Prognostic value of lobular histology in breast cancer

In a poster presented at ESMO 2024, Dr Guilherme Nader-Marta (Dana Farber Cancer Institute, Boston, MA, USA) shared the results of a retrospective study evaluating the prognostic value of a lobular histology in patients with stage I-III breast cancer included in the Belgian Cancer Registry between 2008 and 2014.

In total, 51,696 patients were included in the analysis of whom 7,608 (14.7%) had an invasive lobular carcinoma (ILC). The remaining 44,088 patients (85.3%) did not have a specific histology (NST). Patients with ILC were more likely to have T3 (14.0% vs. 4.4%, p< 0.01) or N3 disease (5.6% vs. 2.9%, p<0.0001). In contrast, the rate of histological grade 3 patients was lower in ILC compared to NST patients (19.3% vs. 40.6%, p< 0.01). Patients with ILC had a significantly worse overall survival (OS) in an unadjusted analysis (HR[95%CI]: 1.13[1.07-1.18]), but this significance was lost after adjustment for T and N stage (HR[95%CI]: 1.0[0.95-1.05]). Interestingly, in the subgroup of patients with triple negative disease, an ILC histology was associated with a significantly worse OS than NST, even after adjustment for disease stage (HR[95%CI]: 1.91[1.15-3.16]). No statistically significant OS difference was observed between NST and ILC among patients with ER-positive and/or HER2-positive breast cancer.

In conclusion, a lobular histology is associated with a more advanced disease stage at diagnosis leading to a worse OS. This adverse impact on survival was particularly pronounced in patients with triple-negative breast cancer.