e19001 Background: aBCC is defined as (1) locally advanced BCC (inoperable or surgery contraindicated) with disease progression after radiation (unless radiation contraindicated), or (2) metastatic BCC. Information on aBCC patient demographics, or clinical and treatment characteristics is limited. The purpose of this descriptive study is to characterize aBCC patients receiving care within the US Oncology (USO) network. METHODS Patients with a diagnosis of aBCC between July 1, 2006 to June 30, 2010 were included. From an initial pool of 278 BCC patients, AJCC staging 6th ed. (Stage III, IV) and metastatic status were used to identify aBCC patients. Detailed Electronic Medical Records (EMR) and physical chart reviews were conducted on identified patients to collect information on patient demographics, clinical characteristics, and current and historical treatment characteristics. Analyses were primarily descriptive. RESULTS 41 patients were treated at USO clinics for aBCC. Mean age was 72 years, males comprised 68%, and mean Charlson Comorbidity Score was 0.97. 11 patients developed metastases. Sites of advanced disease were in the head/neck area (54%), extremities (10%), trunk (5%) and other (32%). Before progression to aBCC, patients received BCC-related surgeries (12 or 29%), radiation (9 or 22%) and chemotherapy (1 or 2%) while post aBCC diagnosis, patients received surgeries (24 or 59%), radiation (28 or 68%) and chemotherapy (13 or 32%), where each patient could have more than one procedure. Before progression to aBCC, there were 2 Moh's surgeries and 2 excisions while post aBCC diagnosis, there were 6 Moh's surgeries and 15 excisions. Among 20 chemotherapy regimens post diagnosis to aBCC, 15 were platinum based. These patients saw several types of physicians, namely radiation oncologists (34%), medical oncologists (29%), dermatologists (21%), surgical specialists (12%), and primary care physicians (4%). CONCLUSIONS aBCC is an uncommon but serious condition, for which there appears to be no commonly accepted approach to therapy. Even in a national oncology community group, there is no consistent pattern of care for aBCC patients, suggesting that more research and options are needed.