Selective use of post-lumpectomy mammography after breast-conserving surgery

Objectives:Post-lumpectomy mammography (PLM) may detect suspicious residual calcifications after breast-conserving surgery (BCS).However, PLM may lead to patient anxiety, delays in initiating adjuvant treatment, and increased costs.We aimed to identify predictors of suspicious residual calcifications that may be used to select patients for whom PLM may be avoided. Methods:We conducted a retrospective analysis of patients with non-metastatic breast cancer who underwent BCS and PLM between May 2016 to June 2023 at a single institution.We recorded patient characteristics, the presence of suspicious calcifications on pre-operative mammography and PLM, pathology from initial biopsy and lumpectomy specimen, and whether additional biopsy, re-excision, or mastectomy was performed.Wilcoxon Ranked-Sum and Fisher's Exact tests were used to compare outcomes between cohorts.Univariate (UVA) and multivariable analyses (MVA) identified potential predictors of suspicious residual calcifications on PLM and the need for an additional procedure following PLM. Results:Among 463 patients with pure DCIS (56%), invasive ductal carcinoma (39.5%), or invasive lobular carcinoma (4.5%), 76 (16.4%) had suspicious residual calcifications on PLM, of whom 70 (41.7%)underwent an additional procedure, of which 43 (61.4%) had positive pathology.On MVA, clinical tumor size was a significant predictor of residual calcifications on PLM (odds ratio [OR], 2.38, p=0.008) and residual calcifications on PLM strongly predicted the likelihood of an additional procedure (odds ratio [OR], 64.9, p<0.001). Conclusion:Our findings suggest that patients with clinically small tumors and clear margins may represent a low-risk group in whom routine PLM could potentially be avoided.