Chemotherapy and Targeted Agents in the Treatment of Elderly Patients with Metastatic Colorectal Cancer

Colorectal cancer (CRC) is one of the main causes of cancer death in the elderly. The older patients constitute a heterogeneous group in terms of functional status, comorbidities, and aging-related conditions. Therefore, therapeutic decisions need to be individualized. Additionally, a higher toxicity risk comes from the fact that pharmacokinetics and pharmacodynamics of the drugs as well as the tissue tolerance can be altered with aging. Although the chemotherapy efficacy in metastatic colorectal cancer (mCRC) is similar for older and young patients, more toxicity is presented in the elderly. While the mono-chemotherapy provides the same benefit for young and older patients, doublets front-line chemotherapy improves progression-free survival (PFS) but not overall survival (OS) in the elderly. Furthermore, the benefit of the addition of bevacizumab to chemotherapy in older patients has been shown in several clinical trials, while the clinical data for the benefit of anti-epidermal growth factor antibodies are scarcer. Immunocheckpoint inhibitors could be an appropriate option for patients with microsatellite instability (MSI) tumors. A prior geriatric assessment is required before deciding the type of treatment in order to offer the best therapeutic option.

Current role of antibody therapy in patients with metastatic colorectal cancer

In less than 10 years, the number and importance of non-surgical treatment modalities in patients with colorectal cancer (CRC) have increased dramatically, both in the adjuvant and the advanced settings. However, despite the improvement of cytotoxic therapy in CRC, many patients still develop progressive disease and unfortunately in patients with disease resistant to 5-fluorouracil/folinic acid, irinotecan and oxaliplatin, no effective cytotoxic therapy is known. The rapidly expanding knowledge in tumor biology has encouraged optimism for the possibility to find and target tumor-specific mechanisms and thereby increase both efficacy and tolerance. A great number of 'targeted drugs' are being tested in clinical trials and some of these new drugs, like bevacizumab, cetuximab and panitumumab, are available for routine use in health care. These new targeted drugs will expand the therapeutic arsenal in CRC to a great extent, but they will also add to the complexity of treatment of CRC. In this review, we summarize the current status of antibody therapy in patients with CRC.

Metastatic colorectal cancer

Metastatic colorectal cancer remains a public-health issue on a global scale. With development of a new generation of cytotoxic agents, survival has improved for patients with metastatic disease. How to maximize the benefit of chemotherapy with acceptable toxicity remains incompletely answered. Hepatic resection can provide a significant hope for long term survival, and a subset of patients might benefit from perioperative approaches. More recently, specific molecular processes have been targeted for therapeutic interventions, and encouraging results have been achieved using inhibitors of the Epidermal Growth Factor Receptor and the Vascular Endothelial Growth Factor.