593P - Treatment response and survival of patients with early onset colorectal cancer in the Netherlands

Background

The incidence of patients with sporadic early-onset colorectal cancer (eoCRC) (<50 years) is increasing. Despite likely different tumor biology and suggestions of more aggressive disease, treatment is similar to older patients. The aim of this study was to investigate treatment response and survival in patients with eoCRC compared to matched data of older-onset (oo)CRC.

Methods

Clinicopathological data of all mismatch repair proficient (pMMR) eoCRC patients diagnosed between 2016 and 2022 were requested from the Netherlands Cancer Registry. Additionally matched data from patients between 50-70 and ≥70 years were requested. Matching was performed on tumor stage, RAS/BRAF mutation status, tumor sidedness and systemic therapy. To compare groups, two sided X² tests and Fisher’s exact tests were used. Overall survival (OS) and progression free survival (PFS) was analyzed with Kaplan Meier and median survival times were compared with the log-rank test (R software). P-values < 0.05 were considered significant.

Results

In total 3412 patients with eoCRC (mean 43 years) and matched data from 3143 and 2624 ooCRC patients aged 50-70 (mean 60 years) and ≥70 (mean 75 years), respectively, were retrieved. The 5-year OS was 67%, 65% and 54% for patients <50, 50-70 and ≥70 years of age, respectively (p < 0.001). Median OS for patients with metastatic disease at diagnosis was 22, 22 and 19 months for patients <50, 50-70 and ≥70 years (p = 0.0013). Of eoCRC patients, 46% had a RAS mutation and 10% a BRAF mutation. Best response to first line treatment was 2% complete remission, 63% partial remission, 14% stable disease, 1% mixed response and 20% progressive disease (ns). Median PFS to first line treatment was 4 months for eoCRC patients and 5 months for ooCRC (ns). In total, 89%, 90% and 80% received oxaliplatin (ns), and 24%, 16% and 6% received irinotecan (p < 0.001) respectively. Anti-EGFR treatment was given in 21%, 9% and 3% of left-sided RAS/BRAF wildtype CRC patients, respectively (p = 0.035).

Conclusions

EoCRC patients have similar response rates and PFS to first line systemic treatment compared to matched ooCRC patients. Although eoCRC patients more often received irinotecan and anti-EGFR therapy compared to ooCRC, the OS for eoCRC was similar to patients aged 50-70.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

ZonMw.

Disclosure

L. Vermeulen: Other, Personal, Full or part-time Employment, Employee: Genentech Inc; Other, Personal, Stocks/Shares, Shareholder: Roche; Financial Interests, Speaker, Consultant, Advisor, These had no relation to the content of this abstract: Bayer, MSD, Genentech, Servier, Pierre Fabre. All other authors have declared no conflicts of interest.