Invasive Pleomorphic Lobular Histology Is an Adverse Prognostic Factor on Survival in Patients with Breast Cancer

Abstract

Invasive pleomorphic lobular carcinoma (IPLC) is defined to be an uncommon and different subtype of classical invasive lobular carcinoma (ILC). This special variant is characterized by significant cytological atypia and pleomorphism which differs from the cytological uniformity of ILC. IPLC has been shown to have some poor prognostic factors such as axillary node metastasis and higher histological grade which may lead to poor clinical courses including a short relapse time, increased risk of recurrence and a decreased survival. The aim of this study is to investigate the clinicopathological characteristics and prognosis of IPLC in comparison with ILC and also to evaluate if IPLC is a different clinical entity compared to ILC. A total number of 4418 breast cancer patients treated between 1996 and 2015 in Hacettepe University Cancer Institute, were retrospectively analyzed. Among 4418 patients, 210 were diagnosed with ILC and 23 patients diagnosed with pure IPLC. In this present study, clinicopathological characteristics, disease free survival (DFS) and overall survival (OS) of patients with ILC and IPLC were compared. This study design is one of the rare face to face comparison of pure IPLC and ILC. Patients with IPLC had an increased rate of higher histologic grade, extracapsular extension, lymphovascular invasion and lower percentage of hormone positivity than those of patients with ILC. During the follow-up time, IPLC group experienced 4 cases (17.3%) of recurrence, 5 cases (21.7%) of death and 2 cases (8.7%) of progression in 3 metastatic patients compared to that of 27 cases (12.9%) of recurrence, 29 cases (13,8%) of death and 14 cases (6.7%) of progression in 19 metastatic patients in the ILC group. Patients with IPLC had a worse DFS and OS duration than patients with ILC (P = 0.02 for OS, P = 0.04 for DFS). In conclusion, IPLC is a different and a special breast cancer subtype. This study suggests that IPLC is a distinct clinical entity with an advanced stage and more aggressive clinical course. Patients with IPLC reveal poorer prognostic factors such as higher histological grade, relative lower percentages of hormone positivity, and increased rate of recurrences resulting in poor clinical outcomes and worse survival. Nowadays, it is observed that current treatment methods for IPLC do not seem as successful as in ILC and failed to be effective. Thence, individual therapies including more aggressive surgery and adjuvant or neoadjuvant chemotherapy even in the earlier stages of breast cancer should be performed for this distinct variant.