New Directions in Cancer Treatment: An Overview

Abstract

In the first half of this century, effective cancer therapy was only available for patients with localized tumors amenable to surgery or to the evolving modality of irradiation. There were no available methods to eradicate disseminated disease, which is present at the time of diagnosis in some 30% of patients with invasive cancer. Many of the remaining percentage of patients will subsequently relapse with metastatic disease after loco-regional therapy. Since the 1950s there has been a dramatic broadening of the range of proven or potential methods of cancer therapy, which currently includes such disparate approaches as tumor bombardment with subatomic particles on the one hand, and attempts to manipulate biochemical pathways related to cell proliferation or differentiation on the other. Particulary gratifying is the demonstration that at least some patients with widely disseminated tumors are curable with modern approaches to therapy. In fact a high proportion of patients with certain cancers such as choriocarcinoma, testicular cancer, many lymphomas and leukemias, and a number of childhood neoplasms—at one time uniformly fatal—can now expect to be cured, although many other cancers remain refractory to treatment except when disease is localized. These promising results have their foundations in the numerous conceptual and technological advances of recent years. Some of these have had a direct impact on therapeutic strategies, such as the development of the linear accelerator and new cytotoxic drugs, but others have had a more indirect influence, including improvements in methods of conducting and evaluating clinical trials, vastly improved imaging techniques and advances in supportive care, particularly that of the febrile neutropenic patient.