Cancer of unknown primary in adolescents and young adults: Clinicopathologic features, prognostic factors, and survival outcomes.

4140 Background: Cancer in adolescents and young adults (AYAs) (15-39 yrs) is increasingly recognized as a distinct clinical and biological entity. Cancer of unknown primary (CUP) although rare in young adults, poses a complex and unique challenge. Our study describes clinicopathologic features and outcomes in AYA-CUP patients (pts). Methods: We performed a retrospective review of 47 AYA pts diagnosed with CUP at The Univ. of Texas, MD Anderson Cancer Center, between 6/2006 and 6/2013. Data on demographics, imaging, pathology and treatment was collected from a prospectively maintained CUP database. Kaplan-Meier product limit method was used to estimate median overall survival (OS) and log-rank test was used for comparison. Cox proportional hazards model was used for multivariate analysis. Results: Median age was 35 years (19–39 yrs). Pts had comprehensive workup (CT 100%); PET scan, upper endoscopy, colonoscopy and mammography was performed in 60%, 51%, 47% and 40% pts, respectively; none yielding a prima...