Influence of comorbidity, age and performance status on treatment efficacy and safety of cetuximab plus irinotecan in irinotecan-refractory elderly patients with metastatic colorectal cancer.

We investigated the influence of comorbidity, Eastern Cooperative Oncology Group (ECOG) performance status and age on the efficacy and safety profile of cetuximab and irinotecan in elderly irinotecan-pretreated patients with mCRC. 497 patients with mCRC were entered in the database of this non-interventional study (NIS). Comorbid conditions were recorded. A total of 247 and 250 patients aged <65 and >65 years, respectively, with a median age of 66 y were documented; 78% of the patients showed a reduced ECOG status. Grade III/IV toxicities occurred in 18% of patients without any difference between age groups although older patients had more comorbidities with a higher Charlson Comorbidity Index (CCI) (p = 0.002). Skin rash was strongly related to response (p = 0.006). Age, line of therapy, ECOG, gender and CCI had no influence on response. The objective response rates were similar: 38.1% for age <65 years versus 36.4% for age >65 years (p = 0.57). Progression-free survival (PFS) did not differ between patients 18-65 years (6.0 months) and patients >65 years (6.2 months; p = 0.99). Only PS had a negative impact on PFS (hazard ratio (HR): 0,499; 95% confidence interval (CI) 0.34-0.72; p=0.002), whereas the presence of skin toxicity (grade>1) influenced PFS and response rate (RR) positively (HR: 2.04; 95% CI, 1.6-2.6; p<0.001). Only PS and age had a negative influence on PFS irrespective of CCI or age. There were no significant differences in response rate and safety profile for elderly patients when treated with cetuximab and irinotecan. Comorbidities and age had no influence on efficacy or toxicity.