Outcomes of Adolescent and Young Adult Women With Breast Cancer in Rural and Urban Saskatchewan: A Retrospective Cohort Study.

Abstract

Breast cancer is uncommon in adolescent and young adult (AYA) women, accounting for approximately 1.8% of all breast cancers. There is a risk of delayed diagnosis of breast cancer among AYA women, especially among those residing in rural areas. The aim of this study was to assess the outcomes of AYA women for breast cancer in relation to rural residence. This cohort study evaluated all women aged 35 years and younger with histologically confirmed breast cancer diagnosed between 2000 and 2019 in a Canadian province. A multivariate Cox proportional hazards model was used to assess the prognostic significance of rural residence and other variables for overall survival (OS) across all stages and disease-free survival in early-stage breast cancer. A total of 248 eligible AYA women with a median age of 32 years were identified, of whom 24% were younger than 30 years. Of all patients, 51% had node-positive disease, and 11% had stage IV disease at diagnosis. Among those with invasive breast cancer, 45% had hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative disease; 30% had HER2-positive disease; and 25% had triple-negative breast cancer (TNBC). There were 53% rural and 47% urban residents. In multivariate analysis for OS for stage 0 to IV disease, rural residence (hazard ratio [HR], 1.75 [95% CI, 1.08 to 2.81]), TNBC (HR, 2.25 [95% CI, 1.34 to 3.80]), and stage IV disease (HR, 8.1 [95% CI, 4.72 to 13.94]) were associated with inferior OS. AYA women with breast cancer have a high incidence of node-positive disease and aggressive subtypes. This study found a significant association between rural residence and OS. These findings emphasize the need for enhanced early detection and personalized treatment strategies, particularly for rural patients and those with TNBC.