Outcome of invasive lobular carcinoma of breast in Malaysia

Abstract

Background: Breast cancer is the commonest cancer and 2^nd most common cause of cancer death among women worldwide. Histologically breast cancer can be divided into Invasive Lobular Carcinoma (ILC), Invasive Ductal Carcinoma (IDC) and others. ILC has its own unique patient’s demographic, histological appearance, imaging characteristics and clinical outcome. Previous published study has shown that ILC has better overall survival compared to IDC. Sadly, despite being so common, there is still lack of study comparing ILC and IDC in Malaysia setting. Methods: 5225 of patients diagnosed with ILC and IDC were managed in University Malaya Medical Center within 1993 to 2013 has been included in this study. Chi square test were performed to determine the demographic and clinical factors associated with ILC and IDC. Kaplen-Meier method was used to obtain overall survival of these patients. Through a Cox regression analysis, mortality in patients diagnosed with ILC and IDC were identified, by adjusting the possible confounding factors. Results: ILC is more common in elderly compared to younger patients. There is no association between ethnicity and types of invasive carcinoma. Patients with ILC were more likely to have lymph nodes involvement (p = 0.001), estrogen receptor positive (p = 0.001), absent of lymphovascular invasion (p = 0.028), mastectomy (p = 0.022) and hormonal therapy (p = 0.002) compared to IDC and it is statistically significant. Nevertheless, survival was not significantly different between ILC and IDC; 5-year OS; 77.4% (95% CI 77.34 to 77.46) and 71.3% (95% CI 71.29 to 71.30), respectively; the 10 year OS; 52.2% (95% CI 52.13 to 52.27) and 49.7% (95% CI 49.68 to 49.72), respectively. The adjusted hazard ratio comparing ILC and IDC using Cox regression was 1.21 (0.85 to 1.72) showing there is no significant difference between patients presented with ILC and IDC in terms of survival. Conclusion: Based on Malaysian data gathered from University Malaya Medical Center, there is no difference in survival outcome of patients presented with ILC or IDC.