INTRODUCTIONBreast surgery is a core component of general surgery; however, previous studies have shown that general surgery residents (GSRs) are performing fewer operations in this area. This study analyzes the 20-y trends in GSR breast surgery experience.METHODSCase numbers were extracted from the Accreditation Council for Graduate Medical Education database from 2003 to 2023. Breast cases were categorized by sentinel lymph node biopsy, excisional biopsy (EB), simple mastectomy (SM), modified radical mastectomy, and radical mastectomy. Yearly average case numbers for total general and breast surgery cases were calculated. Surgical resident role (chief versus junior residents) was evaluated. Linear regression analyzed time trends.RESULTSFrom 2003 to 2023, GSRs reported a 15% increase in average total cases performed (P < 0.001), although there was a nonsignificant 8.1% decrease in total breast cases performed. Juniors performed 56.9-61.6 operations/year, where chiefs performed 9.2-10.3 breast operations/year. The annual number of chief-performed sentinel lymph node biopsies (1.8-0.8, P < 0.001) and modified radical mastectomies (2.0-0.4 cases, P < 0.001) decreased significantly over this time period, as did the number performed by juniors (4.0-3.7 cases [P < 0.001] and 8.1-2.8 cases [P < 0.001], respectively). Conversely, the number of chief-performed EBs (1.8-4.1 cases, P < 0.001) and SMs (1.7-1.9 cases, P = 0.012), and junior-performed EBs (8.7-24.3, P < 0.001) and SMs (7.1-9.4 cases, P < 0.001), significantly increased during this time.CONCLUSIONSAlthough the number of breast surgeries performed by GSRs has not changed significantly, case mixes have shifted. Guideline changes are impacting the case composition for trainees and may affect comfort in practice, as opportunities to perform certain cases continue to decrease.