de novo metastases in patients with primary colorectal cancer: a Surveillance, Epidemiology, and End Results analysis.

Purpose: Nearly one-quarter of colorectal cancer (CRC) cases present with de novo metastatic disease (stage IV) at diagnosis. Some metastatic sites confer poorer prognosis, and emerging data suggests that individuals from certain racial and ethnic populations may be at higher risk for de novo metastases.

Methods: We identified 181,083 CRC cases aged 20-84 between 2010 and 2020 in the Surveillance, Epidemiology, and End Results database. Two outcomes were analyzed: metastatic site (liver, lung, bone, brain) and metastatic pattern (liver only, lung only, liver and lung, other). We used logistic and multinomial logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CI) to examine the associations between race and ethnicity and metastatic site and metastatic pattern, respectively, among early-onset (age < 50), screen-eligible (age 50-74), and elderly populations (age 75-84).

Results: 43,054 de novo metastatic CRC cases were identified over the 10-year period. Liver was the most common metastatic site (80%). Non-Hispanic Black patients had higher odds of synchronous lung and liver metastases compared to non-Hispanic White (NHW) patients (early-onset patients: OR: 1.29, 95% CI 1.03-1.61; screen-eligible patients: OR:1.42, 95% CI 1.29-1.55; elderly patients: OR:1.66, 95% CI 1.34-2.05). Early-onset American Indian/Alaska Native patients were over twice as likely to present with lung metastases (OR: 2.10, 95% CI 1.11-3.98) compared to NHW patients.

Conclusions: Presentation and patterns of de novo metastatic CRC differed across populations and age groups. Characterizing de novo metastatic CRC provides a unique opportunity to study cancer spread in treatment-naïve individuals and to identify patients at greater risk of metastases associated with poorer prognosis.