The study aimed to assess the effects of breast-conserving surgery (BCS) versus mastectomy on survival and quality of life in Stages I, II, and III breast cancer, providing solid evidence for clinical decisions. We conducted a meta-analysis of randomized controlled trials on breast cancer treatments, searching databases such as PubMed and the Cochrane Library to compare BCS, and mastectomy's effects on survival and quality of life. A combined total of 16 734 patients in the control group and 17 435 patients in the experimental group were included in this analysis. This meta-analysis used RevMan 5.3 (Cochrane Collaboration, Copenhagen, Denmark) software for analysis. Our meta-analysis of 34 169 patients from 11 studies showed that BCS significantly reduced the overall recurrence rate at a median follow-up of 29 months, with a mean difference of 1.27 and a 95% confidence interval of 1.19-1.36, strongly supporting its effectiveness (P < .00001). Furthermore, our analysis found no significant increase in 5-year local recurrence rates for BCS versus mastectomy, indicating its long-term effectiveness with a mean difference of 1.13 (95% confidence interval: [1.03, 1.24], P = .01). Additionally, there was a notable decrease in tissue ischaemic necrosis among patients who had received BCS, with a mean difference of 0.37 (95% confidence interval: [0.33, 0.42], P < .00001), underscoring its benefits and long-term viability. BCS resulted in fewer cases of tissue ischaemic necrosis and higher body image scores compared with mastectomy, suggesting that it is a preferable option for better cosmetic outcomes and potentially favourable effects on prognosis and quality of life.