{"entity":{"id":"dcis","kind":"term","name":"Ductal carcinoma in situ (DCIS)","aka":["DCIS","ductal carcinoma in situ","ductal in situ"],"tldr":"Breast cancer cells confined inside the milk ducts, found mostly by mammography as calcifications. It is not life-threatening in itself, but around a third would progress to invasive cancer if left.","summary":"DCIS makes up 20-25% of screen-detected breast cancers. Standard treatment is lumpectomy with radiotherapy (or mastectomy for extensive disease) plus tamoxifen or an aromatase inhibitor if ER-positive; low-dose tamoxifen (5 mg, TAM-01) halves recurrence with fewer side effects. Because many DCIS lesions are indolent, active surveillance trials (COMET, LORIS, LORD) tested omitting surgery for low-risk disease, and COMET found no excess invasive cancer at 2 years. It is a leading example of the overdiagnosis debate in screening.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Ductal_carcinoma_in_situ","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Ductal_carcinoma_in_situ"}],"tags":[],"related":["carcinoma-in-situ","lumpectomy","active-surveillance"],"cancers":["breast-hr-positive"],"sections":["early-detection"],"technologies":[],"targets":[],"drugs":["tamoxifen"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Pathology"},"route":"/terms/dcis/","neighbours":{"term":[{"id":"active-surveillance-term","kind":"term","name":"Active surveillance and observation","route":"/terms/active-surveillance-term/"},{"id":"carcinoma-in-situ","kind":"term","name":"Carcinoma in situ (CIS)","route":"/terms/carcinoma-in-situ/"},{"id":"lumpectomy","kind":"term","name":"Lumpectomy (breast-conserving surgery)","route":"/terms/lumpectomy/"}],"technology":[{"id":"active-surveillance","kind":"technology","name":"Active surveillance","route":"/technologies/active-surveillance/"},{"id":"breast-mri-coils-abbreviated-mri","kind":"technology","name":"Breast MRI coils and abbreviated breast MRI","route":"/technologies/breast-mri-coils-abbreviated-mri/"},{"id":"contrast-enhanced-mammography","kind":"technology","name":"Contrast-enhanced mammography","route":"/technologies/contrast-enhanced-mammography/"}],"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"ductal-carcinoma-in-situ","kind":"cancer","name":"Ductal carcinoma in situ (DCIS)","route":"/cancers/ductal-carcinoma-in-situ/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"}],"section":[{"id":"early-detection","kind":"section","name":"Early Detection & Screening","route":"/fronts/early-detection/"}],"drug":[{"id":"tamoxifen","kind":"drug","name":"Tamoxifen","route":"/drugs/tamoxifen/"}]}}