Tumour deposits and oncological outcomes in early-onset colorectal cancer patients—a retrospective nationwide cohort study

Abstract

The incidence of early-onset colorectal cancer (EOCRC) is rising. Tumour deposits (TDs) are an independent negative prognostic factor in colorectal cancer (CRC), but their prognostic impact in EOCRC has not been studied. This study aimed to investigate the prognostic effect of TDs on EOCRC patients. Patients who underwent surgery for CRC between 2011–2014 and 2016–2019 were extracted from the Swedish Colorectal Cancer Registry. Patients were stratified by age (EOCRC (<50 years) versus late-onset CRC (LOCRC, ≥50 years)) and TD status. Kaplan-Meier curves and multivariable Cox regression analyses were used to assess the prognostic effect of TDs in EOCRC patients on overall survival (OS) and distant metastasis (DM) adjusted for sex, number of positive lymph nodes, and neoadjuvant therapy. Of 26 970 included patients, 12.3% were TD-positive and 4.8% EOCRC. TD-positive EOCRC patients had worse 5-year OS (75.8 versus 92.4%, P < 0.001) and higher 5-year risk of DM (40.6 versus 14.7%, P < 0.001) compared to TD-negative EOCRC patients. In multivariable analysis, TDs were independently associated with increased risk of DM in both EOCRC (HR 1.55, 95% c.i. 1.16–2.07) and LOCRC (HR 1.65, 95% c.i. 1.49–1.84). However, while TD positivity in LOCRC patients was associated with worse OS (HR 1.45, 95% c.i. 1.33–1.58), no independent association with OS was observed for TD-positive EOCRC (HR 0.84, 95% c.i. 0.60–1.18). TDs are associated with an increased risk of distant metastasis in EOCRC but not with overall survival after adjustment. These findings support the prognostic relevance of TDs in EOCRC, particularly for metastatic risk.