A nationwide pathology study on surgical margins and excision volumes after breast-conserving surgery: There is still much to be gained

• Close combined with tumour-involved margins were reported in 33.8% of cases.
• One third of 9276 patients had eccentrically located tumours in the lumpectomy specimen.
• Tumour-free margins are achieved at the expense of healthy breast tissue resection.
• Quality indicators on margin involvement in BCS result in more mastectomies.

Aim of the studyThe current study aims to assess margin status in relation to amount of healthy breast tissue resected in breast-conserving surgery (BCS) on a nationwide scale.MethodsUsing PALGA (a nationwide network and registry of histology and cytopathology in the Netherlands), all patients who underwent BCS for primary invasive carcinoma in 2012–13 were selected (10,058 excerpts). 9276 pathology excerpts were analyzed for a range of criteria including oncological margin status and distance to closest margin, specimen weight/volume, greatest tumor diameter, and with or without localization method. Calculated resection ratios (CRR) were assessed to determine excess healthy breast tissue resection.ResultsMargins for invasive carcinoma and in situ carcinoma combined were tumor-involved in 498 (5.4%) and focally involved in 1021 cases (11.0%) of cases. Unsatisfactory resections including (focally) involved margins and margins ≤ 1 mm were reported in 33.8% of patients. The median lumpectomy volume was 46 cc (range 1–807 cc; SD 49.18) and median CRR 2.32 (range 0.10–104.17; SD 3.23), indicating the excision of 2.3 the optimal resection volume.ConclusionThe unacceptable rate of tumor-involved margins as well as margins ≤ 1 mm in one third of all patients is also achieved at the expense of healthy breast tissue resection, which may carry the drawback of high rates of cosmetic failure. These data clearly suggest the need for improvement in current breast conserving surgical procedures to decrease tumor-involved margin rates while reducing the amount of healthy breast tissue resected.