PM7 - Colon Cancer with Peritoneal Metastasis: a National Cancer Database Analysis of Treatment Sequencing Trends

Background: The role of cytoreductive surgery in treating colon cancer with peritoneal metastasis (PM) has become less controversial, but treatment sequence remains debated. We aimed to examine treatment sequencing trends and predictors of treatment using the National Cancer Database (NCDB).

Methods: The NCDB was queried to identify colon cancer patients with PM between 2010-2015. Clinical stage IV colon cancers with known primary site and without bone, brain, liver or lung metastasis were included. Cochran-Armitage tests were used for the sequencing trend analyses, logistic regression models for multivariable analysis.

Results: 3798 patients with PM were identified; 63%, 21%, and 15% received surgery, chemotherapy, or no treatment as first approach, respectively. Of those who received both surgery and chemotherapy, <10% received chemotherapy in the neoadjuvant setting. Over the period, a significant downward trend was observed for patients receiving surgery and adjuvant chemotherapy (46% to 26%) and an upward trend for no treatment (14% to 21%) and chemotherapy only (13% to 20%). On multivariable analysis, facility type, age, sex, insurance, primary site, histology and year of diagnosis were significant. Notably, community and integrated cancer programs were at increased odds of performing surgery first compared to administering chemotherapy. Patients with age ≥ 70 or public insurance were less likely to receive any treatment.

Conclusion: While there was an overall trend towards utilizing palliative treatment approaches, only a small number of patients received neoadjuvant chemotherapy. Age, facility, and insurance were the major determinants of treatment received, possibly suggesting underlying healthcare disparities.