Introduction

The incidence and prevalence of cancer increases with age. In the year 2000, more than 50% of all malignancies occurred in the 12% of the population aged 65 and older. In the year 2030, the older population will account for 20% of the whole population and for 70% of all cancers. The number of older individuals receiving cytotoxic chemotherapy is progressively increasing, and it is legitimate to ask whether age may influence efficacy and toxicity of chemotherapy, especially the incidence of myelosuppression, which is the most common complication. In this chapter we will review the pharmacology of cytotoxic chemotherapy in the older aged person and explore methods to ameliorate the risk of toxicity.

Pharmacologic changes of aging

Pharmacokinetics

Most pharmacokinetic parameters may be influenced by age (Fig. 18.1). The absorption of nutrients decreases progressively due to reduced splanchnic circulation and absorbing surface, and reduced gastric motility and secretions. It is not clear whether bioavailability and efficacy of oral drugs may also be compromised. This is a practical issue as more oral cytotoxic agents are emerging. Oral agents are particularly suitable for the management of the older aged person, as they may be administered at home, and the dose may be adjusted on a daily basis.