Cetuximab-based therapy in elderly comorbid patients with metastatic colorectal cancer.

Background: Clinical trials under-represent patients (pts) >65 years. Non-interventional studies (NISs) help to evaluate therapies in daily practice. This NIS evaluates efficacy and safety of cetuximab in combination with chemotherapy in metastatic colorectal cancer (mCRC) pts aged >65 years vs ≤ 65 years.

Methods: A total of 657 pts were recruited into the NIS and analysed applying descriptive statistics and χ(2) or Fisher's exact test.

Results: A total of 309 and 305 pts aged ≤ 65 and >65 years, respectively, were documented; 80% showing a reduced ECOG status of 1-2 and 95% having received at least one palliative treatment. Cetuximab was combined with irinotecan according to approval status. Grade III/IV toxicities occurred in 20% of pts without any difference between age groups although the older pts had significantly more pre-existing comorbidities (P=0.001). A total of 64.2% of the pts developed skin rash, which was strongly related to response (P<0.0002) without any difference between age groups (P=0.34). The objective response rates were 37.9% for ages 18-65 years vs 35.4% for >65 years. Progression-free survival (PFS) did not differ between pts 18-65 years old (6.5 months) in comparison with pts >65 years (7.0 months). In a multivariate analysis only ECOG status had a negative impact on PFS (HR: 0,675; 95% Cl, 0.53-0.87; P=0.0019).

Conclusion: This NIS reports one of the largest mCRC collectives >65 years and reduced performance status. Cetuximab has a similar efficacy and safety profile for pts aged ≤ 65 and >65 years.