Abstract PO2-22-11: 'A sledgehammer to crack a nut' or 'the safer option'? Understanding decision making for and against oncoplastic breast conserving surgery as an alternative to mastectomy in women with early breast cancer: The UK ANTHEM study

Abstract Background: Oncoplastic breast conserving surgery (OPBCS) may allow women with breast cancer to avoid mastectomy, but many women continue to choose more extensive surgery even when breast conserving options are offered. Reasons for women’s procedure choices are unclear. The UK prospective multicentre ANTHEM study (ISRCTN18238549) aimed to explore the feasibility of undertaking a large-scale multicentre study comparing the clinical and patient-reported outcomes of OPBCS as an alternative to mastectomy in women offered both options. The qualitative phase of the study aimed to use semi-structured interviews to explore women’s perceptions of choice and to understand factors influencing decision making for and against OPBCS in early breast cancer. Methods: Women offered OPBCS as an alternative to mastectomy were eligible to participate in the ANTHEM study. Participants underwent their surgical procedure of choice and were followed up for 12 months. Semi-structured interviews were conducted with a purposive sample of women who elected to undergo either OPBCS or mastectomy with or without immediate breast reconstruction (IBR) at multiple UK centres to explore perceptions of choice, rationale for decision-making, and factors influencing procedure choice. Thematic analysis was used to explore the qualitative interview data. Sampling, data collection and analysis were undertaken concurrently and iteratively until data saturation was achieved. Results: Twenty-seven women from 12 UK breast units were interviewed. Of these, 12 elected to have OPBCS with volume displacement (n=7) or replacement procedures (n=5) and 15 chose mastectomy with (n=10) or without (n=5) IBR. Overwhelmingly, women’s decisions were guided by their surgical teams and their understanding and interpretation of the information they received from them. Indeed, although provision of choice was a pre-requisite for study entry, almost a third of women didn’t feel they had been offered meaningful choice as their surgeon recommended either OPBCS or mastectomy for them. Several women described how choice was unexpected as they had automatically assumed that they would need a mastectomy and expressed delight at being offered OPBCS as an alternative. Having choice and needing to make a decision about surgery, however, was a difficult experience for some women who reported finding the process challenging. Decision-making for and against OPBCS was underpinned by women’s perceptions of three key inter-related factors based on the information they received from their surgical teams: i) the effectiveness of OPBCS at removing all the cancer; ii) perceived longer term oncological safety and iii) practical issues. Almost all women described concerns about whether all the cancer would be removed by OPBCS, the need for further surgery for involved surgical margins and anxieties about cancer recurrence over time. Women who felt reassured that OPBCS was oncologically safe were happy to accept this option. Women who remained very anxious about incomplete excision and cancer recurrence were more likely to opt for mastectomy as a ‘safer’ option. Practical issues such as the perceived magnitude of the surgery and duration of the recovery were also important with many women choosing OPBCS as a less invasive or radical option than mastectomy. While many women described preferring to keep their breast and maintaining their femininity, only a minority of women referred to the cosmetic benefits of OPBCS as influencing their decision-making. Conclusions: Women’s decision-making for OPBCS vs mastectomy for breast cancer is complex and heavily influenced by the attitudes and beliefs of their surgical team. Adequate, high-quality, accurate information about surgical options including appropriate reassurance about the short- and long-term oncological safety of OPBCS is vital if women are to make fully informed decisions and feel confident avoiding mastectomy if this is an option for them. Citation Format: Charlotte Davies, Carmel Conefrey, Nicola Mills, Patricia Fairbrother, Chris Holcombe, Lisa Whisker, Joanna Skillman, Paul White, Douglas MacMillan, Charles Comins, William Hollingworth, Shelley Potter. 'A sledgehammer to crack a nut' or 'the safer option'? Understanding decision making for and against oncoplastic breast conserving surgery as an alternative to mastectomy in women with early breast cancer: The UK ANTHEM study abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-22-11.