[131] 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 LRRR and 95% CI for Invasive LR
11.0Ref1.0Ref
2-52.40.9-6.51.00.3-3.1
6-93.51.1-11.01.10.3-3.8
10-145.31.8-16.20.70.2-2.6
15-196.71.9-23.41.20.2-5.9
>203.91.2-12.21.60.4-5.4


Both close and positive margins were associated with a significant increase in the risk of non-invasive LR (RR=2.2 and RR=5.3; 95%CI 1.1-4.3 and 2.1-13.4 respectively), but not with invasive LR (RR=1.9 and 1.7; 95%CI 0.9-4.2 and 0.6-4.9 respectively). No other pathologic features studied (e.g. nuclear grade, architectural pattern, comedo necrosis) were associated with either type of LR.
Conclusions: We found prognostic factors for non-invasive and invasive LR following BCT for DCIS differed. Tumor burden (extent and margin status) was associated with non-invasive but not invasive LR. Features of DCIS specifically associated with invasive LR were not identified. These results raise the possibility that investigating other factors, such as the microenvironment, may be of value for identifying risk factors for invasive LR.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 45, Monday Afternoon

 

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