[Chemotherapy for older cancer patients]

The population of Japan is gradually aging. Since cancer is mainly a disease of older persons, the incidence of malignancies of all types is expected to increase during the coming decades. Until recently, studies about responses to treatment and toxicity in the elderly patients have been very limited. Many clinical trials have excluded elderly patients with advanced cancer because of decreased tolerance to chemotherapy. In some older cancer patients, however, such exclusion may be inappropriate. Aging is a highly individualized process that cannot be defined by chronological landmarks. The great variation that exists between individual patients in terms of tolerance and responsiveness to chemotherapy seems to be closely related with biological age rather than chronological age of elderly persons. In general, the patterns of disease and stages at diagnosis are not the same for elderly and younger cancer patients. Because bone marrow cellularity diminishes with age, older patients appear to have decreased tolerance to certain anti-cancer agents. Therefore, administration of G-CSF combined with chemotherapy is necessary for elderly patients. A decline in the function of other vital organs also may reduce the efficiency of drug metabolism and excretion, resulting in greater toxic potential. Recently, the use of single-agent oral etoposide has been shown to be an effective palliative therapy for older patients with small-cell lung cancer. The combination of 5-FU with leucovorin has seemed to bring about a good response rate without any remarkable side effect for older patients with gastrointestinal cancer. The oral administration of 5'-DFUR has shown a remarkable prolongation of survival period and improvement of the cachectic status in older cancer patients. Future studies of palliative cancer chemotherapy will be needed to focus on the unique requirement of maintaining QOL in older patients.