Surgical and systemic treatment of lobular breast cancer

A maximum of 15% of women with breast cancer suffer from the lobular type, which has its own biological profile. Therefore, this type of breast cancer clearly differs from the ductal type of breast cancer, which is more common. Differences include epidemiological and radiological aspects, clinical and pathological features and the course of the disease. However, treatment regimens differentiate only little between these types of breast cancer, despite the differences listed above.The studies described in this dissertation evaluate surgical treatment (breast-conserving surgery versus amputation), systemic treatment (hormone therapy and chemotherapy) and pathological features of lobular breast cancer. The aim is to further individualise the current treatment of patients with lobular breast cancer

Estrogen and progesterone receptor expression levels do not differ between lobular and ductal carcinoma in patients with hormone receptor-positive tumors

Background Differences in estrogen (ER) and progesterone (PR) expression between invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) could be an underlying reason for the difference in chemo-sensitivity and response to hormonal therapy between ILC and IDC. The aim of this study was to investigate the differences in ER and PR expression levels between postmenopausal patients with hormonal receptor-positive ILC and IDC. Methods We included all ER and/or PR receptor-positive ILC and IDC, diagnosed between January 2011 and December 2013 from the population-based Netherlands Cancer Registry. A semi-quantitative classification was used to analyze differences in ER/PR expression, which consisted of three ER expression classes: 10–69, 70–89, and ≥90%. Differences in ER and PR expression levels between IDC and ILC were analyzed according to age group, tumor size, axillary nodal status, grade, and HER2 status. Results In total, 26,339 ER and/or PR-positive breast cancers were included in the study, of which 17% were ILC and 83% IDC. In patients with IDC, 86% of the tumors showed an ER expression level of 90% or more, compared to 84% in those with ILC. In both IDC and ILC a PR expression level of 90% or more was observed in 54% of the tumors. In postmenopausal patients aged 50–69 years no significant differences could be observed in ER and PR expression levels between ILC and IDC. Conclusion Patients with ER and PR-positive ILC and IDC have similar quantitative ER and PR expression profiles, implicating that ER/PR expression is unlikely to be a confounding factor in studies concerning chemo-sensitivity of ILC and IDC

Sentinel Lymph Node Biopsy and Isolated Tumor Cells in Invasive Lobular Versus Ductal Breast Cancer

Background Sentinel lymph node (SLN) biopsy is the standard of care for axillary staging in invasive breast cancer. The introduction of SLN biopsy with an extensive pathology examination, in addition to the introduction of the 2002 TNM classification, led to different axillary classification outcomes. We evaluated the effect of axillary staging procedures and subsequent axillary nodal status in patients with invasive lobular carcinoma (ILC) versus invasive ductal carcinoma (IDC) from 1998 to 2013. Materials and Methods The use of SLN biopsy and the nodal status distribution were analyzed in patients with stage T1-T2 ILC and IDC. Logistic regression analysis was performed to determine the independent effect of histologic type on the probability of the presence of isolated tumor cells (ITCs), micrometastases, and macrometastases. Results A total of 89,971 women were diagnosed, 10,146 with ILC (11%) and 79,825 with IDC (89%). The patients who had undergone SLN biopsy were more frequently diagnosed with ITCs than were those who had undergone axillary lymph node dissection only (odds ratio, 8.8; 95% confidence interval, 7.0-11.2). In 2013, the proportion of patients with ITCs in the axillary nodes was 8% in those with ILC and 4.4% in those with IDC. Patients with ILC were significantly more likely to have ITCs in their axillary lymph nodes than were patients with IDC (odds ratio, 1.8; 95% confidence interval, 1.6-2.0). Conclusion With the introduction of SLN biopsy and the renewed 2002 TNM classification, patients with ILC have been more frequently diagnosed with ITCs than have patients with IDC. The clinical consequence of this finding must be established from further research

The role of histological subtype in hormone receptor positive metastatic breast cancer: similar survival but different therapeutic approaches

INTRODUCTION: This study describes the differences between the two largest histological breast cancer subtypes (invasive ductal carcinoma (IDC) and invasive (mixed) lobular carcinoma (ILC) with respect to patient and tumor characteristics, treatment-choices and outcome in metastatic breast cancer. RESULTS: Patients with ILC were older at diagnosis of primary breast cancer and had more often initial bone metastasis (46.5% versus 34.8%, P = 0.01) and less often multiple metastatic sites compared to IDC (23.7% versus 30.9%, P = 0.11). Six months after diagnosis of metastatic breast cancer, 28.1% of patients with ILC and 39.8% of patients with IDC had received chemotherapy with a longer median time to first chemotherapy for those with ILC (P = 0.001). After six months 84.8% of patients with ILC had received endocrine therapy versus 72.5% of patients with IDC (P = 0.0001). Median overall survival was 29 months for ILC and 25 months for IDC (P = 0.53). MATERIALS AND METHODS: We included 437 patients with hormone receptor-positive IDC and 131 patients with hormone receptor-positive ILC, all diagnosed with metastatic breast cancer between 2007–2009, irrespective of date of the primary diagnosis. Patient and tumor characteristics and data on treatment and outcome were collected. Survival curves were obtained using the Kaplan-Meier method. CONCLUSIONS: Treatment strategies of hormone receptor-positive metastatic breast cancer were remarkably different for patients with ILC and IDC. Further research is required to understand tumor behavior and treatment-choices in real-life