Observed Changes in the Distribution of Colon Cancer Metastasis: A National Cancer Database Review and Institutional Experience.

Background: The University of Louisville has observed a near 70% drop in resectable/borderline resectable metastatic colorectal cancer in the past 5 years. The aim of this study was to evaluate the distribution of colon cancer metastasis at diagnosis and at recurrence.

Patients And Methods: Stage was defined by the American joint committee on cancer (AJCC) eighth edition. Institutional review board approval was granted for post hoc review of stage II and III patients with colon cancer from the University of Louisville prospective hepatic database from 2002 to 2023, as well as for the National cancer database (NCDB) Participant user file (PUF) 2021. The Surveillance epidemiology and end-results (SEER) 22 database was also utilized to corroborate the findings in the NCDB.

Results: Between 2018 and 2021 pathological M1a decreased annually (51.9-46.3%), while M1c increased year-over-year (26.6-32.4%) and M1b stayed relatively the same (21.4-21.3%). These differences were significant on chi-squared analysis with a p value of < 0.001. Univariate analysis of the post hoc review between 2017 and 2020 revealed significant differences between stage 4a and 4c in terms of race (p value 0.018), carcinoembryonic antigen (CEA) at diagnosis (p value 0.037), CEA at recurrence (p value 0.012), presence of liver metastasis (p value 0.003), and referral pattern (p value 0.014). Multivariate analysis identified stage 4b as an independent predictor for hepatic metastasis (odds ratio; OR 4.69, p value 0.011).

Conclusions: A significant change in the distribution of colon cancer metastases has occurred at an institutional and national level over the past 3-5 years. Interdisciplinary treatment strategies will have to be modified accordingly.