BackgroundDespite similar survival rates, breast‐conserving therapy (BCT) remains a distant second choice after simple mastectomy for patients with early‐stage breast cancer in Singapore. Uptake of reconstruction after mastectomy is also low (18 per cent). The aim of this study was to explore the factors influencing a patient's choice for mastectomy when eligible for BCT, and why patients decline reconstruction after mastectomy.MethodsPatients from the National Cancer Centre Singapore, who were eligible for BCT but chose mastectomy without reconstruction, between December 2014 and December 2015 were included. An interviewer‐administered questionnaire focusing on patients' reasons for choosing mastectomy over BCT and not opting for immediate breast reconstruction after mastectomy was used. Tumour characteristics were retrieved from medical records. Spearman's rank correlation coefficient, Mann–Whitney U and Kruskal–Wallis tests were used to analyse the correlation between the patient's self‐rated influential factors and variables. Statistical significance was taken as P < 0·050.ResultsNinety‐one patients were included (90·1 per cent response rate). The main reasons for choosing mastectomy over BCT were: fear of cancer recurrence (considered very important in 74 per cent), the perception that health outweighs breast retention (49 per cent) and the possibility of second surgery for margins (40 per cent). Key factors for rejecting immediate reconstruction after mastectomy were: patient‐perceived ‘old age’ (very important in 53 per cent), concern about two sites of surgery (42 per cent) and financial cost (29 per cent). Given a second chance, 19·8 per cent of patients would undergo BCT instead of mastectomy.ConclusionThis study has identified the considerations that women in Singapore have when deciding on breast cancer surgery. Some perceptions need to be addressed for women to make a fully informed decision, especially as one‐fifth regret their initial choice.