Dihydropyrimidine dehydrogenase and fluoropyrimidines: a review of current dose adaptation practices and the impact on the future of personalized medicine using 5-fluorouracil

Chasing the personalized medicine dream through biomarker validation in colorectal cancer

Colorectal cancer (CRC) is a major health burden worldwide. The optimal approach to the diagnosis, management, and treatment of CRC involves multidisciplinary and integrated management practices. The field is rapidly changing because of recent advancements in delineating the molecular basis of tumorigenesis, introduction of targeted therapy, varied patient response to mainstay chemotherapeutics, biological drugs, and the effective combination regimes being used for treatment. Recent meta-analysis studies, which tend to establish few clinically useful predictor biomarkers, identify inconsistent results and limitations of the trials. Therefore, molecular pathological epidemiology discipline initiatives are promising. Here, we provide an overview of the potential of biomarker validation for personalized medicine by focusing largely on metastatic (m)CRC. We also highlight new candidate predictive and prognostic biomarkers.

Toxicity Associated with Capecitabine in Patients Suffering from Dihydropyrimidine Dehydrogenase Deficiency

Dihydropyrimidine dehydrogenase (DPD) is a metabolic enzyme that is crucial in 5-fluorouracil (5-FU) degradation. A deficiency in it is associated with the occurrence of adverse events following fluoropyrimidine-based therapies. We describe a case of toxicity grade 5 after the administration of capecitabine and oxaliplatin in a patient with stage III colorectal cancer and DPD congenital deficiency, which was identified later. Several polymorphisms have been associated with the global toxicity of 5-FU; however, genetic tests are low in sensitivity and therefore they cannot as yet be used as prescreening techniques in clinical practice.

[Quality assurance in head and neck medical oncology]

In medical oncology, how can we be sure that the right drug is being administered to the right patient at the right time? The implementation of quality assurance criteria is important in medical oncology, in order to ensure that the patient receives the best treatment safely. There is very little literature about quality assurance in medical oncology, as opposed to radiotherapy or cancer surgery. Quality assurance must cover the entire patient care process, from the diagnosis, to the therapeutic decision and drug distribution, including its selection, its preparation and its delivery to the patient (administration and dosage), and finally the potential side effects and their management. The dose-intensity respect is crucial, and its reduction can negatively affect overall survival rates, as shown in breast and testis cancers for example. In head and neck medical oncology, it is essential to respect the few well-standardized recommendations and the dose-intensity, in a population with numerous comorbidities. We will first review quality assurance criteria for the general medical oncology organization and then focus on head and neck medical oncology. We will then describe administration specificities of head and neck treatments (chemoradiation, radiation plus cetuximab, postoperative chemoradiation, induction and palliative chemotherapy) as well as their follow-up. Lastly, we will offer some recommendations to improve quality assurance in head and neck medical oncology.