Journal of the National Cancer Institute Advance Access originally published online on October 26, 2009
JNCI Journal of the National Cancer Institute 2009 101(22):1584-1591; doi:10.1093/jnci/djp358
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ARTICLES |
Recent Changes in Breast Cancer Incidence in Spain, 1980–2004
Affiliations of authors: Área de Epidemiología Ambiental y Cáncer, Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Madrid, Spain (MP, RP-B, EV, GL-A); CIBER Epidemiología y Salud Pública, Spain (MP, RP-B, EA, M-JS-P, M-DC, NL, EV, M-EPdeR, CN, GL-A, CMz); Registro de Cáncer de Navarra, Instituto de Salud Pública de Navarra, Pamplona, Spain (EA, M-EPdeR); Registro de Cáncer del Principado de Asturias, Dirección General de Salud Pública y Participación, Consejería de Salud y Servicios Sanitarios, Oviedo, Spain (MA, SG); Registro de Cáncer de Zaragoza, Departamento de Salud Pública, Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain (CMs); Registre de Càncer de Tarragona, Fundació Lliga per a la Investigació i Prevenció del Càncer, Tarragona, Spain (JG, JB); Registro de Cáncer de Granada, Escuela Andaluza de Salud Pública, Granada, Spain (M-JS-P, CMz); Registro de Cáncer de Murcia, Departamento de Epidemiología, Consejería de Sanidad, Murcia, Spain (M-DC, CN); Subdirección de Salud Pública de Gipuzkoa, Gobierno Vasco, San Sebastián, Spain (NL); Registro de Cáncer del País Vasco, Subdirección de Sanidad de Araba, Gobierno Vasco, Vitoria, Spain (RM-C); Subdirección de Sanidad de Araba, Gobierno Vasco, Vitoria, Spain (M-CT); Unitat d'Epidemiologia i Registre de Càncer de Girona, Pla Director d'Oncologia, Departament de Salut, Girona, Spain (RM-G, AI); Registro de Cáncer de Albacete, Consejería de Salud y Bienestar Social, Albacete, Spain (AM); Registre de Càncer de Mallorca, Servei d'Epidemiologia, Direcció General de Salud Pública i Participació, Palma de Mallorca, Spain (IG); Registro de Cáncer de Canarias, Dirección General de Salud Pública, Las Palmas, Spain (M-DR-M); Registro de Cáncer de Cuenca, Consejería de Salud y Bienestar Social, Cuenca, Spain (RJ); Registre de Càncer de Castelló, Direcciò General de Salud Pública, Castelló, Spain (AT-R); Registro de Cáncer de La Rioja, Servicio de Epidemiología y Prevención Sanitaria, Logroño, Spain (JP); Universidad de Zaragoza, Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain (M-JR); Departamento de Salud Pública de Bizkaia, Gobierno Vasco, Bilbao, Spain (EH)
Correspondence to: Marina Pollán, MD, PhD, Área de Epidemiología Ambiental y Cáncer, Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Sinesio Delgado 6, 28029 Madrid, Spain (e-mail: mpollan{at}isciii.es).
Background: Since the 1980s, Spain experienced two decades of sharply increasing breast cancer incidence. Declines in breast cancer incidence have recently been reported in many developed countries. We examined whether a similar downturn might have taken place in Spain in recent years.
Methods: Cases of invasive female breast cancer were drawn from all population-based Spanish cancer registries that had at least 10 years of uninterrupted registration over the period 1980–2004. Overall and age-specific changes in incidence rates were evaluated using change-point Poisson models, which allow for accurate detection and estimation of trend changes. All statistical tests were two-sided.
Results: A total of 80 453 incident cases of invasive breast cancer were identified. Overall age- and registry-adjusted incidence rates rose by 2.9% (95% confidence interval [CI] = 2.7% to 3.1%) annually during the 1980s and 1990s; there was a statistically significant change in this trend in 2001 (95% CI = 1998 to 2004; P value for the existence of a change point <.001), after which incidence declined annually by 3.0% (95% CI = 1.8% to 4.1%). This trend differed by age group: There was a steady increase in incidence for women younger than 45 years, an abrupt downturn in 2001 for women aged 45–64 years, and a gradual leveling off in 1995 for women aged 65 years or older. Separate analyses for registries that had at least 15 years of uninterrupted registration detected a statistically significant interruption of the previous upward trend in breast cancer incidence in provinces that had aggressive breast cancer screening programs and high screening participation rates, including Navarra (change point = 1991, P < .001), Granada (change point = 2002, P = .003), Bizkaia (change point = 1998, P < .001), Gipuzkoa (change point = 1998, P = .001), and Araba (change point = 1997, P = .002).
Conclusions: The recent downturn in breast cancer incidence among Spanish women older than 45 years is best explained by a period effect linked to screening saturation.
| CONTEXT AND CAVEATS Prior knowledge Breast cancer incidence in Spain has increased sharply since the 1980s. However, it is unclear whether Spain is experiencing the recent declines in breast cancer incidence that has been reported in many developed countries. Study design Data from all population-based Spanish cancer registries that had at least 10 years of uninterrupted registration over the period 1980–2004 were used to evaluate overall and age-specific changes in the incidence rates of invasive female breast cancer, taking into account the starting year of the corresponding breast cancer screening program for the population covered by the registry and the year in which the screening program achieved full coverage of the target population. Contribution Overall incidence rates increased during the 1980s and 1990s by 2.9% annually until 2001, after which incidence declined annually by 3.0%. There was a steady increase in incidence for women younger than 45 years, an abrupt downturn in 2001 for women aged 45–64 years, and a gradual leveling off in 1995 for women aged 65 years or older. Implications The recent downturn in breast cancer incidence among Spanish women older than 45 years is best explained by a period effect linked to screening saturation. Limitations The observed trends in breast cancer incidence might not be generalizable to all parts of Spain. Regional differences in the timing of breast cancer screening program implementation are likely to have increased the heterogeneity in incidence trends across registries. Data quality differed slightly across registries in terms of case completeness and diagnostic accuracy. From the Editors
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Manuscript received February 16, 2009; revised August 19, 2009; accepted September 14, 2009.
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J Natl Cancer Inst 2009 101: 1523.