Appropriate treatment for stage 1 and 2 HER 2 positive and triple-negative breast cancer by immigration status in Ontario, Canada.

Abstract

e12511 Background: This study explored the appropriateness of treatment received for stages 1 and 2 HER2-positive and triple-negative (TNBC) breast cancer (BC) patients with subtypes between immigrants and long-term residents. Methods: We identified women aged 18 – 75 years in the Immigration, Refugee, and Citizenship Canada Permanent Resident (CIC) database diagnosed with BC in Ontario from 2012-2019 and matched each to two long-term residents and linked to population-wide treatment databases. We categorized them into four mutually exclusive groups based on subtype (Her-2 positive vs triple negative) and breast surgery (breast-conserving surgery (BCS) vs mastectomy). Appropriate treatment included chemotherapy for all, (plus Herceptin if Her-2 overexpressing), plus breast radiation therapy if breast-conserving surgery was performed. We could not assess the receipt of endocrine therapy for the hormone receptor-positive subset of Her-2 overexpressors or indications for post-mastectomy radiation therapy. Odds ratios for receiving appropriate treatment were calculated using logistic regression adjusting for age, resource utilization and residential ethnicity concentration. Results: The analysis included 8490 women, 1538 immigrants, and 6952 long-term resident women who had a follow-up over one year. The mean age of immigrants (50.10(SD9.8)) was lower than long-term residents (54.70(SD11.13)) (p < 0.0001). Conclusions: Immigration status did not affect the receipt of appropriate treatment amongst early-stage breast cancer patients with Her2 positive or triple-negative breast cancer patients treated with either breast-conserving surgery or mastectomy in Ontario. Receipt of treatment for stages 1&2, HER2 + and triple-negative, breast cancer on adjusted analysis. Her2+ patients Breast-Conserving Surgery Mastectomy Adjusted odds Ratio 95%CL(p-value) Adjusted odds Ratio 95%CL(p-value) Immigrants vs long-term residents 0.82ref 0.65-1.04(0.09)ref 0.95ref 0.67-1.35(0.79)ref Triple Negative patients Breast-conserving Surgery Mastectomy Adjusted Odds Ratio 95%CL(p-value) Adjusted Odds Ratio 95%CL(p-value) Immigrants vs long-term residents 0.81ref 0.58-1.13(0.22)ref 0.85ref 0.49-1.46(0.55)ref