values and preferences in these decisions. SDM supported by DAs may improve decision quality while reducing overtreatment since well-informed patients often choose not to receive care associated with little benefit (low- value). Thus, our interdisciplinary team developed and pilot tested a SDM training program for breast surgeons and a promising treatment DA for women >70 newly diagnosed with Stage I, ER+, HER2-, breast cancer. We propose SDM POSSIBLE (SDM for People Over Seventy with Stage I Breast cancer to Learn and Engage), a multisite surgeon-level cluster randomized trial to test the effects of our intervention (surgeon SDM training plus patient DA). We aim to randomize 22 breast surgeons per arm to test training surgeons in SDM and sending their patients (560 per arm) the DA on patient treatments and outcomes (Aim 1). We hypothesize that significantly fewer patients cared for by intervention arm surgeons will receive any low-value care defined as mastectomy, SLNB, or RT after BCS within 6 months of their first surgical encounter (primary outcome, assessed administratively via chart abstraction) and there will be no difference on breast cancer recurrence or survival, and overall survival per arm over 3.5 years. In Aim 2 we aim to recruit 340 patients (or caregivers for those with incapacity) included in Aim 1 to complete 1-week and 6-month surveys to learn our intervention’s effects on participant-reported SDM quality, knowledge, decisional conflict, and quality of life and our interven- tion’s cost-effectiveness at 6 months. In Aim 3, we will examine our intervention’s effect on surgeon SDM self- efficacy. In Aim 4, we will conduct >22 qualitative interviews with participants at 1-year and at study’s end and with clinical staff at study’s end to learn contextual factors influencing intervention implementation. Our novel intervention will likely lead to women >70 receiving more person-centered care and thus to better outcomes.
