The Gothenburg breast screening trial

BACKGROUND. The effect of mammography screening on breast carcinoma mortality in women ages < 50 years remains unclear. METHODS. A randomized trial of invitation to breast carcinoma screening with mammography was performed in the city of Gothenburg, Sweden. The purpose was to estimate the effect of mammographic screening on breast carcinoma mortality in women ages < 50 years. Randomization was initially by day-of-birth cluster (18% of subjects), and subsequently by individual (82% of subjects). Between September 1983 and April 1984, 11,724 women ages 39-49 years were randomized to the study group. This group was invited to mammographic screening every 18 months. Two-view mammography was used at each screen unless the density of the breast at the previous screen indicated that single view was adequate. Fourteen thousand two hundred and seventeen women in the same age range were randomized to a control group that was not invited to undergo screening until the fifth screen of the study group (between 6 and 7 years after randomization). Women with breast carcinoma diagnosed up to the time immediately after the first screen of the control group were followed for death from breast carcinoma until the end of December 1994. RESULTS. A 45% reduction in mortality from breast carcinoma was observed in the study group compared with the control group (relative risk [RR] = 0.55, P = 0.035, 95% confidence interval [CI], 0.31-0.96). A conservative estimate based on removal of the tumors detected at the first screen of the control group gave a mortality reduction of 44% (RR = 0.56, P = 0.046, 95% CI, 0.31-0.99). In both cases, the effect was statistically significant. CONCLUSIONS. Mammographic screening can reduce mortality from breast carcinoma in women ages < 50 years. The mortality reduction can be substantial if high quality mammography is used and an 18-month interscreening interval is strictly adhered to.

[1]  S. Duffy,et al.  Modelling the analysis of breast cancer screening programmes: sensitivity, lead time and predictive value in the Florence District Programme (1975-1986). , 1991, International journal of epidemiology.

[2]  A. Miller,et al.  Canadian National Breast Screening Study: 2. Breast cancer detection and death rates among women aged 50 to 59 years. , 1992, CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne.

[3]  S. Duffy,et al.  The Gothenburg breast screening trial , 1998, Cancer.

[4]  J. Frisell,et al.  The Stockholm Mammographic Screening Trial: Risks and benefits in age group 40-49 years. , 1997, Journal of the National Cancer Institute. Monographs.

[5]  R. Tarone.  The excess of patients with advanced breast cancer in young women screened with mammography in the Canadian National Breast Screening Study , 1995, Cancer.

[6]  N Segnan,et al.  Adjusting for non-compliance and contamination in randomized clinical trials. , 1997, Statistics in medicine.

[7]  T. Landberg,et al.  Mammographic screening and mortality from breast cancer: the Malmö mammographic screening trial. , 1988, BMJ.

[8]  A. Miller,et al.  Periodic Screening for Breast Cancer: The Health Insurance Plan Project and its Sequelae, 1963–1986 , 1989 .

[9]  L. Tabár,et al.  What is the optimum interval between mammographic screening examinations? An analysis based on the latest results of the Swedish two-county breast cancer screening trial. , 1987, British Journal of Cancer.

[10]  D. Spiegelhalter,et al.  Modelling Complexity: Applications of Gibbs Sampling in Medicine , 1993 .

[11]  C. Smart,et al.  The canadian national breast screening study. An appraisal and implications for early detection policy , 1993, Cancer.

[12]  S. Feig,et al.  Increased benefit from shorter screening mammography intervals for women ages 40‐49 years , 1997, Cancer.

[13]  P. Glasziou,et al.  Mammographie screening trials for women aged under 50: A quality assessment and meta‐analysis , 1995 .

[14]  L. Tabár,et al.  Efficacy of breast cancer screening by age. New results swedish two‐county trial , 1995, Cancer.

[15]  A. Miller,et al.  Canadian National Breast Screening Study: 1. Breast cancer detection and death rates among women aged 40 to 49 years. , 1992, CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne.

[16]  S. Feig,et al.  The Canadian National Breast Screening Study: a critical review. , 1993, AJR. American journal of roentgenology.

[17]  C J Baines,et al.  The Canadian National Breast Screening Study: update on breast cancer mortality. , 1997, Journal of the National Cancer Institute. Monographs.

[18]  B. Macmahon,et al.  Randomization in the Canadian National Breast Screening Study: a review for evidence of subversion. , 1997, CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne.

[19]  Sweden.,et al.  Breast-cancer screening with mammography in women aged 40–49 years , 1996 .

[20]  R. Hendrick,et al.  Benefit of screening mammography in women aged 40-49: a new meta-analysis of randomized controlled trials. , 1997, Journal of the National Cancer Institute. Monographs.

[21]  N. Breslow,et al.  Statistical methods in cancer research: volume 1- The analysis of case-control studies , 1980 .

[22]  E. Thurfjell,et al.  Population-based mammography screening in Swedish clinical practice: prevalence and incidence screening in Uppsala County. , 1994, Radiology.

[23]  L. Tabár,et al.  Sojourn time, sensitivity and positive predictive value of mammography screening for breast cancer in women aged 40-49. , 1996, International journal of epidemiology.

[24]  B. Muir,et al.  The Edinburgh randomised trial of breast cancer screening: results after 10 years of follow-up. , 1994, British Journal of Cancer.

[25]  L. Tabár,et al.  Update of the Swedish two-county program of mammographic screening for breast cancer. , 1992, Radiologic clinics of North America.

[26]  S. Duffy,et al.  The Gothenburg Breast Cancer Screening Trial: preliminary results on breast cancer mortality for women aged 39-49. , 1997, Journal of the National Cancer Institute. Monographs.

[27]  S. Wall,et al.  Breast cancer screening with mammography: overview of Swedish randomised trials , 1993, The Lancet.

[28]  I Andersson,et al.  Reduced breast cancer mortality in women under age 50: updated results from the Malmö Mammographic Screening Program. , 1997, Journal of the National Cancer Institute. Monographs.

[29]  G. Fagerberg,et al.  Determination of cause of death among breast cancer cases in the Swedish randomized mammography screening trials. A comparison between official statistics and validation by an endpoint committee. , 1995, Acta oncologica.