Phase I and II trials in pediatric cancer patients: a rationale

Abstract

Childhood malignancies are relatively rare diseases. In the United States, approximately 7,000 new cases of cancer are seen annually in children [1], compared to over 900,000 new cases in adults [2]. Nevertheless, these diseases attract clinical interest far in excess of that predicted by their relative rarity. This is, of course, in large part due to the occurrence of these diseases in the young of our species. Beyond this, however, pediatric oncologists and related scientists are increasingly aware of the unique opportunities to understand the process of malignancy provided by the study of these patients, opportunities afforded by the distinctive characteristics associated with cancer in the young. These characteristics include a generally large kinetic growth fraction and rapid growth [3], origin in mesodermal rather than ectodermal tissue, and occurrence in a growing organism which is continually altering on its way toward biologic maturity, with all the attendant physiologic events associated with development. The increased responsiveness of childhood tumors to current therapeutic strategies is well documented [4], and is one of the major reasons for optimism in the eventual control of malignancy in humans.