P3817 - Characterizing 5-Year Survival in U.S. Adults Diagnosed With Advanced Stage Colorectal Cancer Using the SEER Registry 2000-2021.

Mohamed Hisham Siddeek, MD¹, Salma Shariff-marco, PhD², Meg Mckinley, PhD², Ma Somsouk, MD, MAS^3
1UCSF School of Medicine, San Francisco, CA; ²UCSF, San Francisco, CA; ³University of California San Francisco, San Francisco, CA

Introduction: While trends in colorectal cancer (CRC) incidence and mortality have improved, limited data is available on the trends in stage-specific survival. A recent screening colonoscopy trial suggested that the mortality benefit did not achieve significance. Given the likely advances in treatment for advanced-stage CRC, the objective of this study was to examine the trends in survival after a diagnosis of CRC.  

Methods: This retrospective cohort study utilized the SEER 22 registry from 2000-2021. Trends in 5-year survival probabilities were analyzed by year of diagnosis for stage 3 and 4 CRC. The International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3) was used to identify all cases of CRC from 2000 to 2021. Patients with unknown age and/or staging, non-primary CRC, and appendiceal tumors were excluded from the study. The annual survival percentage change and 95% confidence interval were calculated. The primary outcome was the unadjusted 5-year % change in survival according to late-stage CRC, first by combining stage 3 and 4 CRC, and then by stage-specific survival. Additional covariates were extracted for adjustment in the multivariable model though not performed in this analysis included age, sex, race, ethnicity, neighborhood socioeconomic status (SES), region, insurance status, histology type, and treatment modality.

Results: Initial results indicate an overall increase in 5-year survival % change over time for patients diagnosed with stage 3 and 4 CRC. Survival in those diagnosed with CRC in 2000 was 63.1% compared to 2016 which was 65.6%. When comparing stage-specific 5-year survival in 2000 to 2016, patients with stage 3 CRC were found to have a higher % survival 69.5 vs 74.1%. A similar trend was noted in patients diagnosed with stage 4 CRC with 5-year % survival of 12.4 vs 15.6%.

Discussion: Survival has improved for patients diagnosed with late-stage CRC. Advances in therapeutic management may in part explain the observed decreased survival differences in patients exposed to screening versus no screening. Future analyses will include expanded capture of CRC cases, SEER regions, and adjustment for clinical covariates.


Disclosures:


Mohamed Hisham Siddeek, MD¹, Salma Shariff-marco, PhD², Meg Mckinley, PhD², Ma Somsouk, MD, MAS³. P3817 - Characterizing 5-Year Survival in U.S. Adults Diagnosed With Advanced Stage Colorectal Cancer Using the SEER Registry 2000-2021., ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.