A SINGLE INSTITUTIONAL EXPERIENCE WITH CETUXIMAB IN METASTATIC COLORECTAL CANCER

Abstract

Introduction: Cetuximab is an IgG1 monoclonal antibody (mAb) against epidermal growth factor receptor (EGFR) with limited efficacy in the subset of patients with RAS wild type metastatic colorectal cancer (mCRC).

Purpose of this study is to present our Institution’s experience in patients with wild type metastatic CRC treated with Cetuximab.

Methods: We collected data for 18 patients with wild-type RAS mCRC. Patients received Cetuximab (500mg/m2) in combination with oxaliplatin and irinotecan-based chemotherapy. The treatment has been continued until unacceptable toxicity or disease progression (PD). Tumour response has been evaluated every 12 weeks using Response Evaluation Criteria in Solid Tumors (RECIST 1.1) and toxicity was assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0.

Results: Eighteen patients with median age 55 years (range 41-67 y) were identified. Most patients were in good ECOG Performance Status (0-2). The primary location of cancer was the rectum (11 patients), and colon (7 patients). The most common metastatic sites were liver and lungs with more than 50% of patients (72.2%) having 2 or 3 metastatic sites.

Most patients (55.56%) received ≥ 1 prior lines of chemotherapy and 44.44% of patients received Cetuximab as 1st line treatment. Six patients (33.33%) received it in combination with Oxaliplatin and 12 patients (66.67%) received it in combination with Irinothecan-based chemotherapy. In the majority of cases (77.77%) good response to treatment was reported (stable disease in 44.44% (8) and partial response in 33.33% (6)).

In regards to toxicity, rash grade 1 was the most common adverse effect. Ocular toxicity (conjunctivitis) was reported in only one patient. The 12-month survival rate was 94% and the 24-month survival rate was 46%.

Conclusion: Over the last decades, the incorporation of novel agents in the management of mCRC is associated with improvement in survival. Anti EGFR mab is an effective and well-tolerated treatment option in RAS wt mCRC. Nowadays, molecular profiling with the identification of prognostic and predictive biomarkers provides a personalized treatment approach, with the potential of improved treatment efficacy. To asses value of adding Cetuximab to mCRC treatment, longer follow-up is needed.