Mammographic Screening of Women Attending a Reference Service Center in Southern Brazil

Background: To investigate the prevalence of and factors associated with performance of annual mammography by women above 40 years of age. Materials and Methods: This cross-sectional retrospective study was conducted at an oncology reference service in Southern Brazil from October 2013 to October 2014 with 525 women aged 40 years or older. Results: The prevalence of annual mammography was 54.1%; annual mammographic screening was performed for women without private medical insurance, who were under hormone replacement therapy and who had used contraception in the past. An association was found between non-performance of breast clinical and self-examination and non-performance of mammographic screening. Conclusions: Use of mammography for breast cancer screening in the public health care setting proved to be accessible; nevertheless, the proportion of screened women was low, and they exhibited poor adherence to the basic measures of care recommended for breast assessment. Thus, control of breast cancer requires implementing actions targeting the population most vulnerable to non-adherence to screening in addition to continuously monitoring and assessing that population to reduce the prevalence of this disease.     

A meta‐analysis of mammographic screening with and without clinical breast examination

Mammographic screening with clinical breast examination has been recommended in Japan since 2000. Although mammographic screening without clinical breast examination has not been recommended, its introduction is anticipated. The efficacies of mammographic screening with and without clinical breast examination were evaluated based on the results of randomized controlled trials. PubMed and other databases for studies published between 1985 and 2014 were searched. The study design was limited to randomized controlled trials to evaluate mortality reduction from breast cancer. Five studies were eligible for meta‐analysis of mammographic screening without clinical breast examination. The relative risk for women aged 40–74 years was 0.75 (95% confidence interval, 0.67–0.83). Three studies evaluated the efficacy of mammographic screening with clinical breast examination. The relative risk for women aged 40–64 years was 0.87 (95% confidence interval, 0.77–0.98). The number needed to invite was always lower in mammographic screening without clinical breast examination than in mammographic screening with clinical breast examination. In both screening methods, the number needed to invite was higher in women aged 40–49 years than in women aged 50–70 years. These results suggest that mammographic screening without clinical breast examination can afford higher benefits to women aged 50 years and over. Although evidence of the efficacy of mammographic screening without clinical breast examination was confirmed based on the results of the randomized controlled trials, a Japanese study is needed to resolve local problems.     

Current status of screening for breast cancer and tasks for introduction of mammographic screening in Japan

In the United States and Europe the high mortality of breast cancer has been significantly reduced by mammographic screening of women aged over 50 years, the effectiveness of which has been documented in many reports. In contrast, the effectiveness of such screening in women aged from 40 to 49 remains controversial. In Japan, breast cancer screening has consisted of physical examination alone, with inspection and palpation. Thus, more than half of the patients with breast cancer detected by this screening system are already aware of their lumps, the detection rate has been a little less than 0.1%, and the proportion of early-stage disease among breast cancers is only about 50%. It is difficult to detect breast cancer consisting of non-palpable tumors by physical examination, and the low sensitivity of this screening method has been pointed out. In Japan, there is no difference in overall survival between cases detected by screening and those detected in outpatient clinics. The results of the mammographic screening trial performed in Miyagi and Tokushima, which were promising in terms of proportions of early-stage cancer and no nodal involvement, strongly suggest its usefulness in Japan as well as in other countries. However, long-term results are not yet available. It is advocated that screening for breast cancer should be performed by means of mammography to improve the screening sensitivity, and increase the proportion of early-stage breast cancers. Mammo-graphic screening, either mammography and physical examination separately or simultanously in combination, has been effective for women aged over 50 years in Japan. However, with regard to those aged under 49 years, further studies are needed.     

