Advocate Chat: Results from an ILC Study in Ontario, Canada

A Conversation with LBCA Grantee Dr. David Lim and Patient Advocate Christine McKay

On  March 28, 2023, the Lobular Breast Cancer Alliance (LBCA) Advocate Chat featured a discussion with our first invasive lobular carcinoma (ILC) research grantee Dr. David Lim and ILC research advocate and Patient Advocate Advisory Board (PAAB) member Christine McKay. The Chat included an overview by Dr. Lim of his recently concluded population-based study on ILC in Ontario, Canada. After sharing his findings, Dr. Lim and Christine talked about the importance of patient advocates in the development of research grant proposals.

Dr. Lim also shared a lay summary of his work:

The goals of this research were to analyze and compare the incidence and survival of the three breast cancer subtypes (pure ductal, pure lobular, and mixed ductal-lobular) over the last 30 years in the province of Ontario, Canada. We also wanted to find out if specific factors (either patient factors, tumour characteristics, or treatments received) were associated with better or worse survival in lobular breast cancer patients.

To perform these studies, we used publicly available administrative and healthcare databases at the Institute for Clinical Evaluative Sciences (ICES) Ontario. These datasets, such as the Ontario Cancer Registry, capture a wide range of demographic, cancer, and healthcare data for the 14.6 million population of Ontario.

From 1990 to 2020, we identified 192,371 ductal (81%), 18,551 pure lobular (8%), 10,234 mixed ductal-lobular (4%), and 15,903 other subtype (7%) breast cancers. The incidence rates of both pure ductal and lobular breast cancer is increasing over time, while that of mixed ductal-lobular peaked in the mid-2000s and is decreasing. Over the 30 year period, we found that beginning at 10 years after diagnosis, lobular breast cancer patients had worse overall survival than patients with ductal or mixed ductal-lobular breast cancer.

Various factors were found to be associated with better or worse overall survival. Older age, lower income, having more medical conditions, and living in certain geographic locations within Ontario predicted worse survival. Cancer-related factors associated with worse survival include stage 3 disease (versus stage 1), high-grade disease (versus low-grade), and estrogen-receptor/progesterone-receptor negativity. Receiving a staging breast MRI at diagnosis has increased over time and was associated with better survival. Compared with having lumpectomy, mastectomy was associated with worse overall survival. Chemotherapy use predicted worse overall survival while radiation use predicted better overall survival.

While our study has generated some interesting associations, the research was limited because of its retrospective nature, and we could not study use of endocrine therapy. Therefore, these associations cannot be considered definitive without further study, which we are currently pursuing.

LBCA provides information and tools to help individuals who want to educate others about lobular breast cancer. We also provide links to training resources for breast cancer research advocacy, which enable people to promote more ILC research. The LBCA’s Advocate Chat series provides people with a way to learn more about different aspects of patient advocacy and to network with other patient advocates.

Watch the Advocate Chat with Dr. Lim and Christine McKay below. Learn more about LBCA and advocacy by visiting our Advocacy through Education and Research Advocacy Toolkit pages and reading Research Advocacy Resources and Questions and Answers. For more information about lobular breast cancer or to make a gift visit lobularbreastcancer.org.

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