Differences between screen-detected and interval breast cancers among BRCA mutation carriers

Abstract

Background: BRCA mutation carriers have an elevated lifetime breast cancer risk and remain at risk for interval cancer development. We sought to compare BRCA mutation carriers with screen-detected versus interval breast cancers. Methods: Women with a known BRCA mutation prior to a breast cancer diagnosis were identified. Clinical and pathologic factors, and imaging within 18 months of diagnosis were compared among screen-detected versus interval cancers. Interval cancers were those detected by physical exam among women undergoing regular screening. Results: Of 124 breast cancers, 92 were screen and 22 clinically detected, of which 11 were interval cancers among regular screeners, and 10 were incidentally found on prophylactic mastectomy. Women with interval cancers were younger, had lower body mass indexes, and were more likely to be Black than those with screen-detected cancers (p < 0.05). Interval cancers were all invasive, larger, more likely to be node positive, and more likely to require axillary lymph node dissection and chemotherapy (p < 0.05). No significant differences were seen by BRCA mutation, mammographic density, MRI background parenchymal enhancement, tumor grade, or receptor status between cohorts. Women screened with both mammogram and MRI had significantly lower proportions of interval cancers compared to women screened with only mammogram or MRI alone (p < 0.05). Conclusions: Interval breast cancers among BRCA mutation carriers have worse clinicopathologic features than screen-detected tumors, and require more-aggressive medical and surgical therapy. Imaging with mammogram and MRI is associated with lower interval cancer development and should be utilized among this high-risk population.