522 Background: The incidence of early-onset colorectal cancer (EO) is increasing. Guidelines recommend to start screening colonoscopy at 45 yo in Non-Hispanic Black (NHB). We compare the clinical features and outcomes between EO and standard-onset (SO) colorectal cancer (CRC) among racial groups. Methods: Patients with CRC adenocarcinoma; available race/ethnicity and stage were identified using the SEER registry. Clinical features and 5 year-overall survival (OS) is described by racial and age groups. Results: 190 670 patients were identified. EO rates were higher for minorities than NHW. Median age at diagnosis in EO was 44 and was similar among racial groups; while it was 71 in SO, being lower among minorities compared to NHW (67 vs. 72 years, p < 0.01). Left-sided tumors accounted for 77.4% of tumors in EO while it was 60.8% in SO for minorities versus NHW. The most common CRC location for EO was the rectum and sigmoid colon for SO. EO was most commonly diagnosed as stage III. Surgery and radiation rates were higher for EO for all stages. OS was higher in all stages of EO compared to SO. Conclusions: EO frequency is higher in all minority groups and most commonly located in the rectum. Despite higher stage and grade, OS is higher for EO which might be due to higher treatment rates. Early screening should be extended to all minority groups. [Table: see text]

16 Background: Randomized clinical trials have demonstrated the survival benefit provided by the addition of biologic drugs to chemotherapy (biochemotherapy) in patients with metastatic colorectal cancer (mCRC). However, Hispanic patients are underrepresented in trial populations with limited data on treatment efficacy in them. We aim to compare effectiveness of chemotherapy vs biochemotherapy among Hispanic population in the US with mCRC. Methods: This study includes two cohorts of patients: 1. age ≥ 65 years mCRC diagnosed from 2004 to 2011 who had received at least 1 dose of chemotherapy and had complete Medicare claims data using the Surveillance, Epidemiology, and End Result (SEER)–Medicare linked database, and 2. local Hispanic population from two hospitals in Bronx, New York, from 2006- 2020. Patient data were classified according to whether they received chemotherapy (oxaliplatin, irinotecan, and 5-fluorouracil or capecitabine) or biochemotherapy (bevacizumab, cetuximab, panitumumab, ramucirumab, or aflibercept, started within 3 months of chemotherapy). Overall survival (OS) was defined as the time from starting chemotherapy to death or last follow-up. A weighted Cox regression model was used to assess differences in survival. Results: A total of 188 patients with mCRC were identified. Fifty three (28.2%) received chemotherapy and 135 (71.8%) received biochemotherapy. Median ages were 69 and 68 years, respectively. There were no differences based on median income, marital status, primary site or sidedness, tumor differentiation grades or Charlson Comorbidity Score between both groups. Among patients who received only chemotherapy, 9% received second or greater lines of chemotherapy when compared to 51% in the biochemotherapy group (p <0.001). The median overall survival was 6.6 (95% CI:5.7 - 15.0) months (mo) and 15.9 (12.0 -24.5) mo, respectively. Biochemotherapy conferred an OS benefit with average HR=0.62 (0.41-0.94; p=0.023). This was most evident in the first year (HR=0.53, 0.31-0.89; 0.016), less so in 2nd year (HR=0.65, 0.28 - 1.49; 0.307) and there was an apparent reversal effect beyond 2 years (HR=1.79, 0.41-7.77; 0.436). Conclusions: In this comparative effectiveness study of a cohort of Medicare recipients and the Bronx population, with mCRC, biochemotherapy was associated with an improvement in OS, especially in the 1st year. Patients receiving biochemotherapy are more likely to receive further lines of chemotherapy upon disease progression.

e15089 Background: Early-onset colorectal cancer (EO-CRC) incidence is increasing disproportionately among minorities compared to Non-Hispanic Whites (NHW). EO-CRC have aggressive features such as higher grade and advanced stages. The appropriate age to start screening colonoscopy (SC) in NHW and minorities remains controversial; varying between 45 and 50 years old. We aim to compare EO-CRC clinico-pathological characteristics and survival rates by race groups. Methods: Patients with colorectal adenocarcinoma (CRC) with available race and stage as per AJCC 6th edition were identified using the SEER registry (1973-2010). EO-CRC was defined as CRC before age 50 years. Clinico-pathological features, overall survival (OS) by Kaplan Meier curves and mortality predictors by multivariate analysis were evaluated by race groups. Results: 180 605 patients with CRC were identified; 10.2% had EO-CRC. Mean age of diagnosis was 42.7 years and EO-CRC frequency was higher in minorities (Hispanics (H):16.7%, Non-Hispanic Black (NHB):12.7% and Asian (A): 12.8%) compared to NHW (8.7%). EO-CRC in NHB was predominantly seen in females. The rectum was the most common location for all races. Two-thirds of tumors were located between the sigmoid and anal regions in all races except NHB that had higher frequencies of right-sided tumors. Compared to other races, NHB had worse OS at all stages and tumor locations. NHB was associated with 72% increased risk of death by multivariate analysis. Conclusions: Our data suggest that EO-CRC frequency, pathological features and OS differ by race group; hence SC guidelines should be tailored accordingly. SC would be considered early; especially in minorities. Complete colonoscopy should be considered for NHB given higher rates of right-sided tumors and worse OS; while sigmoidoscopy may be adequate for others up to age 50, given higher rates of tumors located in the sigmoid to anal region. [Table: see text]