Compared to cancers that occur in adults, cancers in children are rare. In developed countries, these comprise only 2% of all cancers while it is 3.0% in developing countries(1). The proportion of child-hood cancers relative to all cancers reported by Indian cancer registries varied from 2.1% to 6.2%. Studies of incidence pattern or cumulative risk provide a useful measure of health burden. No study on trends in incidence or risk in childhood cancer was so far reported from India. Some studies from cancer registries of Mumbai and Bangalore and some other studies(2-4) in India reported descriptive epidemiology of some childhood cancers. The present communication attempts report some highlights of temporal trends in childhood cancer cumulative risk from an ongoing study entitled "Exploration of National Cancer Registry Program (NCRP) data and its statistical modeling" of Institute of Cytology and Preventive Oncology, Indian Council of Medical Research (ICMR).

Age-specific cancer incidence rates of childhood period up to the age of 15 years are collected for the years 1982 to 2000 from NCRP reports(5) of ICMR. Cumulative risks are computed by using the formula: Cumulative risk = 100 × [1-exp (–cumulative rate/100)] where cumulative rate = [5 × å(ASpR) × 100]/100,000 and AspR is age specific incidence rate. The results obtained are as follows.

The cumulative risk ranges and significant linear trends in risks of childhood cancers during 1982-2000 for various cancer sites are depicted in Table I. The risks, in terms of one in number of children develop cancer, in different registries for male children are observed to be highest in Delhi with risk of one in 486 to lowest in Barshi with one in 1740. The risk for female children is highest in Chennai with one in 852 to lowest in Barshi with one in 3175. The risk for Luekemias of different types are found to be increasing during the study period in Mumbai and Bhopal while Luekemia unspecified observed a significant decline in Delhi among female children. Non Hodgkins Lymphoma risk is found to have increasing trends in Mumbai and Bhopal among males. There is a declining trend for risk of carcinomas of eye and Leukemia unspecified among male children of Mumbai and Delhi. Bone, Brain and Nervous system and Non Hodgkins Lymphoma risks are found to have increasing trends among females in different registries (Table I). The male to female ratio for magnitude of childhood cancers ranges from 1.1 to 2.5 in different registries. Childhood cancer risk among males is also higher as compared to females.

*Range for the years 1982 to 2000 for Bangalore, Mumbai and Chennai; 1988 to 2000 for the Barshi, Delhi and Bhopal.
Positive and negative trends are indicated by “Increase” and “decline” respectively. 
Blank cell (-) indicate no statistical significance observed in any registry for this childhood cancer site.
ICD: International Classification of Disease (Version no. 10)

Delhi reports highest magnitude of risks for males and Chennai for females in all cancers combined during childhood period. Significant increase in trends of childhood cancer risk detected for all sites combined in Chennai for males and in Mumbai for females. The trends observed may likely to give an insight into further understanding of childhood cancer etiology.

L Satyanarayana,
Smita Asthana,
Department of Epidemiology and Biostatistics,
Institute of Cytology and Preventive Oncology,
I-7, Sector-39, NOIDA, UP,
India.
E-mail: [email protected]