Childhood cancer survival in Europe.

BACKGROUND: EUROCARE-3 collected data from 45 population-based cancer registries in 20 countries on 24 620 European children aged from 0 to 14 years diagnosed with malignancy in the period 1990-1994. METHODS: Five-year survival between countries was compared for all malignancies and for the major diagnostic categories, adjusting for age, and estimated average European survival weighting for differences in childhood populations. RESULTS: For all cancers combined, survival variation was large (45% in Estonia to 90% in Iceland), and was generally low (60-70%) in eastern Europe and high (> or =75%) in Switzerland, Germany and the Nordic countries (except Denmark). The Nordic countries had the highest survival for four of the seven major tumour types: nephroblastoma (92%), acute lymphoid leukaemia (85%), CNS tumours (73%) and acute non-lymphocytic leukaemia (62%). The eastern countries had lowest survival: 89% for Hodgkin's disease, 71% for nephroblastoma, 68% for acute lymphoid leukaemia, 61% for non-Hodgkin's lymphoma, 57% for central nervous system (CNS) tumours and 29% for acute non-lymphocytic leukaemia. CONCLUSIONS: The Nordic countries represent a survival gold standard to which other countries can aspire. Since most childhood cancers respond well to treatment, survival differences are attributable to differences in access (including referral and timely diagnosis) and use of modern treatments; however, the obstacles to access and application of standard treatments probably vary markedly with country.

Cancer prevalence in Northern Europe: the EUROPREVAL study.

BACKGROUND: Information on cancer prevalence is of importance for health planning and resource allocation, but is not always available. In order to obtain such data in a comparable way a systematic evaluation of cancer prevalence in Europe was undertaken within the EUROPREVAL project. PATIENTS AND METHODS: Standardised data were collected from 38 population-based registries on almost 3 million cancer patients diagnosed between 1970 and 1992. The prevalence of 11 specific cancer types was estimated at the index date of 31 December 1992. This study deals with the northern countries Denmark, Estonia, Finland, Iceland and Sweden. RESULTS: There were large differences between these countries, Sweden having the highest prevalence rate of 3050 per 100 000 and Estonia the lowest, 1339 per 100 000. This difference is mainly due to a high proportion of cancers with favourable prognosis such as breast cancer, prostate cancer and melanoma, better survival and longer life expectancy in Sweden, whereas Estonia has a higher proportion of stomach and lung cancer with poor prognosis, worse survival and much shorter life expectancy, especially for males. For most tumour types, the Nordic countries did better than Estonia. There are indications that cancer patients in Estonia, as well as in Denmark, have a more advanced stage at diagnosis and that the Estonian health-care system is less efficient. CONCLUSIONS: Despite many similarities and a common historical background, the northern countries in Europe that participated in the EUROPREVAL study display quite different cancer patterns and prevalence. Reasons for these variations are discussed.

Measuring cancer prevalence in Europe: the EUROPREVAL project.

Cancer prevalence is the proportion of individuals in a population who at some stage during their lifetime have been diagnosed with cancer, irrespective of the date of diagnosis. Cancer prevalence statistics have generally been provided by a limited number of well established cancer registries that have been in existence for several decades. The advent of systematic follow-up of life status of incident cases and the availability of new statistical methodologies, now makes it possible for registries established during the 1970s or 1980s to provide prevalence data. The main problems encountered in the estimation of prevalence are the inclusion of: (i) cases lost to follow-up; (ii) cases known only from their death certificate; (iii) cases diagnosed before the start of registration; and (iv) the treatment of multiple tumours and migrations. The main aim of this paper was to review these problems and discuss, through the experience gained with EUROPREVAL, how they can be overcome. A method is presented for the calculation of prevalence of all cancers combined in the populations covered by the 45 cancer registries participating in EUROPREVAL. Prevalence of cancer is estimated to be 2% on average, with the highest values (3%) in Sweden and the lowest in Eastern Europe, with a minimum of approximately 1% in Poland.

