Lisa J Findlay-Shirras1,2, Isac Lima3,4, Glenys Smith3,4, Mark Clemons5, Angel Arnaout6,7,4. 1. Department of Surgery, University of Ottawa, Ottawa, ON, Canada. lisa.findlayshirras@gmail.com. 2. Department of General Surgery, The Ottawa Hospital, General Campus, Ottawa, ON, Canada. lisa.findlayshirras@gmail.com. 3. Institute of Clinical Evaluative Sciences (ICES), University of Ottawa, Ottawa, ON, Canada. 4. Ottawa Hospital Research Institute, Ottawa, ON, Canada. 5. Division of Medical Oncology, Department of Medicine, University of Ottawa, Ottawa, ON, Canada. 6. Department of Surgery, University of Ottawa, Ottawa, ON, Canada. 7. Department of General Surgery, The Ottawa Hospital, General Campus, Ottawa, ON, Canada.
Abstract
BACKGROUND: Invasive lobular carcinoma (ILC) is less common that invasive ductal carcinoma (IDC), and more challenging to diagnose by examination and screening mammography. This study evaluated current trends in ILC incidence, and described the 5-, 10-, and 15-year survival probabilities for women diagnosed with ILC in Ontario, Canada. METHODS: This retrospective cohort analysis included all women aged 18 years and older diagnosed with breast cancer between 1991 and 2015. Health administrative data from the Institute of Clinical Evaluative Sciences and the Ontario Cancer Registry were used to identify breast cancer cases. Age-adjusted incidence was plotted by year. Crude proportions were plotted by year of diagnosis for stage and hormone receptor status. Kaplan-Meier curves were generated to determine the 5-, 10-, and 15-year survival probabilities for ILC and IDC. RESULTS: From 1991 to 2015, there were 194,065 cases of breast cancer in Ontario, 14.7% of which were ILC. The age-adjusted incidence of breast cancer increased 1.04-fold, while ILC rates increased 1.53-fold. All bilateral breast cancers were of lobular origin. The proportion of stage 1 ILC decreased, while the proportion of stage 2-4 ILC increased. The 5-, 10-, and 15-year overall survival probabilities for women diagnosed with ILC were 82.7%, 65.3%, and 50.2%, respectively. CONCLUSIONS: This study contains the largest population dataset of ILC evaluated to date. While total breast cancer incidence rates in Ontario are largely unchanged, ILC incidence rates are steadily increasing and there is a trend towards diagnosis of ILC at a later stage. These trends highlight the ongoing diagnostic and treatment challenge ILC presents for patients and clinicians.
BACKGROUND:Invasive lobular carcinoma (ILC) is less common that invasive ductal carcinoma (IDC), and more challenging to diagnose by examination and screening mammography. This study evaluated current trends in ILC incidence, and described the 5-, 10-, and 15-year survival probabilities for women diagnosed with ILC in Ontario, Canada. METHODS: This retrospective cohort analysis included all women aged 18 years and older diagnosed with breast cancer between 1991 and 2015. Health administrative data from the Institute of Clinical Evaluative Sciences and the Ontario Cancer Registry were used to identify breast cancer cases. Age-adjusted incidence was plotted by year. Crude proportions were plotted by year of diagnosis for stage and hormone receptor status. Kaplan-Meier curves were generated to determine the 5-, 10-, and 15-year survival probabilities for ILC and IDC. RESULTS: From 1991 to 2015, there were 194,065 cases of breast cancer in Ontario, 14.7% of which were ILC. The age-adjusted incidence of breast cancer increased 1.04-fold, while ILC rates increased 1.53-fold. All bilateral breast cancers were of lobular origin. The proportion of stage 1 ILC decreased, while the proportion of stage 2-4 ILC increased. The 5-, 10-, and 15-year overall survival probabilities for women diagnosed with ILC were 82.7%, 65.3%, and 50.2%, respectively. CONCLUSIONS: This study contains the largest population dataset of ILC evaluated to date. While total breast cancer incidence rates in Ontario are largely unchanged, ILC incidence rates are steadily increasing and there is a trend towards diagnosis of ILC at a later stage. These trends highlight the ongoing diagnostic and treatment challenge ILC presents for patients and clinicians.
Entities:
Keywords:
Bilateral breast cancer; Breast cancer; Incidence rates; Lobular carcinoma
Authors: Mary Kathryn Abel; Amy M Shui; Michelle Melisko; A Jo Chien; Emi J Yoshida; Elizabeth M Lancaster; Laura Van 't Veer; Laura J Esserman; Rita A Mukhtar Journal: NPJ Breast Cancer Date: 2021-12-21
Authors: Keegan K Hovis; Janie M Lee; Daniel S Hippe; Hannah Linden; Meghan R Flanagan; Mark R Kilgore; Janis Yee; Savannah C Partridge; Habib Rahbar Journal: J Breast Imaging Date: 2021-04-29