Comparison of prognostic factors and survival outcome between gastrointestinal tract and cutaneous invasive malignant melanoma.

618 Background: Gastrointestinal melanoma (GIM) is a rare disease. The objective of this study is to compare the overall survival (OS), cancer specific survival (CSS) and prognostic factors of GIM to those of skin melanoma (SKM) using the Surveillance, Epidemiology, and End Results (SEER) registry. Methods: Patients diagnosed with invasive GIM (406) and SKM (173,622) between 1973 and 2008 were identified from the SEER database. Factors analyzed included age (18-40/41-60/61-100), gender, race (White/nonwhite), marital status, stage (localized/regional/distant), year of diagnosis (1973-87/1988-97/1998-2008), and type of treatment (radiotherapy (RT)/surgery). OS and CSS were evaluated using the Kaplan-Meier method. Cox proportional hazards regression analysis examined what factors were prognostic of survival. Results: The median age was 69 and 57 for patients with GIM and SKM, respectively. The GIM group was older with more advanced-stage cancer than the SKM group. Surgery was performed on 85% and 95%, while...