Abstract SP094: DCIS - Con

Ductal carcinoma in situ (DCIS) represents a collection of biologically heterogenous pre-invasive breast lesions some with the potential for progression to invasive cancer. Widespread adoption of screening mammography has increased the diagnosis of DCIS and may contribute to overdiagnosis identifying some conditions that may never impact one’s overall health. Unfortunately, clinicians treating DCIS patients currently lack robust biomarkers stratifying DCIS patients into those at high or low risk for invasive progression. Further, variations in pathologic assessment and grade, intra-lesional DCIS heterogeneity, and discordance in pathologic interpretations between pathologists make it challenging for providers to further identify appropriate low risk DCIS patients for active surveillance. Guideline concordant care including excision and potentially radiation and anti-estrogen therapies should remain as the standard of care and provides a definitive treatment endpoint which patients desire. Existing evidence documents a significant upstage rate of DCIS to invasive disease at surgical excision including a small, but important population benefiting from adjuvant systemic therapy. Finally, patient anxiety and documented poor adherence rates to endocrine therapy preclude active surveillance and after all the morbidity of surgical excision is low. Citation Format: S McLaughlin. DCIS - Con [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP094.