The Role of CYP450 Drug Metabolism in Precision Cardio-Oncology

As many novel cancer therapies continue to emerge, the field of Cardio-Oncology (or onco-cardiology) has become crucial to prevent, monitor and treat cancer therapy-related cardiovascular toxicity. Furthermore, given the narrow therapeutic window of most cancer therapies, drug-drug interactions are prevalent in the cancer population. Consequently, there is an increased risk of affecting drug efficacy or predisposing individual patients to adverse side effects. Here we review the role of cytochrome P450 (CYP450) enzymes in the field of Cardio-Oncology. We highlight the importance of cardiac medications in preventive Cardio-Oncology for high-risk patients or in the management of cardiotoxicities during or following cancer treatment. Common interactions between Oncology and Cardiology drugs are catalogued, emphasizing the impact of differential metabolism of each substrate drug on unpredictable drug bioavailability and consequent inter-individual variability in treatment response or development of cardiovascular toxicity. This inter-individual variability in bioavailability and subsequent response can be further enhanced by genomic variants in CYP450, or by modifications of CYP450 gene, RNA or protein expression or function in various 'omics' related to precision medicine. Thus, we advocate for an individualized approach to each patient by a multidisciplinary team with clinical pharmacists evaluating a treatment plan tailored to a practice of precision Cardio-Oncology. This review may increase awareness of these key concepts in the rapidly evolving field of Cardio-Oncology.

First-line treatment strategies for elderly patients with metastatic colorectal cancer

Colorectal cancer ranks third in incidence in both men and women after lung, breast and prostate cancer. The prevalence of colorectal cancer increases significantly with age, with 40% of patients in Europe being >75 years of age at the time of initial diagnosis. Furthermore, the number of elderly patients with colorectal cancer is expected to increase significantly over the next two decades. Treatment of advanced colorectal cancer has evolved dramatically over the last decade. Advances in surgery and chemotherapy are effective in prolonging time to disease progression and survival in patients with advanced colorectal cancer. For >40 years, fluorouracil has been the mainstay of chemotherapy for advanced colorectal cancer. Recently, however, newer cytotoxic chemotherapies and biological agents effective against colorectal cancer have been shown to improve overall survival in metastatic disease. Thus, a patient with metastatic colorectal cancer today has an expected median survival of 20 months compared with 10 months only a few years ago. There is evidence that elderly individuals derive as much survival benefit from standard chemotherapy approaches in metastatic colorectal cancer as younger patients. Unfortunately, most older patients who might benefit from chemotherapy are not offered this treatment, and the fraction who are not offered it increases with increasing age. Treatment decisions should not be made on the basis of age. Rather, they should be based on functional status, the presence of co-morbidities, and consideration of drug-specific toxicities that can be aggravated in older individuals because of decreased functional reserve. Although the elderly have been under-represented in clinical trials, studies also support the effectiveness of combination chemotherapy in elderly patients with advanced colorectal cancer. This article reviews current optimal first-line treatment strategies for elderly patients with metastatic colorectal cancer.

Guidelines for the management of the older cancer patient

Evaluation of: Balducci L, Cohen HJ, Enstrom PF et al.: Senior adult oncology clinical practice guidelines in oncology. J. Natl Compr. Cancer Center Netw. 3, 572–590 (2005). The management of older cancer patients with cytotoxic chemotherapy involves a new balance of benefits and risks, given the limited life expectancy and increased susceptibility to therapeutic complications of older individuals. The National Cancer Center Network has been issuing guidelines for the management of older cancer patients since 1999. This article reviews the basis of the most recent set of guidelines, issued in 2005. These include: some form of geriatric assessment for individuals aged 70 years and older to estimate their life expectancy and treatment tolerance; adjustment of the first dose of chemotherapy to glomerular filtration rate for individuals aged 65 years and older; prophylactic use of myelopoietic growth factors (e.g., filgrastim or pegfilgrastim) in patients aged 65 years and older treated with moderately toxic chemotherapy (of which cyclophosphamide, doxorubicin, vincristine and prednisone is the paradigm); maintainance of hemoglobin levels at approximately 12 gm/dl; and preferential use of drugs of low toxicity (e.g., capecitabine, pegylated liposomal doxorubicin, weekly taxanes, gemcitabine or navelbine).

Pharmacokinetic variability of anticancer agents

The translation of advances in cancer biology to drug discovery can be complicated by pharmacokinetic variation between individuals and within individuals, and this can result in unpredictable toxicity and variable antineoplastic effects. Previously unrecognized variables (such as genetic polymorphisms) are now known to have a significant impact on drug disposition. How can the pharmacokinetic variability of anticancer agents be reduced? This will require the understanding of correlations between pharmacokinetics and treatment outcomes, the identification of relevant patient parameters, mathematical modelling of individual and population pharmacokinetics, and the development of algorithms that will tailor doses to the individual patient.

[Treatment of cancer and hematological malignancy in elderly people: oncogeriatrics as a discipline for the future (Part I): geriatric evaluation and management of solid tumors]

PURPOSE

Fifty percent of cancer arise in people older than 65 year-old. Most clinical trials in cancer treatment are limited in patients younger than 65 year-old. We review literature describing particularity of cancer treatment in elderly patients.

CURRENT KNOWLEDGE AND KEY POINTS

Therapeutic decisions should be based on an estimation of the patient's life expectancy, and risks and benefits should be weighted up accordingly. Geriatric oncology is made of a geriatric evaluation of patient and of knowledge of clinical trial about elderly patients.

FUTURE PROSPECTS AND PROJECTS

We present in this issue the principle of geriatric evaluation and the results of recent clinical trial on elderly cancer patients.

Supportive care of the older cancer patient

Aging is associated with decreased functional reserve of multiple organ systems and with changes in the pharmacokinetics and pharmacodinamics of drugs. Older individuals express enhanced susceptibility to the complications of cytotoxic chemotherapy, especially to myleotoxicity, mucositis, cardiotoxicity and neurotoxicity. The management of older individuals with chemotherapy involves then prevention of these complications. General precautions include proper patient selection, based on the comprehensive geriatric assessment (CGA), dose adjustment for agents that are renally excreted to the patient creatinine clearance and maintenance of hemoglobin levels > or =12 g/dl. Filgrastim and pegfilgrastim proved effective in reducing by 50-75% the risk of neutropenic fever in older individuals treated with CHOP and CHOP-like chemotherapy and should be used for the prophilaxis of infections. When feasible, the oral agent capecitabine, should be used in lieu of intravenous fluorinated pyrimidines, to prevent mucositis. In patients at risk of cardiomyopathy from anthracyclines, dexrazoxane or liposomal compounds may be indicated. When toxicity is properly prevented, cytotoxic chemotherapy may be as effective in older individuals as it is in the younger ones.