Recent changes in breast cancer incidence in Spain, 1980-2004.
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.
Area de Epidemiología Ambiental y Cáncer, Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Madrid, Spain. mpollan@isciii.es
Marina
M
Pollán
Roberto
R
Pastor-Barriuso
Eva
E
Ardanaz
Marcial
M
Argüelles
Carmen
C
Martos
Jaume
J
Galcerán
María-José
MJ
Sánchez-Pérez
María-Dolores
MD
Chirlaque
Nerea
N
Larrañaga
Ruth
R
Martínez-Cobo
María-Cres
MC
Tobalina
Enrique
E
Vidal
Rafael
R
Marcos-Gragera
Antonio
A
Mateos
Isabel
I
Garau
María-Dolores
MD
Rojas-Martín
Rosario
R
Jiménez
Ana
A
Torrella-Ramos
Josefina
J
Perucha
Maria-Eugenia
ME
Pérez-de-Rada
Susana
S
González
María-José
MJ
Rabanaque
Joan
J
Borràs
Carmen
C
Navarro
Esther
E
Hernández
Angel
A
Izquierdo
Gonzalo
G
López-Abente
Carmen
C
Martínez
D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D008403:Mass Screening / Q000706:statistics & numerical data; D008875:Middle Aged; D012042:Registries; D013030:Spain / Q000453:epidemiology; D013997:Time Factors