Therapeutic progress--review VIII. Do the newer cytotoxic drugs represent a significant advance in the treatment of cancer?

The frequency of occurrence of rumours at different sites varies widely, but cancer of the lung, alimentary tract and breast account for at least 50% of all malignancy. The incidence rates of a number of types of tumour for males and females are shown in Table 2, together with the proportion that each represents of all cancer and the median age at presentation. An important characteristic of malignant tumours is the capacity for dissemination of tumour cells throughout the host. Such metastatic spread occurs early in the natural history of a large proportion of tumours, frequently before the primary lesion is clinically detectable. It is clear therefore, that in such cases treatment directed towards the primary tunour alone, such as surgical removal, cannot possibly achieve control of the disease. Some form of systemic therapy is necessary and this provides part of the rationale for the use of cytotoxic drugs, given orally or parenterally, which interfere with some facet of