BACKGROUND: To elucidate the cause of in-breast recurrence after
breast conserving surgery, we analyzed the characteristics of resected specimens histopathologically, especially the
surgical margin status. MATERIALS AND METHODS: 1) Pathological
surgical margin positivity was reevaluated in terms of the distance from the resected
surgical margin by pathologists from seven institutions in 486 cases with complete stepwise pathological examination. 2) We reviewed pathological specimens including
surgical margins from 30 patients with in-breast recurrence for whom serial sections of resected primary
breast cancer specimens were available and made comparisons of the time to in-breast recurrence. RESULTS:
Cancer cells at the
surgical margin were present at a rate of 4.1% on the surface and 15.2% within 5 mm on the areolar side of the
surgical margin. Histopathologically, the reasons for local recurrence after breast conserving
therapy included a
positive surgical margin (21/30), lymphatic permeation (4/30), and others (5/30). The last category included cases with an inadequate margin diagnosis because of a biopsy
scar. Disease-free intervals for the patients without postoperative
radiotherapy decreased as the volume of
cancer cell nests in thesurgical margin increased (P=0.06). On the other hand, this trend was not observed in the group with postoperative
radiotherapy. CONCLUSION: Adequate materials are essential for accurate evaluation of
surgical margin status. Quantitative evaluation of
surgical margin status, apart fromwhether or not
radiotherapy was performed, is important for estimating the riskand disease-free period to in-breast recurrence.