[176] Outcome of Women with Ductal Carcinoma In Situ (DCIS) and Concurrent Lobular Neoplasia Treated with Breast Conserving Therapy: A Case-Control Study of 657 Patients from the Cancer Research Network

LC Collins, SJ Schnitt, N Achacoso, R Haque, L Nekhlyudov, S Fletcher, C Quesenberry, L Habel. Beth Israel Deaconess Medical Center, Boston; Kaiser Permanente Northern California, San Francisco; Kaiser Permanente Southern California, Los Angeles; Harvard Pilgrim Health Care, Boston

Background: A variety of clinical and pathologic factors influence the local recurrence (LR) rate among women with DCIS treated with breast conserving therapy (BCT). However, the impact of concurrent lobular neoplasia (LN) on the risk of LR in women with DCIS treated with BCT has not been examined in detail.
Design: Among 2,995 women with DCIS treated with BCT between 1990-2001 at three HMOs in the Cancer Research Network, 657 were enrolled in a case-control study to assess clinical and pathologic factors associated with LR and had slides available for review. We examined the association between the presence of LN in these specimens and various clinical factors (age at diagnosis, presentation, family history), pathologic features of the DCIS (nuclear grade, architectural pattern, comedo necrosis, cancerization of lobules, stromal desmoplasia/inflammation), and the presence of concurrent atypical ductal hyperplasia and columnar cell lesions. We also examined the influence of LN on the risk of LR in these patients. Relative risks were adjusted for matching factors, treatment, lesion size and margin status.
Results: Specimens from 169 of the 657 women with DCIS (26%) additionally demonstrated LN. The presence of LN was not associated with patient age, presentation, or family history of breast cancer. None of the pathologic features of DCIS were significantly associated with the presence of LN. However, LN was significantly associated with the concurrent presence of flat epithelial atypia (p<0.001) and atypical ductal hyperplasia (p=0.001). Overall, women with DCIS and concurrent LN had a 1.9-fold increase in their risk of local recurrence (95% CI 1.2-2.9) when compared with women without concurrent LN. When stratified by type of local recurrence, LN was significantly associated with DCIS recurrence (RR 2.3, 95% CI 1.2-4.2) but not with invasive recurrence (RR 1.3, 95% CI 0.7-2.6).
Conclusions: Among this population of women with DCIS treated with BCT, the presence of LN was significantly associated with the presence of other low grade precursor lesions. Moreover, the presence of concurrent LN conferred a greater than 2-fold increase in the risk of local recurrence of DCIS.
Category: Breast

Monday, March 22, 2010 11:45 AM

Platform Session: Section C, Monday Morning


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