Childhood malignancies in the EUROCARE study: the database and the methods of survival analysis.

This paper describes the database of children with cancer in the EUROCARE study and the methodology used to analyse and report survival. This is the first systematic evaluation of survival after childhood cancer on a large scale in Europe: approximately 45,000 cases were included, diagnosed between 1978 and 1992 (34,814 cases diagnosed in 1978--1989 and an additional set of 9495 cases diagnosed in 1990--1992) and followed-up until 1995. Data were provided from 34 population-based registries (four specialised for childhood cancer registrations and one specialised registry for childhood leukaemia) in 17 countries of Europe (where there was national coverage in 10 countries). Quality of the data was fairly good, given the general differences among the countries and their health systems, thereby allowing for comparisons between them. Among cases diagnosed in 1978--1989, overall 2.0% were lost to follow-up, 91.8% were microscopically diagnosed and 93.4% of alive cases had at least 5 years of observation. Survival proportions (observed survival) were calculated for each of the countries involved, by age group (0, 1--4, 5--9, 10--14 years), gender, different time periods and selected diagnostic groups. Age-standardised cumulative survival rates and European averages (weighted and pooled) were also computed. Cox regression models were used to evaluate geographical and temporal differences. The EUROCARE database represents a unique source of information on survival of childhood cancer patients in Europe, intercountry differences and time trends in survival.

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 geographical variations and time trends in the population-based survival of European children with acute lymphoblastic leukaemia (ALL). Data on 13344 newly diagnosed 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 (four in Scandinavia, two in Southern Europe, three in Eastern Europe, six in Continental Europe and two in the UK). Age-specific crude survival rates were estimated for boys and girls according to country for the period 1985--1989 and in adjusted form to attain comparability. Overall pooled and weighted rates were estimated as European standards. Children dead at diagnosis or diagnosed only through a death certificate were excluded. Geographical variation was also estimated by calculating the relative death rate with respect to the pooled overall European rate. After adjustment for age, gender and country, a Cox regression analysis was used to estimate time trends in survival. Survival was compared with that in the USA, Japan, Canada and Australia. During 1985--1989, the 1-year survival rate varied from 99 to 79%, the 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 European weighted means were 90 (95% CI 87--93) and 72% (95% CI 69--75), respectively. Survival was particularly favourable in (south) Sweden, Finland, Germany and The Netherlands and rather unfavourable in Estonia and (surprisingly) France, where only 4% of its population was covered by the participating registries. Compared with the period 1978--1981, the hazard ratio for the 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 in this rate of approximately 3.5%. During 1985--1989, the 5-year survival rates for European children were largely similar to those found in the USA, Canada and Australia, but markedly better than those in Japan. Higher survival rates were found for countries with 'good' access to centrally organised diagnostic and treatment facilities which stimulated 'aggressive' treatments according to a protocol. However, a subdivision according to risk profiles, e.g. according to the initial white blood cell count at diagnosis, could not be made and this might have explained partially the geographical differences in survival, because a positive association appeared between incidence at age 1--4 years and 5-year survival in most countries.

Survival from acute non-lymphocytic leukaemia (ANLL) and chronic myeloid leukaemia (CML) in European children since 1978: a population-based study.

We used data supplied by population-based cancer registries, collected and quality controlled using a common protocol, to analyse survival from acute non-lymphocytic leukaemia (ANLL) and chronic myeloid leukaemia (CML) among children in 17 European countries. Variations in survival in relation to age, country, histologic subtype and period of diagnosis (1978--1992) were examined. These are rare malignancies and survival can be studied reliably only by examination of data from a very large population (in this case EUROCARE). 5 years after diagnosis, overall survival was 44% (95% CI 33--55) for CML and 37% (95% CI 32--43) for ANLL. For both types of leukaemia, survival was slightly better for girls and worse in children under 5 years of age. Consistent with clinical literature, the ANLL subtypes with poorer prognosis were monocytic, megakaryocytic and erythroleukaemia. For ANLL, 5-year survival was better in Finland, the UK, The Netherlands and Germany (> or =40%); for CML, 5-year survival was highest in Italy, although the 95% CI were wide. The risk of death from ANLL and CML fell by 7% per year and 5% per year, respectively, after adjustment for age, gender and country. Since these rare childhood malignancies were virtually untreatable until 1970, these are very welcome trends.

