Breast conservation in ductal carcinoma in situ (DCIS): what defines optimal margins?

Abstract

The introduction of mammographic screening has resulted in a rise in the detection rate of ductal carcinoma in situ (DCIS), currently accounting for one-fifth of screen-detected breast cancers. Although 60-70% of DCIS are treated with breast-conserving surgery (BCS) with or without radiotherapy, the frequency of subsequent surgery to re-excise positive margins in order to reduce the probability of recurrences remains high. DCIS recurrence is associated not only with financial, health and psychological implications; approximately half these recurrences are invasive disease. An appropriate margin width for patients undergoing BCS for invasive breast cancer has been largely agreed. Although there is a perception that such recommendations may be applicable to DCIS, major differences exist which may affect this application. Importantly, DCIS patients often do not receive systemic adjuvant (endocrine) therapy and not all receive radiotherapy in routine practice. There is evidence that wide margins (i.e. >10 mm) confer better protection against recurrence than positive (i.e. 0 mm) margins; however, there remains a debate concerning the optimum margin width between 0 and 10 mm. Previous studies have demonstrated that radiation therapy may not compensate for lack of re-excision in those patients with positive or close margins, while wide margins will inevitably compromise cosmesis and patients' body image perception. This review aims to address the clinical question of the minimal margin width in DCIS treated with BCS that is associated with the lowest recurrence rate and when, therefore, further surgical intervention for re-excision can be safely avoided. A range of clinical circumstances that might affect this are considered.

Surgical management of ductal carcinoma in situ of the breast: A large retrospective study from a single institution

“…Resection margin status data were further categorized based on the recent recommendations; that is, positive margin (tumor on ink), close margin (<2 mm), and negative margin (≥2 mm) . For comparison purposes, the whole cohort was further split into two groups: those diagnosed between 1987‐2008 (n = 803) and 2009‐2017 (n = 446).…”

“…Such a finding perhaps illustrates the controversy in pathological evaluation. 24 Presence of residual DCIS was correlated to other adverse clinicopathological parameters that is symptomatic presentation, larger tumor size, DCIS with cribriform and micropapillary morphology. Previous studies were performed to establish a margin index based on tumor size and the closest surgical margin to show its association with presence of residual tumor tissue after re-excision, but this did not show significant association.…”

“…In this study, half of the re‐excised specimens were free of residual tumor, even though some cases were reported to have tumor on ink after the primary excision. Such a finding perhaps illustrates the controversy in pathological evaluation . Presence of residual DCIS was correlated to other adverse clinicopathological parameters that is symptomatic presentation, larger tumor size, DCIS with cribriform and micropapillary morphology.…”

“…Resection margin status data were further categorized based on the recent recommendations; that is, positive margin (tumor on ink), close margin (<2 mm), and negative margin (≥2 mm). 20,24 For comparison purposes, the whole cohort was further split into two groups: those diagnosed between 1987-2008 (n = 803) and 2009-2017 (n = 446). This was based on the guideline change with regard to margin of excision, soon after 2008, with acceptable free margin after BCS in DCIS of 5 mm instead of 10 mm free margin.…”

Polygon method: A systematic margin assessment for breast conservation

“…First, in the conventional approach, breast excision margins are evaluated on sections cut perpendicular to the outer surface of the specimen after painting the surface with insoluble dye. 18,27,28 A major limitation of this approach is its ineffectiveness in determining whether the entire DCIS is completely removed because DCIS spreads insidiously along the three-dimensional mammary duct lobular system, resembling the root of plant 29 ; whereas the inked margin only reveals a two-dimensional cross-section of the system. Therefore, a mere negative finding by the conventional method (inked margin) does not exclude the remaining DCIS in the preserved breast.…”