Abstract P2-01-26: Role of age, menopausal status and biological tumor characteristics on sentinel lymph node metastasis in early breast cancer patients with favorable prognostic features: A retrospective, mono institutional study on 345 cases
Authors: La Verde Nicla , Casiraghi Chiara , Dazzani Chiara , Floriani Irene , Biagioli Elena , Cordovana Andrea , Gerardi Chiara , Farina Gabriella , Croce Anna Maria , Bianchi Filippo , Lunghi Claudio , Lamera Mauro , Bonavita Marcello , Bernardin Elena , Gherardi Giorgio 
Published: May 2015

Background: Sentinel lymph node biopsy (SLNB) is recognized as a standard procedure for women with early breast cancer. Recently some studies reported the futility of axillary lymph node dissection in patients (pts) who are SLN positive but bear favorable clinical and primary tumor biological characteristics. Since we believe that the choice of a proper axillary treatment in early breast cancer could be personalized and axillary SLNB could be avoided in specific subgroups of pts, we designed this study to identify key primary tumor characteristics and pts' clinical features that could influence the indication to perform SLN biopsy.

Patients and methods: Retrospective analysis was carried out in women who had undergone surgery and SLNB for early breast cancer (pT1-2) from 2005 to 2013 at the Fatebenefratelli e Oftalmico Hospital in Milan, Italy. All SLNs were examined histologically in toto on seriated permanent sections. The association between SLN positivity and the following variables as age, menopausal status, tumor size, histological grading, presence of extensive "in situ" components and lymphovascular invasion (LVI), quantitative evaluation of Ki-67, HER2 expression, oestrogen and progesterone receptors, was assessed by means of univariate and multivariate logistic models.

Results: The records of 345 pts with early breast cancer who underwent surgery were retrieved. Mean age was 61 years and 79% pts were postmenopausal. 85% were treated with quadrantectomy and 66% had only one SLN removed. SLN metastasis was detected in 24% of cases. Tumor size was &lt;2 cm in 76% of pts, and 86% were of luminal subtypes. Peritumoral LVI was detected in 32% of cases. At univariate analysis a statistically significant association was found between tumor size [odds ratio (OR) 1.05, confidence interval at 95% (95%CI) 1.01-1.08; p=0.005], histological grade (OR 1.50, 95%CI 1.04-2.16; p=0.029), presence of LVI (OR 3.81, 95%CI 2.27-6.37; p &lt; .0001). At multivariate analysis only LVI confirmed to increase the risk of SLN positivity in the whole series (OR 3.26, 95%CI 1.89-5.64; p &lt; .0001) as well as in subgroup of pts with luminal A and B subtype (OR 3.51, 95%CI 1.92-6.44; p &lt; .0001). Negative and positive predictive values of LVI were 83.9% and 42.2%, respectively. Interestingly, in a pre-planned subgroup analysis according to menopausal status, an association between tumor dimension and SLN positivity was found in premenopausal women (OR 1.1, 95%CI 1.01-1.21; p &lt; .034), while in postmenopausal pts LVI was associated with SLN positivity (OR 3.05, 95%CI 1.65-5.64; p &lt; .0004).

Conclusions: Our data suggest that in a population with favorable early breast cancer (luminal subtypes, postmenopausal status and small tumour size) LVI increases the risk of SLN metastasis. These results are confirmed in luminal subgroup. In addition the absence of LVI has a significant negative predictive value. As far as menopausal status is concerned we found that the positivity of SLN is associated with tumor dimension in premenopausal and with LVI in postmenopausal women.

Citation Format: Nicla La Verde, Chiara Casiraghi, Chiara Dazzani, Irene Floriani, Elena Biagioli, Andrea Cordovana, Chiara Gerardi, Gabriella Farina, Anna Maria Croce, Filippo Bianchi, Claudio Lunghi, Mauro Lamera, Marcello Bonavita, Elena Bernardin, Giorgio Gherardi. Role of age, menopausal status and biological tumor characteristics on sentinel lymph node metastasis in early breast cancer patients with favorable prognostic features: A retrospective, mono institutional study on 345 cases [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-26.