Abstract PD6-01: Analysis of breast cancer in young women in the department of defense (DOD) database
Authors: Zimmer AS , Gatti-Mays M , Soltani S , Lipkowitz S , Steeg PS , Zhu K , Perkins JG , Hu H , Shao S , Brown D , Shriver CD 
Published: March 2017

Abstract
Background: Women under the age of 40 account for approximately 7% percent of breast cancer patients. Breast tumors from young women are often ER-negative, occur in African-American patients, and have other indicators of high risk: yet, multivariate analyses demonstrated that young age is an independent predictor of poor outcome. Due to the unique nature of the patient population served by DOD, a disproportionate number of breast cancer cases in young women are seen. We compare the characteristics, treatment, and outcomes of young patients diagnosed with breast cancer with those of older patients.
Methods: The databases of the Military Health System Repository and the DOD Central Registration were used to identify female breast cancer patients treated at DOD facilities between 1998 and 2007. Information on demographics, breast cancer stage at diagnosis, definitive surgical treatments, systemic treatment, recurrence rate and overall survival was analyzed by age groups at the time of diagnosis (less than 40 years old, 40 to 49 years, and 50 years or older) using X2 testing with significance defined as p&lt; 0.05.
Results: We identified 10,066 women who were diagnosed with invasive breast cancer at DOD facilities between 1998 and 2007, of which 11.3% (1139) were less than 40 years old at diagnosis. 53% of this young cohort were white, 25% were African-American and 8% were Hispanic (14% undisclosed). The percentage of breast cancer among African-American women in the young cohort was higher than in the older cohorts (19.3% in 40-49yo and 10.6% in ≥50yo). High-grade tumors were significantly more frequent in the younger cohort when compared to the older group (49.5% vs 34.7% and 25.2%, p&lt;0.001). &lt;40yo most commonly presented with Stage II disease (45.3%) at diagnosis, while older groups were mostly diagnosed with Stage I disease (41.6% and 52.4%). The most common subtype of breast cancer across ages was ER+ disease, however, &lt;40yo group had proportionally less ER+ (49% vs 61% and 67.3%, P&lt;0.001). There was a higher rate of bilateral mastectomies among the young women (18.4% vs 9.1% and 5.0%, p&lt;0.0001). Independently of the stage of disease, chemotherapy was given significantly more frequently to &lt;40y (90.43%) and 40-49yo (81.44%) than ≥50yo (53.71%). The 10-year overall survival of younger women was similar to the ≥50yo cohort, despite intensive treatment.
Discussion: This study is one of the largest retrospective studies of women under 40 years old with breast cancer. Younger women with invasive breast cancer had more aggressive tumors presenting at higher stages. In this group with good access to healthcare, younger women still had a similar overall survival rate to older women despite receiving more aggressive treatment and potentially having fewer comorbidities than the older group.
Citation Format: Zimmer AS, Gatti-Mays M, Soltani S, Lipkowitz S, Steeg PS, Zhu K, Perkins JG, Hu H, Shao S, Brown D, Shriver CD. Analysis of breast cancer in young women in the department of defense (DOD) database [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD6-01.