Background Positive margins after breast-conserving surgery (BCS) and subsequent second surgery are associated with increased costs and patient discomfort. The aim of this study was to develop a prediction model for positive margins based on risk factors available before surgery. Methods Patients undergoing BCS for in situ or invasive cancer between 2015 and 2016 at site A formed a development cohort; those operated during 2017 in site A and B formed two validation cohorts. MRI was not used routinely. Preoperative radiographic and tumour characteristics and method of operation were collected from patient charts. Multivariable logistic regression was used to develop a prediction model for positive margins including variables with discriminatory capacity identified in a univariable model. The discrimination and calibration of the prediction model was assessed in the validation cohorts, and a nomogram developed. Results There were 432 patients in the development cohort, and 190 and 157 in site A and B validation cohorts respectively. Positive margins were identified in 77 patients (17.8 per cent) in the development cohort. A non-linear transformation of mammographic tumour size and six variables (visible on mammography, ductal carcinoma in situ , lobular invasive cancer, distance from nipple–areola complex, calcification, and type of surgery) were included in the final prediction model, which had an area under the curve of 0.80 (95 per cent c.i. 0.75 to 0.85). The discrimination and calibration of the prediction model was assessed in the validation cohorts, and a nomogram developed. Conclusion The prediction model showed good ability to predict positive margins after BCS and might, after further validation, be used before surgery in centres without the routine use of preoperative MRI. Presented in part to the San Antonio Breast Cancer Symposium, San Antonio, Texas, USA, December 2018 and the Swedish Surgical Society Annual Meeting, Helsingborg, Sweden, August 2018.

Background Breast-reduction techniques are increasingly used in oncoplastic breast surgery. Bilateral therapeutic mammoplasty has the benefit of decreasing breast volume, enabling resection of larger tumors, and the potential to assure good postoperative symmetry. The aims of this study were to objectively asses the cosmetic outcomes of therapeutic mammoplasty in patients with breast cancer, using the breast cancer conservative treatment cosmetic results (BCCT.core) software, to compare this score with the surgeon’s score and the patient’s assessment, and to evaluate if other defined parameters have an impact on cosmetic outcomes. The secondary aim was to compare breast symmetry pre- and postoperatively. Materials and Methods We enrolled 146 consecutive patients with primary breast cancer who underwent therapeutic mammoplasty between 2011 and 2018 in Kristianstad Central Hospital, Sweden. We retrospectively collected data from patients’ records. We analyzed the BCCT.core score using postoperative photographs to objectively evaluate cosmetic outcomes on a four-grade scale and compared with preoperative photographs to evaluate symmetry. Cosmetic outcomes were also assessed subjectively by patients and surgeons, using a 10-point Likert scale. Results The majority of patients (89%) had good or excellent BCCT.core scores, which correlated with surgeons’ scores, rs =  − 0.22 (p < 0.001). Overall, patients were more satisfied with the cosmetic outcomes than the surgeons (p < 0.001). Evidence supporting an association between the defined clinicopathological variables, for example, tumor size, and cosmetic outcomes, was weak. Conclusion Therapeutic mammoplasty yields a very good cosmetic outcome, evaluated both by subjective and objective measurements. Importantly, symmetry can be improved in patients with asymmetry.

Background: Neoadjuvant chemotherapy (NAC) is an established treatment option in early breast cancer. NAC potentially downstages the tumor and, combined with oncoplastic techniques, may increase the eligibility for breast conserving surgery (BCS). NAC can also result in less surgical morbidity of the axilla if axillary clearance can be avoided. In addition, preoperative medical treatment allows for a thorough evaluation of treatment response and lays the foundation for adjuvant treatment decisions. The aim of the study was to prospectively estimate the proportion of BCS post NAC and the relation to well-defined factors associated with BCS post NAC. Materials and methods: This observational prospective cohort study included 226 patients in the SCAN-B neoadjuvant cohort (Clinical trials: NCT02306096) receiving NAC between 2014 and 2019. Eligibility for BCS was based on the assessment of the surgeon at time of diagnosis and again post NAC. All the covariables were defined at time of diagnosis from mammograms and core needle biopsies, except for pathological complete response (pCR). Treatment generally consisted of 6 to 7 three-weekly treatment cycles of anthracycline- and taxane-based chemotherapy, given in sequence. In HER2-positive disease, HER2-directed antibodies were added as appropriate.The primary aim was to estimate the proportion of BCS after NAC and the secondary aim was to evaluate factors as predictors of BCS, including gene expression and surrogate molecular subtypes (St. Gallen), breast density, and other putative modifying factors.Uni- and multivariable logistic regression analysis were performed including covariates of clinical relevance and/or associated with the outcome measures (BCS versus mastectomy). Results: The BCS rate increased during the study years, from 37% to 52%. pCR was achieved in 69 patients (30%). Predictors with a negative association to BCS were larger tumor size on mammography (T3 vs T1) (odds ratio (OR)=0.20, 95% confidence interval (CI) [0.06,0.64]), lack of visibility on ultrasound (OR=0.08, 95% CI [0.001,0.63]), lobular histological subtype vs other subtypes (OR=0,20, 95% CI [0.06,0.61)). Factors positively associated with BCS were benign axillary lymph node status (OR=2.26, 95% CI [1.26,4.06]) and surrogate molecular subtypes; patients with triple negative and HER-2 positive tumors had the highest probability of receiving BCS, 65% and 54%, respectively. Gene expression subtypes had a similar trend of being associated with BCS; patients with basal like and HER-2 enriched tumors had higher odds ratio for BCT than patients with luminal subtypes (Table 1). In the multivariable logistic regression analysis, tumor size on mammography and axillary status had the strongest association to BCS (OR=0.95, 95% CI [0.92,0.98] and OR=2.08, 95% CI [0.99,4.35], respectively). Conclusions: Our study shows that the rate of BCS after NAC increased over the study years, but mastectomy rate in the study was still close to 50%. With increasing number of patients achieving pCR after NAC, the BCS rate should be possible to increase further. Predictors of BCS after NAC were identified, and benign axillary lymph nodes and smaller tumor size defined at time of diagnosis were the strongest predictors of BCS, supporting that initial tumor stage was important for the choice of surgery after NAC. Table 1. Baseline characteristics and univariable logistic regression. 1. Determined by biopsy or sentinel node. 2. Only tumors visible on mammography. 3. Defined as ypT0/ypTis/ypN0. Citation Format: Kim Gulis, Julia Ellbrant, Pär-Ola Bendahl, Tor Svensjö, Johan Vallon-Christersson, Ida Dalene Skarping, Niklas Loman, Lisa Rydén. Save the breast after neoadjuvant therapy – identifying radiological and tumor related factors of importance for breast conserving surgery after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-09-06.

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