Abstract P3-08-18: Risk of breast-cancer recurrence after a 10-year disease-free interval
Authors: Vertongen Anne-Sophie , Wildiers Hans , Punie Kevin , Giuseppe Floris , Ignace Vergote , Berteloot Patrick , Van Gorp Toon , Smeets Ann , Van Nieuwenhuysen Els , Sileny Han , Nevelsteen Ines , Laenen Annouschka , Weltens Caroline , Janssens Hilde , Neven Patrick 
Published: March 2020

Abstract
Background: Breast cancer is a disease that can recur even after 20 years of diagnosis. At the moment it remains difficult to predict which women will have a late relapse as most scientific research is conducted for relapse within 10 years following diagnosis. A recent meta-analysis by Pan et al was the first to look at risk factors for relapse in the second decade after diagnosis. However this paper mostly included patients that were treated before the year 2000, which makes the results less applicable to patients nowadays.
Objective: We retrospectively explored known early relapse risk factors for late relapse in a population that was diagnosed between year 2000 and 2008, 10-year disease-free and treated in one center.
Patients and methods: We included all patients, diagnosed with invasive breast cancer who remained disease-free for 10 years. We selected these from a prospectively managed database of consecutive treated patients in the University Hospitals Leuven for early breast cancer, diagnosed between 01-01-2000 and 01-08-2008. We analyzed the association of patient and tumor characteristics for relapse during the second decade after diagnosis. A disease-free survival event (invasive or in situ) was defined as local (ipsi- and contralateral breast), loco-regional (ipsi- and contralateral axillary, internal mammary and subclavian lymph nodes) or metastatic. For the statistical analysis we used Cox proportional hazard models, with time to recurrence as response variable. Furthermore, a multivariable model of independent predictors was constructed using backward selection.
Results: 2757 patients were included with a median follow-up of 13.78 years since initial diagnosis (range=10.01-18.65). Out of this group, 179 patients (6,5%) had a disease-free survival event (6 were in situ carcinoma). The multivariate analysis showed a higher risk of relapse in patients with a younger age (HR=1.044, p=0.0002), higher BMI (HR=1.036, p=0.0243) and postmenopausal status at diagnosis (HR=2.266, p=0.0012), higher tumor grade (HR=1.943, p=0.0151), more lymph node involvement (HR=1.626, p&lt;0.0001) and HER-2 negativity (HR=0.378, p=0.0087). Tumor size, hormone sensitivity and ductal versus lobular carcinoma showed no significant results.
Conclusion: Several patient and tumor related factors proved to be significant independent risk factors for late relapse (&gt;10 years after diagnosis). Our findings may help to differentiate between patients with high and low risk of relapse beyond 10 years of treatment and in this way, provide them with a more personalized form of follow-up.
Citation Format: Anne-Sophie Vertongen, Hans Wildiers, Kevin Punie, Floris Giuseppe, Vergote Ignace, Patrick Berteloot, Toon Van Gorp, Ann Smeets, Els Van Nieuwenhuysen, Han Sileny, Ines Nevelsteen, Annouschka Laenen, Caroline Weltens, Hilde Janssens, Patrick Neven. Risk of breast-cancer recurrence after a 10-year disease-free interval [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-18.