Use of anti-EGFR agents among elderly patients with metastatic colorectal cancer (mCRC).

Abstract

657 Background: Limited data are available regarding the tolerance of older mCRC patients to anti-EGFR therapy. To evaluate the treatment patterns and tolerability of cetuximab/panitumumab in this patient population, we conducted a retrospective review of elderly patients treated with these agents at Fox Chase Cancer Center between 2004-2010. Methods: Patients ≥ age 65 with mCRC treated with cetuximab/panitumumab were included in the analysis. Patient demographics, disease characteristics, treatment drugs and duration, KRAS status and overall survival were recorded. Toxicity evaluation included review of common hematologic and non-hematologic toxicities seen with these agents. Results: 118 patients were included; 100 received cetuximab and 18 received panitumumab therapy. The majority of patients were male (59.3%) with colon cancer (82.2%) and stage IV disease at presentation (50.8%). The median age at treatment initiation was 73 yrs (range: 65-90). Median overall survival was 510 days, and the median time on treatment 73 days. Most patients were treated prior to the incorporation of routine KRAS testing thus, KRAS status was available for 35 patients (29.7%) with 14.2% KRAS mutant tumors. 66% of cetuximab and 45% of panitumumab treatments were given in combination with another agent. The overall incidence of any grade 3/4 non-hematologic toxicity was 36% (34% for single agent; 37.8% for combination therapy). Common grade 3/4 non-heme toxicities were: hypomagnesemia-16.9%, diarrhea-10.2%, and rash-9.3%. Diarrhea and hypomagnesemia were more common among patients receiving combination therapy. The overall incidence of any grade 3/4 hematologic toxicity was 15.2% (6.8% for single agent ; 20.3% for combination therapy). Anemia was the most common heme toxicity in both single and combination therapy. Advanced age at treatment initiation was associated with higher incidence of single agent therapy (p=0.0005, ANOVA statistics). Conclusions: Our data demonstrate that elderly patients with mCRC tolerate anti-EGFR therapy, with toxicity rates similar to those reported in large clinical trials with younger patient populations. Older mCRC patients can safely receive anti-EGFR treatment as part of their therapy.