ESPE Abstracts

Background: Less than 1% of breast cancer cases occur in women aged <25 years but young age at diagnosis is associated with an increased risk of recurrence and inferior survival compared to older patients. Breast tumours from young patients have an increased incidence of adverse pathological features; however it is not clear whether this fully explains poor outcomes.

Objective and hypotheses: The Prospective Study of Outcomes in Sporadic and Hereditary Breast Cancer (POSH) was designed to investigate factors affecting prognosis of young breast cancer patients in the UK. I will present data from this study as well as a general overview of the epidemiology of breast cancer in young women.

Method: Between 2000–2008, 2956 patients aged <41 years were recruited to the POSH observational study. Tumour pathology, disease stage, treatment received, overall survival (OS) and distant disease-free interval (DDFI) were assessed. To date we have any analysed the effect of ethnicity, obesity and family history on the outcome of this cohort.

Results: Median patient age was 36 years. Median tumour diameter was 22 mm, and 50% of patients had positive lymph nodes; 59% of tumours were grade 3, 33.7% were oestrogen receptor (ER) negative, and 24% were human epidermal growth factor receptor 2 (HER2) positive. Five-year OS was higher for patients with ER-positive than ER-negative tumours (85.0 vs 75.7%; P< .001), but by eight years, survival was almost equal. In multivariable analyses obesity and ethnicity were both significant independent predictors of OS and DDFI in ER-positive patients. A positive family history was not a significant independent risk factor for breast cancer outcome.

Conclusion: Young onset breast cancer is associated with poor outcomes and new treatment approaches are required in younger women with this disease.