Survival of children with liver tumours in Europe 1978--1989.

Hepatic tumours are rare in childhood. Within the frame of the EUROCARE II study, a total of 328 liver tumours in patients aged 0--14 years were reported during the period 1978--1989. The childhood cancer registries in UK and Germany contributed approximately a third of the cases each. Hepatoblastoma accounted for 71% of cases. The 5-year survival was 36% 95% confidence interval (CI) 28--46%, with no significant difference between the genders. Patients aged 10--14 years did worse, especially boys. Survival improved significantly during the study period. Survival in hepatocellular carcinoma was lower, 20% (95% CI 6--52%), and showed no improvement during the study period.

Survival of children with bone sarcoma in Europe since 1978: results from the EUROCARE study.

Malignant bone tumours in children are rare, accounting for approximately 5% of all childhood cancers in European countries. In the EUROCARE childhood cancer study, there were 1785 registrations from 16 countries for bone cancers in patients aged 0--14 years during 1978--1989. Of this total, almost three-quarters were contributed by childhood cancer registries in Germany and the UK. Estimated 5-year survival rates were 52% for osteosarcoma and 50% for Ewing's sarcoma over the entire study period and 60% for both diagnostic groups in 1985--1989. For osteosarcoma, survival rates increased substantially until about 1985, but then showed no further improvement. For Ewing's sarcoma, there was a steady increase throughout the study period. Improvements in survival which had previously been reported from individual countries and in clinical series are confirmed as having taken place throughout much of Europe on a population basis.

Survival of children with soft-tissue sarcoma in Europe since 1978: results from the EUROCARE study.

Soft-tissue sarcomas account for 5--8% of all childhood cancers in European countries. In the EUROCARE childhood cancer study, there were 2163 registrations from 17 countries for soft-tissue sarcomas in patients aged 0--14 years during 1978--1989. Of this total, three-quarters were contributed by childhood cancer registries in Germany and the UK. Age-standardised 5-year survival rates of children diagnosed during 1985--1989 were 65% (95% confidence interval (CI) 56--72) for rhabdomyosarcoma, 68% (95% CI 58--77) for fibrosarcoma, 78% (95% CI: 64--87) for other specified soft-tissue sarcomas except Kaposi's and 51% (95% CI 37--65) for 'unspecified' soft-tissue sarcomas. Survival rates increased steadily throughout the 12-year study period for all soft-tissue sarcomas combined, but the increase took place predominantly in the early 1980s for rhabdomyosarcoma. Improvements in survival which had previously been reported from individual countries and in clinical series are confirmed as having taken place throughout much of Europe on a population basis. In a supplementary analysis, there was little indication of a further improvement during 1990--1992.

Correcting the completeness bias of observed prevalence.

AIMS AND BACKGROUND: The cancer prevalence in given areas can be estimated on the basis of data supplied by cancer registries. As the obtained estimate of prevalence depends on the length of the cancer registry's observation period, it is generally lower than the total prevalence in the considered area. In the present work we propose a method to calculate a correction factor of this bias in order to obtain an approximation to the total prevalence. METHODS & STUDY DESIGN: The method is based on the relationship between relative survival and incidence by age for a specific cancer site. RESULTS AND CONCLUSIONS: We provide values of the correction factor, the completeness index R, relative to the most important cancer sites, for specific ages and periods of observation of the cancer registries in Italy. In addition, we provide indications for extended use of the index when substantial variations from the basic pattern of relative survival are observed in practical situations. Furthermore, we give helpful suggestions to obtain approximate values of the correction factor to be used for ages and periods of observation that are intermediate between the ones presented in this paper.