Survival analysis of patients with early and standard onset colorectal cancer: A single center study.

e15512 Background: While more aggressive clinical/pathological features have been consistently described in between patients with early-onset (EO) and standard-onset (SO) colorectal cancer (CRC), survival data have been conflicting. While some studies report better survival rates for EO-CRC; others found that outcomes among groups are not different. In a prior study, using the Surveillance, Epidemiology and End Results (SEER), we reported that cancer-related survival did not differ between EO-CRC and SO-CRC; however, a main limitation was the lack of molecular status and treatment details among groups. This study aims to compare the survival of EO-CRC and SO-CRC patients at Montefiore Medical Center. Methods: Retrospective cohort among 690 patients diagnosed with metastatic colorectal cancer (CRC) at Montefiore Medical Center between 2010 and 2018. Patients were identified using the software Clinical Looking Glass and charts were reviewed manually to gather information about demographics (race/ethnicity defined as Non-Hispanic White [NHW], Non-Hispanic Black [NHB] and Hispanic [H], gender, comorbidity index, calculated using the Charlson comorbidity score), clinicopathological features (grade, tumor sidedness, K-ras mutation) and treatment-related characteristics (metastatectomy, lines of chemotherapy and use of biologics). EO-CRC was defined as CRC diagnosis before age 50 and SO-CRC as CRC diagnosed at 50 years or older. Overall survival was compared between EO-CRC and SO-CRC using Kaplan Meier and Cox regression analyses. Stata v15.1 was used for statistical analysis. Results: Of 690 patients with CRC, 139 (20.1%) had EO-CRC and 551 (79.9%) had SO-CRC. Participants with EO-CRC had a higher frequency of poorly-differentiated tumors (35.5% vs. 23.8%, p = 0.02), a lower comorbidity index (6 vs. 7, p < 0.001). and a higher use of biologics (70.5% vs. 60.8%, p = 0.03) compared to SO-CRC. K-ras mutation was available for 377 (54.5%) of cases and did not differ among groups (45.9% vs. 45.9%, p = 0.99). In a model adjusted for race/ethnicity, gender, comorbidity index, sidedness, use of biologics and metastatectomy, there was no difference in mortality among groups (HR:0.9, 95%CI: 0.58 – 1.43, p = 0.68). This result remained unchanged in a model restricted to patients with available K-ras-status (n = 75), adjusted for all these variables. Conclusions: Despite more aggressive clinical/pathological features in patients with EO-CRC, survival does not differ compared to SO-CRC.