E08. Highlights in benign and pre-invasive breast disease

Wire-guided lumpectomy of benign lesions has become a rare procedure after triple assessment using palpation, imaging and core biopsy. Current indications focus on pathologically proven B3 lesions, and on discrepancies between imaging results and core histology. A multimodality imaging approach and interpretation of imaging results according to the ACR-BI-RADS® breast imaging lexicon warrants characterisation of benign lesions with high negative predictive values. Digital mammography and advanced breast ultrasound − including flow and elasticity assessment − are the basic methods for detecting small recurrences and benign tissue reactions after breast-conserving therapy (BCT). High-risk patients represent the classic candidates for prophylactic mastectomy following informed consent. In addition to mammography, other methods − such as high-frequency ultrasound, contrast-enhanced magnetic resonance imaging (MRI), digital breast tomosynthesis − are candidates for an optimised preoperative staging of ductal carcinoma in situ (DCIS). Selective oestrogenreceptor (ER) modulators and aromatase inhibitors reduce women’s relative risk for developing ER-positive breast cancer by up to 50%. Negative surgical margins should be obtained for DCIS after BCS, regardless of radiation, and are associated with a decrease in ipsilateral tumour recurrences. Distance to clear margins >10mm is the best option. State of the art of breast surgery in benign breast disease Lumpectomy of benign lesions has become a rare procedure following a primary triple approach using palpation, imaging and core biopsy. Fast-growing benign solid tumours often present with a lump. The indication for excision biopsy of a possibly benign lesion covers: (a) histological lesions with an increased risk of developing subsequent breast cancer (B3 lesions); (b) exclusion of cancer by discrepancies between clinical findings, imaging results and core pathology; and (c) cosmetic and psychological reasons. Vacuum-assisted biopsy may be used as alternative to surgical wire-guided excision in patients with a limited extent of risk lesions [1]. Clinical imaging of benign breast disease State-of-the-art breast imaging and correlation with clinical findings characterises benign lesions or lumps with high negative predictive values [2]. The most common reasons for false-positive diagnoses are confusion between aberrations in the normal development and involution of the breast and tumours, and insufficient use of the ACR-BI-RADS® breast-imaging lexicon, in particular an incorrect appreciation of special cases. Stability over time, multiple round, bilateral lesions and typical benign calcifications or absent MR enhancement argue for benignity. Benign-looking lesions in high-risk candidates are suitable for biopsy when there are no typical cyst or fat necrosis findings [3]. State-of-the-art imaging of benign tissue reaction following BCT Typical benign tissue reactions encompass: (a) exudative and reparative tissue changes at the excision site; (b) diffuse breast oedema and fibrosis induced by radiation therapy; and (c) postoperative complications of flaps or implants. Digital mammography and advanced ultrasound (including flow and elasticity assessment) are the standard methods of surveillance and depict fat necrosis in up to 10% of patients, lymph cysts in 4%, nodular granuloma in 3%, recurrence in 0.5−1.5% per year of surveillance. MRI is the most sensitive imaging tool (95%) and ultrasound (US) is the most specific tool (96%) after BCT [4]. 0959-8049/$ – see front matter © 2014 ECCO − the European CanCer Organisation. All rights reserved. S16 Extended Abstracts Prophylactic mastectomy: when does this make sense? Patients with known high-risk factors such as genetic mutations or strong family history represent the classic candidates for prophylactic mastectomy. However, studies have shown that an increasing number of other women are choosing to have prophylactic mastectomy. In some patients the decision is not at all straightforward, and it is important to work through the pros and cons as well as the risks versus the benefits in each particular case so that patients will not regret their decision after informed consent has been given. If patients choose to have mastectomy in the prophylactic setting, immediate breast reconstruction should be explored in order to try and decrease the dramatic changes to the patients’ body image, lifestyle and sexuality [5]. New insights in DCIS imaging To date DCIS comprises approximately 20% of all mammographically detected breast malignancies. In contrast to a small proportion (17%) of “pure DCIS”, 83% of 512 histologically proven DCIS cases have been associated with invasive cancer after surgery at Osnabrueck Breast Centre. Use of high-frequency ultrasound, MRI or digital breast tomosynthesis can improve the accurate prediction of non-calcified disease extent. Imaging correlates the dilatation and unfolding of terminal duct lobular units (TDLUs) due to DCIS with descriptors such as a group of calcifications, pseudocystic mass or clumped enhancement. The extension of DCIS to multiple dilated ducts correlates with linear and linear branching imaging findings and segmental distribution. The underestimation rate of proven DCIS by 14-gauge automated core-needle biopsy is higher than that by 8or 11-gauge vacuumassisted biopsy (LCNB 47.8% versus VAB 16.1%) [6]. Chemoprophylaxis and systemic treatment of pre-invasive lesions High endogenous oestrogen levels and lifetime exposure have been recognised as important risk factors for promoting breast cancer. Selective oestrogen receptor modulators or aromatase inhibitors target oestrogen receptors, preventing oestrogen-responsive breast cancers. Tamoxifen and raloxifene are approved for women at “high risk” (characterised by a >1.66% risk of developing invasive breast cancer within the next 5 years). Both drugs reduce the risk of developing invasive breast cancer by up to 50%, and exemestane by 65%, compared to placebo. Adjuvant tamoxifen in DCIS with ER-positive foci decreases the risk of local recurrences. Current research is focusing on chemoprophylaxis for critical molecular pathways in ER-negative breast cancer [7]. Highlights in surgical treatment of DCIS For women with localised DCIS the treatment of choice is breast-conserving surgery using segmental excision alone or in combination with radiation. Four prospective randomised studies have shown that radiation therapy decreases ipsilateral breast tumour recurrence (IBTR) by approximately 50−60%. Tamoxifen added to radiation is effective in reducing IBTR for ER-positive patients only. Tamoxifen added to excision alone is ineffective for intermediate and high DCIS. Breast-conserving surgery should achieve clear margins >10mm. The low incidence of axillary metastasis in DCIS does not justify the routine use of sentinel-node biopsy in DCIS. Its use should be limited to patients undergoing mastectomy. New risk-predicting multi-parametric nomogram and gene expression assay (Oncotype DX DCIS Score) promise individualised treatment for women with DCIS who meet the ECOG (Eastern Cooperative Oncology Group) E5914 criteria [8].