Incidence and survival of childhood cancers in Singapore, 1968-1997: A population-based study

Abstract

Objective: To describe the incidence and survival rates of childhood cancers from 1968 to 1997 in Singapore, and identify the trends of incidence and survival over the three decades to provide clues to the environmental reasons of the temporal patterns. Methods: Data of cancers on patients diagnosed between 1968 and 1997 at the ages of 0a??14 years was retrieved from the Singapore cancer registry and death registry. All childhood cancers were classified into 12 diagnostic groups according to the International Classification of Childhood Cancer based on the histology of the cancer. The trends and patterns of age-standardized incidence rates (ASR) of 2129 subjects were calculated by childhood cancer type, age and ten year period for both genders. Observed (OSR) and relative survival rates (RSR) of 2066 cases were estimated by age, sex and selected cancer type. Results: The overall ASR for childhood cancers was 109.3 per million children per year. Leukemia was the most common childhood cancers (38.2%), followed by brain and spinal neoplasms (14.2%), and lymphoma (9.8%). Increasing trends of incidence were observed in most childhood cancers except for Non-Hodgkina??s lymphoma (NHL), renal tumors and malignant bone tumors. The survival for all cancers was markedly improved from 30-35% in the period 1968-77 to 55-60% in the period 1988-97. The survivals, especially for patients with leukemia, NHL, renal tumors, were improved more than 20% over the three decades., however, the survivals for some diagnostic groups in Singapore were lower when compared with those reported in USA, except that for NHL. Conclusion: The incidences of childhood cancers in Singapore were comparable with those in western countries. The observed increase in incidence somehow resulted from changes in detection and environmental factors. The survivals of childhood cancer patients have been markedly improved in Singapore, but this finding suggested that the introduction and practice of chemotherapy was insufficient.