Long-term outcomes and treatment response in early-stage invasive lobular carcinoma: insights from a nationwide population-based study

Nader-Marta, G; Ameye, L; Martins-Branco, D; Salgado, R; Van Damme, N; Verbeeck, J; Aftimos, P; Buisseret, L; Paesmans, M; Molinelli, C; Mayer, EL; Lambertini, M; Van Baelen, K; Desmedt, C; Piccart, M; de Azambuja, E

Author(s): Nader-Marta, G; Ameye, L; Martins-Branco, D; Salgado, R; Van Damme, N; Verbeeck, J; Aftimos, P; Buisseret, L; Paesmans, M; Molinelli, C; Mayer, EL; Lambertini, M; Van Baelen, K; Desmedt, C; Piccart, M; de Azambuja, E;
Details: Publication Year 2026-06-12,Volume 11,Issue #7,Page 107731
Journal Title: ESMO Open
Publication Type: Research article
Abstract: BACKGROUND: Invasive lobular carcinoma (ILC), the second most common breast cancer subtype, differs from invasive breast carcinoma of no special type (BC-NST) in biology, presentation, and treatment response. Evidence on its prognostic impact remains inconsistent. PATIENTS AND METHODS: Our nationwide, population-based study of stage I-III breast cancer diagnosed in Belgium (2008-2014) compared characteristics, treatment patterns, and overall survival (OS) between ILC and BC-NST. RESULTS: Of 51 815 eligible patients, 7593 (14.6%) had ILC. Compared with patients with BC-NST, patients with ILC were older (median 62 versus 59 years), more often T3-T4 (16.5% versus 7.4%) or N3 (5.4% versus 2.9%), and less frequently grade 3 (19.3% versus 40.7%; P < 0.0001). ILC was associated with worse unadjusted OS [hazard ratio (HR) 1.13, 95% confidence interval (CI) 1.08-1.18], with 15-year OS of 62.1% (versus 65.9% for BC-NST), but no difference after adjustment [adjusted HR (aHR) 0.97, 95% CI 0.92-1.02]. In subgroup analyses, inferior OS persisted in patients with N3 disease (aHR 1.29, 95% CI 1.07-1.55) and in those treated with neoadjuvant therapy (aHR 1.27, 95% CI 1.06-1.52). Flexible parametric models demonstrated a time-dependent effect, with lower early mortality but higher late mortality in ILC. Patients with ILC had lower odds of response to neoadjuvant therapy overall (odds ratio 0.34, 95% CI 0.27-0.43), consistent across hormone receptor-positive/human epidermal growth factor receptor 2-negative and triple-negative subtypes. CONCLUSIONS: The apparent survival disadvantage of ILC is largely explained by clinicopathologic features, with no independent association with OS. However, ILC demonstrates a time-dependent survival pattern, with lower early but higher late mortality, and worse outcomes in patients with extensive nodal involvement.
Publisher: Elsevier
Keywords: breast neoplasms; ductal breast carcinoma; lobular carcinoma; neoadjuvant therapy; prognosis
Department(s): Laboratory Research
Publisher's Version: https://doi.org/10.1016/j.esmoop.2026.107731
Open Access at Publisher's Site: https://doi.org/10.1016/j.esmoop.2026.107731
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2026-06-30 03:12:32

Last Modified: 2026-06-30 03:12:41