M. B. Holbrook1, N. Bhutiani1, B. Huang2, Q. Chen2, T. C. Tucker3, S. Galandiuk1, R. W. Farmer1 1University of Louisville,Surgery,Louisville, KY, USA 2University of Kentucky,Biostatistics,Lexington, KY, USA 3University of Kentucky,Markey Cancer Center,Lexington, KY, USA
Introduction: Multiple studies have demonstrated an increase in rectal cancer among young people, a trend reflected in the most recent colorectal cancer screening guidelines. Despite significant improvement in screening and education, young rectal cancer patients have emerged as a burgeoning health crisis in Kentucky. This study sought to compare the incidence of rectal cancer and tumor biology among patients <40 years old in Kentucky and the United States.
Methods: The Kentucky Cancer Registry (KCR) and the National Cancer Database (NCDB) were queried for patients diagnosed with cancer of the rectum or rectosigmoid junction between 2004 and 2014. Demographics, tumor characteristics, and annual proportional incidence in patients <40 years old and those ≥ 40 years old were compared.
Results:Patients in Kentucky and nationally had a similar distribution between rectal junctional and true rectal malignancy (p=0.13). There was no difference in stage at diagnosis (p=0.17), gender (p=0.57), and KRAS mutational status (p=0.46). However, a greater proportion of patients in Kentucky had undifferentiated tumors compared to the NCDB (7.5% KCR vs. 1.8% NCDB, p<.001). Five-year overall survival was no different between groups (~70%). Linear regression of incidence demonstrated an annual increase in Kentucky of twice the national rate (0.13% per year vs 0.05% per year) with a sharp increase in 2014 (Figure).
Conclusion:While similar to the national cohort, young rectal cancer in Kentucky displays variation in tumor grade and incidence suggesting difference in tumor biology. These data reinforce recent changes to screening guidelines, with potential extension to younger patients.
