Individualizing chemotherapeutic treatment of colorectal cancer

Chemotherapy induced diarrhea

Purpose: To provide a current review of the literature related to chemotherapy induced diarrhea (CID), including clinical assessment, recommended management guidelines and investigational pharmacological approaches for the prevention and treatment of CID.

Data sources: A search of MEDLINE, PubMed, EMBASE, Cochrane Library, International Pharmaceutical Abstracts, and Web of Science (1996—2006) databases was conducted using terms such as: chemotherapy, diarrhea, diarrhoea, and irinotecan. Appropriate references from selected articles were also used. The search engine, Google, provided further access to information.

Data extraction: The retrieved literature was reviewed to include all articles pertaining to the pathophysiology, assessment and management of CID.

Data synthesis: Diarrhea is a debilitating and potentially life-threatening side effect associated with many chemotherapeutic agents. Despite the high incidence and severity of CID, it is often under recognized and poorly managed. A multidisciplinary panel recently updated recommended practice guidelines for the assessment and management of CID. Prompt and aggressive intervention is important in order to minimize the negative consequences of CID, such as dehydration, which may cause interruptions in optimal clinical outcomes or may lead to life-threatening sequelae. Further investigation into the pathophysiology of CID may allow for more directed approaches in the prophylaxis and treatment of CID. J Oncol Pharm Practice (2007) 13: 181—198.

New therapeutic directions for advanced pancreatic cancer: targeting the epidermal growth factor and vascular endothelial growth factor pathways

In advanced pancreatic cancer, single-agent gemcitabine became the standard therapy approximately 10 years ago. Subsequently, combinations of gemcitabine with fluorouracil, cisplatin, irinotecan, oxaliplatin, or pemetrexed produced no clear survival benefit. Among the newer approaches, targeting human epidermal growth factor receptor (HER-1/EGFR) shows promise. The U.S. Food and Drug Administration recently approved erlotinib (a HER-1/EGFR tyrosine kinase inhibitor) combined with gemcitabine for the first-line treatment of advanced pancreatic cancer. This combination showed a statistically significant survival benefit over gemcitabine alone in locally advanced or metastatic disease (the median overall survival time was 6.24 months versus 5.91 months; hazard ratio, 0.82; p = .038); however, the clinical significance of this survival difference has been questioned. Additionally, a large phase III trial where the addition of cetuximab (an anti-HER-1/EGFR monoclonal antibody [mAb]) to gemcitabine failed to result in a longer overall survival time than with gemcitabine alone has been reported. Targeting vascular endothelial growth factor (VEGF) with bevacizumab (a recombinant, humanized IgG1 mAb that binds to VEGF) in combination with gemcitabine was investigated in a phase II trial, with promising outcomes that were unfortunately not supported by a subsequent phase III study. While the future treatment of pancreatic cancer may be influenced by the potential of certain biomarkers to predict better response to molecular-targeted therapies, allowing individualization of patient therapy, there are currently no clear candidates, and this remains an interesting area for further investigation.

Epidermal growth factor receptor (EGFR) polymorphisms and survival in head and neck cancer patients

EGFR overexpression has been implicated in the development of head and neck squamous cell carcinoma (HNSCC). This study evaluates the prognostic ability of four polymorphisms in EGFR gene for patients diagnosed with HNSCC and treated with chemoradiation. EGFR polymorphisms in the promoter region were not associated with clinical or pathological characteristics. In relation to R497K polymorphism, patients with the Arg/Arg genotype showed the highest risk of disease-specificity mortality and none of the patients with the Lys/Lys genotype died throughout the follow-up period of the study. Patients with (CA)(n) repeats <17 in both alleles tended toward inferior overall survival compared with those with (CA)(n) repeats > or = 17 in both alleles (p=0.07). Moreover, the distribution of patients with any (CA)(n) repeats > or = 17 and both alleles <17 was statistically different across patients who were recorded as having partial response or no response to therapy (p=0.034). Combination analysis of both polymorphisms, (CA)(n) repeats and R497K, suggests that these polymorphisms may be associated with clinical outcome in patients treated with chemoradiation.