Are Prognostic Factors the Same for Non-Invasive and Invasive Local Recurrence (LR) in Patients with Ductal Carcinoma In Situ (DCIS) Treated with Breast-Conserving Therapy (BCT)?
Laura Collins, Ninah Achacoso, Reina Haque, Larissa Nekhlyudov, Suzanne Fletcher, Charles Quesenberry, Stuart Schnitt, Laurel Habel. Beth Israel Deaconess Medical Center, Boston; Kaiser Permanente, California; Harvard Pilgrim Health Care Institute, Boston
Background: Several patient, pathologic and treatment factors have been reported to be associated with an increased risk of LR in patients with DCIS treated by BCT. Approximately half of such LR are non-invasive (DCIS) and half are invasive carcinomas. There is a perception that pathologic risk factors for non-invasive and invasive LR are the same, but few prior studies have addressed this issue.
Design: We conducted a case-control study of patients with DCIS treated with BCT at 3 integrated health plans to assess risk factors for LR. Slides of the index DCIS were reviewed from 225 patients who developed a LR (cases) and 394 patients without a LR (controls; matched to cases on age, diagnosis year, health plan, time since diagnosis). Conditional logistic regression was used to estimate the relative risk (RR) of LR associated with pathologic factors, controlling for confounding variables.
Results: Overall, the only pathologic features independently associated with an increased risk of LR were larger lesion extent and close/positive excision margins. However, when stratified by type of LR, these features were found to be significantly associated with non-invasive but not with invasive LR. The relationship between DCIS extent and type of LR is shown in the Table.
|Extent (#low power fields)||RR and 95% CI for Non-invasive LR||RR and 95% CI for Invasive LR|