title: A population-based validation study of the DCIS Score predicting recurrence risk in individuals treated by breast-conserving surgery alone.
abstract: Validated biomarkers are needed to improve risk assessment and treatment decision-making for women with ductal carcinoma in situ (DCIS) of the breast. The Oncotype DX DCIS Score (DS) was shown to predict the risk of local recurrence (LR) in individuals with low-risk DCIS treated by breast-conserving surgery (BCS) alone. Our objective was to confirm these results in a larger population-based cohort of individuals. We used an established population-based cohort of individuals diagnosed with DCIS treated with BCS alone from 1994 to 2003 with validation of treatment and outcomes. Central pathology assessment excluded cases with invasive cancer, DCIS < 2 mm or positive margins. Cox model was used to determine the relationship between independent covariates, the DS (hazard ratio (HR)/50 Cp units (U)) and LR. Tumor blocks were collected for 828 patients. Final evaluable population includes 718 cases, of whom 571 had negative margins. Median follow-up was 9.6 years. 100 cases developed LR following BCS alone (DCIS, N = 44; invasive, N = 57). In the primary pre-specified analysis, the DS was associated with any LR (DCIS or invasive) in ER+ patients (HR 2.26; P < 0.001) and in all patients regardless of ER status (HR 2.15; P < 0.001). DCIS Score provided independent information on LR risk beyond clinical and pathologic variables including size, age, grade, necrosis, multifocality, and subtype (adjusted HR 1.68; P = 0.02). DCIS was associated with invasive LR (HR 1.78; P = 0.04) and DCIS LR (HR 2.43; P = 0.005). The DCIS Score independently predicts and quantifies individualized recurrence risk in a population of patients with pure DCIS treated by BCS alone.
authors.affiliation: Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, eileen.rakovitch@sunnybrook.ca.
authors.forename: Eileen
authors.initials: E
authors.lastname: Rakovitch
authors.forename: Sharon
authors.initials: S
authors.lastname: Nofech-Mozes
authors.forename: Wedad
authors.initials: W
authors.lastname: Hanna
authors.forename: Frederick L
authors.initials: FL
authors.lastname: Baehner
authors.forename: Refik
authors.initials: R
authors.lastname: Saskin
authors.forename: Steven M
authors.initials: SM
authors.lastname: Butler
authors.forename: Alan
authors.initials: A
authors.lastname: Tuck
authors.forename: Sandip
authors.initials: S
authors.lastname: Sengupta
authors.forename: Leela
authors.initials: L
authors.lastname: Elavathil
authors.forename: Prashant A
authors.initials: PA
authors.lastname: Jani
authors.forename: Michel
authors.initials: M
authors.lastname: Bonin
authors.forename: Martin C
authors.initials: MC
authors.lastname: Chang
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Robertson
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Slodkowska
authors.forename: Cindy
authors.initials: C
authors.lastname: Fong
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Anderson
authors.forename: Farid
authors.initials: F
authors.lastname: Jamshidian
authors.forename: Dave P
authors.initials: DP
authors.lastname: Miller
authors.forename: Diana B
authors.initials: DB
authors.lastname: Cherbavaz
authors.forename: Steven
authors.initials: S
authors.lastname: Shak
authors.forename: Lawrence
authors.initials: L
authors.lastname: Paszat
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009864:Ontario / Q000453:epidemiology; D011159:Population Surveillance; D018570:Risk Assessment