Variation in survival of European children with acute lymphoblastic leukaemia, diagnosed in 1978-1992: the EUROCARE study

The aim of this study was to provide a comparative description of geographi cal variations and time trends in the population-based survival of European children with acute lymphoblastic leukaemia (ALL). Data on 13 344 newly di agnosed children (0-14 years) with ALL were included in the EUROCARE study and were collected were collected by 34 population-based cancer registries (four comprising only childhood malignancies), operating in 17 countries (f our in Scandinavia, two in Southern Europe, three in Eastern Europe, six in Continental Europe and two in the UK). Age-specific crude survival rates w ere estimated for boys and girls according to country for the period 1985-1 989 and in adjusted form to attain comparability. Overall pooled and weight ed rates were estimated as European standards. Children dead at diagnosis o r diagnosed only through a death certificate were excluded. Geographical va riation was also estimated by calculating the relative death rate with resp ect to the pooled overall European rate. After adjustment for age, gender a nd country, a Cox regression analysis was used to estimate time trends in s urvival. Survival was compared with that in the USA, Japan, Canada and Aust ralia. During 1985-1989, the 1-year survival rate varied from 99 to 79%, th e 5-year survival rate from over 80 to 56% (with the exception of Estonia; 34%; 95% confidence interval (CI) 20-52) among the various countries; the E uropean weighted means were 90 (95% CI 87-93) and 72% (95% CI 69-75), respe ctively. Survival was particularly favourable in (south) Sweden, Finland, G ermany and The Netherlands and rather unfavourable in Estonia and (surprisi ngly) France, where only 4% of its population was covered by the participat ing registries. Compared with the period 1978-1981, the hazard ratio for th e period 1986-1989 decreased to 0.59 (95% CI 0.54-0.64) and - in a smaller set of registries - to 0.49 (0.45-0.55) for 1990-1992, an annual decrease i n this rate of approximately 3.5%. During 1985-1989, the 5-year survival ra tes for European children were largely similar to those found in the USA, C anada and Australia, but markedly better than those in Japan. Higher surviv al rates were found for countries with 'good' access to centrally organised diagnostic and treatment facilities which stimulated 'agggressive' treatme nts according to a protocol. However, a subdivision according to risk profi les, e.g. according to the initial white blood cell count at diagnosis, cou ld not be made and this might have explained partially the geographical dif ferences in survival, because a positive association appeared between incid ence at age 1-4 years and 5-year survival in most countries. (C) 2001 Elsev ier Science Ltd. All rights reserved.