The epidemiology and demographic statistics of serrated adenocarcinoma.
Authors: Chin Kat , Choe Sharon , Grover Jasika , Harirchian Shervin , Nguyen Jacqueline , Gonzalez Karissa , Loken Delaney , Silberstein Peter T. , Lee Daniel , Demangone Michael , Rossi Anthony , Heise Craig , Hsia Beau 
Published: June 2024

e15645

Background: Serrated adenocarcinoma (SAC) is a recently-recognized variant of colorectal cancer (CRC) arising from precursor lesions of the serrated neoplastic pathway. Despite its novelty, SAC makes up around 10% of all CRCs and demonstrates worse patient prognosis than other forms. As rates of CRC, one of the most common cancers worldwide, continue to rise, further investigation must be done into new variants like SAC to improve its survivability and patient quality of life. This National Cancer Database (NCDB) analysis aims to evaluate the epidemiological factors and clinical characteristics of patients diagnosed with SAC. Methods: The 2004-2020 NCDB records were searched for patients with histologic diagnosis of SAC (N = 171) with the ICD-O-3 code 8213. This study utilized descriptive statistics to analyze demographics factors including age, sex, race, Hispanic status, educational attainment, insurance status, facility type, and Charlson-Deyo score. Results: From 2005-2020, 171 patients with an average age at diagnosis of 70.5 ± 11.3 years were diagnosed with serrated adenocarcinoma, with most (88%) cases demonstrating invasive behavior in the ascending colon (37%) or cecum (21%). The size of the tumors ranged from 1 - 200 mm, with an average size of 30.0 mm. The overwhelming majority of patients were white (93%) women (60%) living on average no more than 20 miles away from a hospital in metropolitan areas with populations over a million (49%). More patients were insured through Medicare (66%), receiving treatment at comprehensive community cancer (37%) or academic research programs (30%). Nearly all patients (95%) underwent surgery at the primary site, with a ninety-day survival rate of 88%. Among these, the most common procedure was subtotal colectomy or hemicolectomy (43%) followed by partial colectomy with segmental resection (22%), with 84% of patients showing no residual tumor after surgery. Alternate treatments included were chemotherapy (19%) and radiation therapy (8%). After five years, 68% of patients were alive, with the number falling to 35% after ten years. Conclusions: This study is the first on SAC to analyze NCDB data, presenting a larger sample than prior literature. With the commonality of colorectal cancer, the lack of research on SAC represents a significant knowledge gap. Interestingly, the data suggests that SAC predominantly develops in the ascending colon and cecum, conflicting with prior literature which suggested its tumors were more evenly distributed. Demographically, its diagnosed patients are mostly elderly, non-Hispanic whites insured by Medicare living in dense metropolitan areas near hospitals. These findings implicate that rural, aging communities could be impacted more severely by SAC, as they lack the healthcare infrastructure to obtain a proper diagnosis. To better define the link between demographic factors and effective diagnosis and treatment, further research is needed.