Abstract P6-06-16: Young age as a good prognostic factor in de novo metastatic breast cancer

Abstract

Abstract Background While breast cancer is relatively rare in young women under the age of 40, its incidence is increasing and accounts for up to 40% of all female cancers. Young age at diagnosis is associated with a poorer prognosis in early breast cancers; however little is known about the natural history of young women with metastatic breast cancer. We aim to evaluate the effect of age on breast-cancer specific survival (BCS) and overall survival (OS) for patients with de novo metastatic breast cancer using data from the SEER registry. Methods We retrospectively analyzed 14155 patients with de novo metastatic breast cancer from the SEER registry between 2000 and 2009. Young women were defined as 50 years and below and further subdivided into three groups: 20-34, 35-39, and 40-49 years. Age 50-69 years served as a comparison group. Unadjusted overall survival (OS) and breast cancer specific survival (BCS) were accessed using Kaplan-Meier plots and compared across groups using log-rank tests. Cox proportional hazards models were then fitted to determine the association between survival end point and age after adjusting for patient and tumor characteristics. Results 546 (3.9%) patients were age 20-34 years, 750 (5.3%) were 35-39 years, 3049 (21.5%) were 40-49 years and 9810 (69.3%) patients were 50-69 years. Median BCS among patients age 20-34, 35-39, 40-49 and 50-69 years was 30, 33, 35, 28 months respectively (P<0.0001). Median BCS among patients with estrogen receptor positive disease who were age 20-34, 35-39, 40-49 and 50-69 years was 43, 42, 51, 37 months respectively (P<0.0001). Similarly median BCS among patients with estrogen receptor negative disease who were age 20-34, 35-39, 40-49 and 50-69 years was 21, 18, 18, 17 months respectively (P<0.0001). In the multivariable model compared to patients who were age 50 -69 years those aged 20-34 years (HR 0.88, 95% CI 0.78-0.99), 35-39 years (HR 0.82, 95% CI 0.74-0.91) and 40-49 years (HR 0.84, 95% CI 0.79-0.89) had a significantly decreased risk of death from breast cancer. Similar results were obtained for OS. Conclusion Younger patients defined by age less than 50 years had a better BCS and OS when compared against older age group in the setting of de novo metastatic breast cancer. This may be explained by lack of important comorbidities, relatively good performance status as well as ability to tolerate more lines of chemotherapies. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-16.