Abstract P1-12-09: Proposal for integrating the pathologic assessment of lymphovascular invasion and extranodal tumor extension in breast cancer-related lymphedema clinical management
Authors: Fusco N , Corti C , Lopez G , Michelotti A , Despini L , Gambini D , Lorenzini D , Guerini-Rocco E , Maggi S , Noale M , Invernizzi M 
Published: May 2019

Breast cancer related lymphoedema (BCRL) occurs in a substantial proportion of breast cancer survivors and is a major contributor to disability, representing a long-term threat to these patients. Given the extremely high incidence of breast cancer worldwide, and the increasing number of long-term survivors, the reduction of BCRL burden represents an urgent clinical need in women's healthcare. However, there are no validated predictive biomarkers, diagnostic tools, and strong evidence-supported therapeutic strategies for BCRL management. Here, we provide a comprehensive clinicopathological characterization of a large series of women with node-positive breast cancers and identify new bona fide predictors of BCRL occurrence.

332 cases of surgically-treated node-positive breast cancers were retrospectively collected (2-10.2 years of follow-up). Among them, 62 patients developed BCRL. To identify demographic and clinicopathologic features related to BCRL, Fisher's exact test or Chi-squared test were carried out for categorical variables; the Wilcoxon rank-sum was employed for continuous variables. Factors associated with BCRL occurrence were assessed using a Cox proportional hazards regression model.

En-bloc dissection of the axillary lymph nodes but not the type of breast surgery impacted on BCRL development. Most of BCRL patients had a Luminal A-like neoplasm. The median number of lymph nodes involved by metastatic deposits was significantly higher in BCRL compared to the control group (p=0.04). Both peritumoral lymphovascular invasion (LVI) and extranodal extension (ENE) of the metastasis had a negative impact on BCRL-free survival (p=0.01). Specifically, patients with LVI and left side localization harbored 4-fold higher risk of developing BCRL, while right axillary nodes metastases with ENE increased the probability of BCRL compared to ENE-negative patients.

Here, we document that LVI and ENE have a strong predictive value for BCRL occurrence. Furthermore, we confirm that the full excision of the axillary nodes is one of the major determinants of BCRL, regardless of the extent of the surgical procedure involving the breast. In conclusion, our results suggest that the pathologic data on LVI and ENE should be integrated with information on the laterality of the tumor and the type of surgical procedure. This new integrative approach could be extremely beneficial to improve BCRL risk stratification.

Citation Format: Fusco N, Corti C, Lopez G, Michelotti A, Despini L, Gambini D, Lorenzini D, Guerini-Rocco E, Maggi S, Noale M, Invernizzi M. Proposal for integrating the pathologic assessment of lymphovascular invasion and extranodal tumor extension in breast cancer-related lymphedema clinical management [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-09.