P4-18-05: Ductal Carcinoma In Situ with Microinvasion: Clinical and Pathological Characteristics, Treatments and Outcomes.

Abstract

Abstract Background: Ductal carcinoma in situ with microinvasion (DCISM) is a rising rare entity. Because of that and its controversial pathological definition, there is a lack of clear recommendations for treatment. The purpose of this study was to describe the clinical and pathological characteristics, treatments and outcomes of our single institutional experience. Patients and methods: Individual clinical and pathological data were collected from 63 women, diagnosed and treated for DCISM at the Claudius Regaud Cancer Hospital between January 2000 and April 2010. All available histological material (45 patients) was reviewed by an expert pathologist. Results: The median age was 56 years (range 34–83). Seven patients (11.5%) had a personal history of DCIS, 27 patients (42%) a familial history of breast cancer. Fourteen patients (22%) had a clinical sign at the diagnosis. Fifty one patients were mammographically detected (81%). All the patients underwent surgery, mastectomy for 17 patients (27.4%) and conservative surgery for 45 (72.6%). Secondary surgery of the breast was required for 21 patients (46.6%) after conservative surgery, enlarging surgery (N=13) or mastectomy (N=8). Surgical axillary lymph node evaluation was performed on 52 patients (82,5%), axillary dissection alone for 10 patients, sentinel node biopsy alone for 37 patients and the 2 methods for 5 patients. The median size of the DCIS was 16mm (6-80mm) with 37/60 (61.7%) grade III Van Nuys classification. The most histological subtype was comedo carcinoma (68%). Concerning the 45 reviewed biopsies, the size of the microinvasive component was ≤ 1mm for 38 lesions and between 1 and 2 mm for 7 lesions. Hormonal receptor status was positive for 29 (64.4%), 27 (64.3%) for estrogen receptors and 20 (44.4%) for progesterone receptors. HER 2 status was performed for 34 patients, among 12 (35%) of them were found overexpressed on the microinvasive component. Lymph node invasion was found among 2 of the 52 patients (3.8 %) who underwent axillary lymph node evaluation. Radiation therapy was delivered to all the patients after conservative surgery (n=37)(50 Gy with a 10 Gy boost for 22 of them) and 2 after mastectomy (chest wall irradiation (50 Gy)). Adjuvant hormonotherapy was delivered on 11 patients (18%). With a median follow-up of 36,4 months (95%CI=[27.7- 44.16]), 62 patients are alive at the last follow-up and 58/63 free of disease (2 relapses and 3 second cancers).The 3 year disease free survival rate was 91.1 (95%CI=[78.1;96.6] ). During follow-up, two local relapses occurred on patients treated by mastectomy. One of them had local invasive relapse at 43 months and she is still NED after 90 months. The second patient who had local invasive carcinoma with axillary node invasion at 32 months treated by conservative surgery, axillary dissection, radiotherapy and chemotherapy, had metastasis at 51 months and passed away after 70 months. Conclusion: Mammographic screening programmes increase the rate of small diagnosed tumours, specially DCISM. Despite a priori good prognostic outcome, 2 axillary node involvements and 2 delayed relapses were observed. So, this kind of presentation deserves better evaluation of relapse risk factors to determine adapted adjuvant therapies. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-18-05.