Background: Since concurrent malignancy may be associated with radial scars (RS) in up to 45% of RS diagnosed on core biopsy, surgical excision is usually advised. Recent very low upgrade rates have caused a re-evaluation of the need for routine surgery. We aimed to find subsets of RS at such low risk of upgrade, as to render imaging surveillance a plausible alternative to surgery.
Design: We performed a systematic review of the Pubmed, Cochrane and Embase databases, focusing on the following eligibility criteria: full papers, published after 1998, in English, included at least 5 RS, provided information on needle biopsy gauge and upgrade rates based on the excised lesion. For the meta-analysis, studies were grouped by the presence of histologic atypia and the core needle gauge. Study-specific and pooled upgrade rates were calculated for each subgroup.
Results: 49 studies that included 3163 RS with surgical outcomes are included. There were 217 upgrades to malignancies, 71 (32.7%) invasive and 144 (66.4%) DCIS. The random-effects pooled estimate was 7% (95% CI 5, 9%). Among the pre-planned subgroups, in RS assessed by 14G NCB the upgrade rates were: without atypia - 5% (95% CI 3, 8%), mixed or presence of atypia not specified - 15% (95% CI 10, 20%), with atypia - 29% (95% CI 20, 38%). For RS assessed by a mix of 8-16G cores the respective upgrade rates were 2% (95% CI 1, 4%), 12% (95% CI 6, 18%) and 11% (95% CI 3, 23%) and for RS assessed by 8-11 vacuum assisted biopsies 1% (95% CI 0, 4%), 5% (95% CI 0, 11%) and 18% for the one study of RS with atypia assessed by VAB. Surgery after VAB excision showed no upgrades. The difference across all subgroups was statistically significant.
Conclusion: When stratified by atypia and biopsy gauge, upgrade rates in RS are consistent and predictable. RS assessed by VABs and lacking atypia have a 1% (95% CI 0, 4%) upgrade rate to DCIS. Other groups have upgrade rates of 2-28%. This risk may be reduced by VAB excision. The results of this meta-analysis provide a decision aid and evidence-based selection criteria for surgery after a needle biopsy diagnosis of RS.
Keywords: Breast cancer; Core biopsy; Mammography; Radial scar; Screening.