Survival in stage IV colorectal cancer at diagnosis

Abstract

Background

It is well established that the primary tumor anatomic location of colorectal cancer (CRC) affects tumor biology and disease course, however, there exist few large-scale studies investigating oncologic outcomes of metastatic CRC at diagnosis based on anatomic location of primary tumor and metastasis.

Methods

A retrospective analysis of the National Cancer Database (NCDB) from 2016 to 2019 was performed identifying patients with metastatic colorectal cancer at diagnosis based on ICD-10 codes divided into left colon, right colon, and rectal primary. Patient demographic, tumor characteristic, treatment and outcomes data were obtained. The primary outcome measure was overall survival. Multivariable Cox regression was performed.

Results

Intra-abdominal metastases are the most common metastases for all primary tumor locations, however, rectal cancer more frequently metastasizes to extra-abdominal organs. Regardless of primary tumor location, lung metastasis has improved overall survival compared with liver or M1b/1c disease. Compared with left colon and rectal primary, metastatic right sided colon cancer had the worst median overall survival. Receipt of any surgical management, radiation, or oncologic treatment to primary site or metastasis was associated with improved overall survival.

Conclusions

These findings underpin the heterogeneity of colorectal cancer tumor biology and highlight the importance of understanding primary tumor location and metastasis location for appropriate patient education and prognostication. Appropriate patients had improved survival and low mortality with surgery.