Time trends in the registration of Hodgkin and non-Hodgkin lymphomas in Europe

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Abstract

Lymphoma incidence is reported to be increasing globally. If real, these trends can only be explained by an increasing exposure to risk(s) as yet unknown. There have been numerous coding and classification changes over time and greater access to ever more sensitive diagnostic tests. It is important to understand the consequences that these changes, coupled with general improvements in cancer registration, have had on observed temporal trends. Trends in the registration rates of both non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) in Europe are presented. Age-adjusted and age-specific rates are described in men and women in 13 European countries according to both period of diagnosis and year of birth. Age, period and cohort effects are modelled. Overall, there are increases in the numbers of NHL registrations made with a corresponding decrease in HL. In recent history, however, there is a suggestion that the rate of increase is less and stable.

Introduction

Over the last half-century, ubiquitous global increases in the number of cancer registrations of the most common lymphomas have been interpreted as signalling a genuine increase in incidence. The incidence of non-Hodgkin lymphoma (NHL) has been reported to have risen steadily in many countries for several decades.1, 2 In the US, the rates of NHL increased by 77% in black males and by 53% in white males and by 39% and 33% among black and white females, respectively, from the early-1980s to the mid-1990s.3 In seven European countries, the reported increase in NHL incidence was over 4% annually between 1985 and 1992, with a higher rate of increase in males than in females.4 Increases have also been confirmed in Asia (India, Japan, and Singapore), and in South America (Brazil and Colombia).5 Worldwide, about 287,400 new cases of NHL (about 60% in men) occurred globally in 2000,6 constituting approximately 3% of all cancers and the most frequently diagnosed haematopoietic malignancy.7

The interpretation of long-term trends in the incidence of lymphoma presents a number of difficulties. As well as a dynamic and evolving classification system, improvements in disease detection and cancer registration may have contributed to the temporal trends. NHL represents an extremely diverse group of malignancies. Changes in classification over time, including classification to Hodgkin’s lymphoma (HL) or other disease entities and vice versa, may account, according to one study, for about 10% of the overall increasing incidence rates.8

This study presents the observed trends in the registration rates of both NHL and HL in Europe. Age-adjusted and age-specific rates are described in men and women in 13 European countries according to both period of diagnosis and year of birth. The main aim is an evaluation of variations in NHL and HL registration rates in Europe, with an emphasis on determining the extent to which incidence trends are real, and to what extent the trends might be affected by changing classification.

Section snippets

Data sources

Registered incidence cases of NHL and HL (NHL: ICD-10 C82-C85, C96 HL: ICD-10 C81) and corresponding population data were obtained from the EUROCIM database9 by European cancer registry, year of diagnosis, sex, and for 14 five-year age groups (15–19, 20–24, …, 80–84). To ensure consistency in data quality with time, the analysis was restricted to cancer registries accepted in the last three volumes of Cancer Incidence in Five Continents.10, 11, 12 Regional registries were combined to obtain an

Statistical methods

Observed stratum-specific rates were calculated (per 100,00 person-years at risk) by age, sex and 5-year period of diagnosis for both HL and NHL, as were truncated age-standardised rates (European standard) for the age groups 15–44, 45–64 and 65–84. Synthetic birth cohorts spanning 10-year intervals were obtained for each population by subtracting the midpoints of 5-year age groups from the corresponding 5-year periods, with each resulting cohort overlapping by exactly five years. Age, period

Geographical and temporal variability across the 13 countries

There is a twofold variation in NHL rates for both men and women (Table 1), although rates are quite similar in the UK and the Nordic countries. There are also higher rates observed in men for both HL and NHL in all 13 countries; the M:F rate ratio varies by country from around 1.2 to 1.5, and this value is consistent for both types of lymphoma.

A scatter plot comparison of the average annual rate of change in incidence 1983–1997 is presented in Fig. 1a, Fig. 1b for all 13 countries (Table 1

Discussion

We have summarised trends in incidence from HL and NHL in 13 European countries for which the registry data are considered reliable over a sufficiently extended time period. For the UK (where the numbers were large) and the Nordic countries (where long-term data were available), the observed rates versus birth cohort and calendar time were also presented. Overall, there was a consistent increase in the estimated incidence of NHL in both sexes in all countries studied, alongside a decrease in HL.

Conflict of interest statement

None declared.

Acknowledgements

This study was part of the Comprehensive Cancer Monitoring Programme in Europe (CaMon) project funded by the European Commission, Agreement No. Sl2.327599 (2001CVG3–512). The following European cancer registries (Director in parentheses) are participating investigators, having contributed their incidence data, as well as their expertise in commenting on the final manuscript: Czech Republic – Czech National Cancer Registry, Prague (Dr. Jana Ajmová); Denmark – Danish Cancer Society, Copenhagen

References (32)

  • R. Cartwright et al.

    The rise in incidence of lymphomas in Europe 1985–1992

    Eur J Cancer

    (1999)
  • N.L. Harris et al.

    A revised European–American classification of lymphoid neoplasms: a proposal from the International Lymphoma Study Group

    Blood

    (1994)
  • H. Hjalgrim et al.

    Recent increase in the incidence of non-Hodgkin’s lymphoma among young men and women in Denmark

    Br J Cancer

    (1996)
  • R.J.Q. McNally et al.

    Leukemias and lymphomas: time trends in the UK, 1984–93

    Cancer Cause Control

    (1999)
  • F.D. Groves et al.

    Cancer surveillance series: non-Hodgkin’s lymphoma incidence by histologic subtype in the United States from 1978 through 1995

    J Natl Cancer Inst

    (2000)
  • S.S. Devesa et al.

    Non-Hodgkin’s lymphoma time trends: United States and international data

    Cancer Res

    (1992)
  • Ferlay J, Bray F, Pisani P, Parkin DM. GLOBOCAN 2002: cancer incidence, mortality and prevalence worldwide. IARC...
  • D.M. Parkin et al.

    Cancer burden in the year 2000. The global picture

    Eur J Cancer

    (2001)
  • P. Hartge et al.

    Quantification of the impact of known risk factors on time trends in non-Hodgkin’s lymphoma incidence

    Cancer Res

    (1992)
  • Ferlay J, Bray F, Sankila R, Parkin DM. EUROCIM. European network of cancer registries, Version 4.0. Lyon;...
  • D.M. Parkin et al.
    (1992)
  • D.M. Parkin et al.
    (1997)
  • D.M. Parkin et al.
    (2002)
  • D. Clayton et al.

    Models for temporal variation in cancer rates. I. Age–period and age–cohort models

    Stat Med

    (1987)
  • D. Clayton et al.

    Models for temporal variation in cancer rates. II. Age–period–cohort models

    Stat Med

    (1987)
  • T.R. Holford

    The estimation of age, period and cohort effects for vital rates

    Biometrics

    (1983)
  • Cited by (0)

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