Mammographic screening before age 50 years in the UK: comparison of the radiation risks with the mortality benefits

Abstract

Mammographic screening before age 50 years is less effective than at older ages and the associated radiation risks are higher. We estimated how many breast cancer deaths could be caused and how many could be prevented by a decade of annual two-view mammographic screening starting at ages 20, 30 and 40 years, respectively, in the UK; for all women, and for women with first-degree relatives affected with breast cancer. We extrapolated from a radiation risk model to estimate the number of radiation-induced breast cancer deaths, and used results from randomised trials, which suggest a reduction in breast cancer mortality of 10 -20% in women invited to screening before age 50 years, to estimate the number of deaths that could be prevented. The net change in breast cancer deaths was defined as the number of radiation-induced deaths minus the number of prevented deaths. For all women, assuming a reduction in mortality from screening of 20%, a decade of annual screening was estimated to induce more deaths than it prevents if started at age 20 years and at age 30 years (net increase ¼ 0.86 and 0.37 breast cancer deaths, respectively, per 1000 women screened). The corresponding estimate for screening starting at age 40 years was a net decrease of 0.46 deaths/1000 women screened and a zero net change assuming a 10% mortality reduction. Results for women with first-degree relatives with breast cancer were generally in the same direction but, because their background incidence rates are higher, the net increases or decreases were greater. In conclusion, our estimates suggest that a decade of annual two-view mammographic screening before age 40 years would result in a net increase in breast cancer deaths, and that starting at age 40 years could result in a material net decrease only if breast cancer mortality is reduced by about 20% or more in women screened. Although these calculations were based on a number of uncertain parameters, in general, the conclusions were not altered when these parameters were varied within a feasible range. The National Health Service Breast Screening Programme currently invites women in the UK aged 50 -70 years for mammographic screening once every 3 years. Whether screening should be offered to women younger than age 50 years, particularly to those thought to be at a higher than average risk of the disease because of a family history of breast cancer, is a question that is frequently raised. However, mammographic screening before age 50 years is less effective than at older ages possibly because premenopausal women have denser breasts and because the tumours grow more rapidly (Buist et al, 2004). Preliminary results from the UK Age Trial suggest that the reduction in breast cancer mortality associated with offering annual mammographic screening from age 40 to 47/48 years may be 10% (Moss et al, 2005), which is considerably lower than the 25% reduction achieved in randomised trials offering regular screening to women aged 50 -69 years (IARC, 2002).Exposure to mammographic X-rays confers a risk of...

Breast and ovarian cancer screening of non-carriers from BRCA1/2 mutation-positive families: 2-year follow-up of cohorts from France and Quebec

“…The lifetime risk of radiation-induced breast cancer may be higher in women who start having mammograms at a relatively young age because of extended total exposure. 29,30 As our ability to estimate individual breast cancer risk improves through understanding additional genetic and environmental factors involved in familial clustering, it may eventually be feasible to target female non-carriers from BRCA mutation-positive families who may benefit from more intensive screening. 31 Our findings have implications for the follow-up of women from families that carry BRCA1/2 mutations, but for whom genetic test results are negative.…”

Radiation risk of breast screening in England with digital mammography

“…Some authors suggest a DDREF of 1.0. 2,7,21,22 They argue that a reduction factor does not apply in cases where fractionated high-dose rate radiation is received. Some suggest a DDREF of 1.5 15 based on estimates of curvature of the dose-response curve from experimental animal data and from the latest Life Span Study data on solid cancer incidence.…”

“…[2][3][4][5] These studies consider different screening regimes and age ranges than those in the NHSBSP. Studies relating to the breast screening programme in the UK include the NHSBSP Report 54, 6 Berrington de González and Reeves 7 and the Report of the Independent Advisory Group on Ionizing Radiation. 8 Berrington de González and Reeves 7 compared the radiation risk with the mortality benefits of screening females under the age of 50 years, outside the current screening age range in the NHSBSP.…”

Education for Radiological Technologists and Their Place in Mammography Diagnostic Methods

“…Most patients are female (97.3%), which aligns with comparative studies that analyze the disease by sex. MRI is more a significant diagnostic method, , but there is a higher cost for this type of examination (Berrington de Gonzalez & Reeves, 2005;Kriege et al, 2004;MARIBS Study Group, 2006). Mammography, like MRI, has a dose of radiation, and for this reason has special protocols for screening (Law & Faulkner, 2001;Law, Faulkner, & Young, 2007;Mattsson & Rutquvist, 2000).…”