Change Of Clinical Features And Outcomes Of Adolescents And Young Adults (Aya) With Colorectal Cancer Over Time: Pooled Analysis Of 26,768 Patients In The National Cancer Database (Ncdb)

256 Background: The incidence of colorectal cancer (CRC) in younger patients (pts) is rising. The underlying etiology is unknown, and it is uncertain if disease biology and clinical features are changing over time. Methods: A retrospective study of pts data in the NCDB was performed to compare the clinicopathological features and outcomes of AYA with CRC over a 12-year period. Pts diagnosis period was dichotomized into older (2004 – 2009) and newer (2010 – 2015) eras. Uni- and multi-variable chi-square, logistic regression, and survival analyses were used for comparisons. Survival differences were assessed using Kaplan-Meier curves. Results: In total, 26,768 AYA (18-40yrs) with CRC were identified and included in the analysis: 45.8% (n = 12,268) from the older and 54.2% (n = 14,500) from the newer era. There were no differences between the 2 groups in gender distribution or levels of income and education. However, in the newer vs. older era, there was a greater proportion of non-white, non-black pts (7.2% vs. 6%; p = 0.0005) and pts diagnosed between the ages of 18-30 (21.1% vs. 18.8%; p < .0001). Pts in the newer era tended to have more comorbidities (8.6 vs 7.5%; p = 0.0012), left-sided tumors (77.5% vs. 76.1%; p = 0.04), and well-differentiated histology (12.0% vs. 8.3%; p < 0.0001). Newer era pts also had lower rates of metastatic disease at presentation (15.3% vs. 18.2%; p < 0.001%) and nodal involvement (54.9 vs. 58.4%; p < 0.001%). Median OS of pts with stage IV disease appears to have improved over time (24.1 vs. 22.5 mos; p = 0.014). After controlling for age, race, primary tumor site and grade, presence of comorbidities, and health insurance status, older era pts with stage IV CRC were at a 15.1% greater risk of all-cause death by year 5 compared to newer era pts (HR adj = 1.15 (1.07-1.24, p = 0.0001). Conclusions: Our data suggest that AYA with CRC in more recent years tend to present at a younger age and have a lower rate of metastatic disease. They also have improved survival. Further investigation of AYA disease etiology and biology are warranted. Continued efforts to increase awareness, promote early detection, and improve treatment options are essential.