# Follow-up intensity after colorectal cancer surgery in patients aged ≤ 50, 50–70 and > 70 years – an analysis within the COLOFOL randomised clinical trial

## TL;DR

This study found that more frequent follow-up after colorectal cancer surgery does not significantly reduce mortality or recurrence in patients aged 50 and younger.

## Contribution

The study provides evidence on the effectiveness of follow-up intensity in younger colorectal cancer patients, a growing demographic.

## Key findings

- High-frequency follow-up did not reduce 5-year overall mortality in patients aged ≤50.
- Cancer-specific recurrence was lower in the high-frequency group, but the difference was not statistically significant.
- No significant benefit of intensive follow-up was observed in younger patients with stage II-III CRC.

## Abstract

The incidence of colorectal cancer (CRC) is increasing in individuals aged < 50 years of age. This study aimed to examine whether high-frequency follow-up after CRC surgery reduces 5-year overall mortality, cancer-specific mortality and recurrence in patients with CRC aged ≤ 50 years.

The COLOFOL trial performed between 2006 and 2010 was used to analyse patients randomised to high-frequency (computed tomography [CT] of the abdomen and thorax and a carcinoembryonic antigen [CEA] test at 6, 12, 18, 24 and 36 months) versus low-frequency (CT and CEA at 12 and 36 months) follow-up after curative CRC surgery. Intention-to-treat and per-protocol analyses were performed to study the primary outcomes (5-year overall mortality and cancer-specific mortality) and the secondary outcome (CRC recurrence), comparing the age groups ≤ 50, 51–70 and > 70 years.

In total, 2,509 patients were included in the intention-to-treat analysis with 183, 1,714 and 612 patients aged ≤ 50, 51–70 and > 70 years, respectively. The 5-year overall mortality risk for patients aged ≤ 50 was 8.3% in the high-frequency group compared with 8.4% in the low-frequency group (risk difference 0.2% [95% CI, − 8.0; 8.3]). The cancer-specific mortality risk for patients aged ≤ 50 years was 7.1% in the high-frequency group compared with 7.4% in the low-frequency group (risk difference, 0.3% [95% CI, − 7.4; 8.0]). The cancer-specific recurrence risk for patients aged ≤ 50 years was 12.9% in the high-frequency group compared with 21.0% in the low-frequency group (risk difference 8.1% [95% CI, − 2.6; 18.7]).

Among individuals aged ≤ 50 years with stage II-III CRC, there was no reduction in overall mortality, cancer-specific mortality and cancer-specific recurrence with more intensive follow-up using CT and CEA.

The online version contains supplementary material available at 10.1007/s00384-026-05096-9.