Patterns of treatment for older women with newly diagnosed breast carcinoma

The patterns of treatment for newly diagnosed breast carcinomas in older women aged 65 years or more have not been well studied, particularly in relation to screening mammography performed for the early detection of breast cancer. Therefore, the present study was performed to determine the patterns of treatment for newly diagnosed breast carcinomas in older women aged 65 years or more and to determine the impact of screening mammography on these patterns of treatment. The study population consisted of 130 women aged 65 years or more with newly diagnosed breast carcinoma from 1993 through 1994 enrolled in a large health maintenance organization. The medical records of these 130 patients were reviewed. The breast cancers detected in women who had undergone mammographic screening were more often eligible for breast-conservation treatment than the breast cancers detected in women who had not undergone mammographic screening (79% vs. 48%, respectively; p = 0.0044). For the breast cancers that were eligible for breast-conservation treatment, breast-conservation treatment was used more often for the women who had undergone mammographic screening than for the women who had not undergone mammographic screening (70% vs. 27%, respectively; p = 0.0077). Definitive radiation therapy was delivered after breast-conservation surgery in 89% (55/62) of the patients. Medical oncology consultation was obtained more commonly for more advanced staged breast cancers. Clinical management was altered in 9% (12/130) of the patients because of older patient age, comorbid medical conditions, or both. These findings have documented the patterns of treatment for older women aged 65 years or more with newly diagnosed breast cancer. Screening mammography had a significant impact on the patterns of breast cancer management, as demonstrated by the association of screening mammography with an increased eligibility for breast-conservation treatment and an increased use of breast-conservation treatment for eligible patients.     

Followup after 11 years – update of mortality results in the Stockholm mammographic screening trial

Results from several randomised mammography screening trials haveshown that it is possible to reduce mortalityin breast cancer by mammographic screening at leastfor women above 50 years of age. Thepurpose of this article is to present dataon mortality in breast cancer in study andcontrol groups of the Stockholm trial after 11years of followup, to analyse which age groupbenefits most from screening. In March 1981, 40,318women in Stockholm, aged 40 through 64 years,entered a randomized trial of breast cancer screeningby single view mammography alone, versus no interventionin a control group of 20 000 women.Two screening rounds were performed and the attendancerate was over 80% in the two rounds.During 1986 the control group was invited onceto screening. Totally 428 and 217 cases ofbreast cancer were diagnosed in the study andcontrol groups respectively. After a mean follow-up of11.4 years a nonsignificant mortality reduction of 26%was observed for the whole study group, witha relative risk (RR) of death in breastcancer of 0.74 (CI(confidence interval)=0.5–1.1). Forwomen aged 50–64 years a significant 38% mortalityreduction was observed with a RR of 0.62(CI=0.38–1.0). For women aged 40–49 yearsno effect on mortality was found, with aRR of death in breast cancer of 1.08(CI=0.54–2.17). The breakpoint for benefit inthis study seemed to be at 50 yearsof age when 5-year age groups were analysed,but this tendency is uncertain because of thelow statistical power in the analysis of theyounger age groups. Long screening intervals, the useof single-view mammography, and the fact that morethan 50% of the women in age group40–49 years were still below 50 years ofage when the study was closed, were allfacts that could have influenced the results inage group 40–49 years. Larger studies are neededto answer the question whether mammographic screening canbe successful in younger age groups.     

Abnormal mammographic findings with short-interval follow-up recommendation

An abnormal Breast Imaging and Reporting Data System (BIRADS) category 3 mammogram with a short interval follow-up recommendation is a common finding seen in approximately 40% of women for each decade of screening. Factors associated with category 3 mammograms include mammography examination features, tendencies of the interpreting physician, and features of the country's health care system and the screened population including age, family history, previous biopsies, obesity, and menopausal hormone therapy. Recently, the degree to which a BIRADS category 3 mammographic result provides differential breast cancer risk compared with normal mammographic categories (BIRADS category 1 or 2) has been questioned. The yield of category 3 mammographic results could potentially be increased by more uniform performance of additional imaging workup (additional views and/or ultrasonography). In addition, other strategies to more accurately characterize the risk of breast cancer in women with category 3 mammographic results are under evaluation and including magnetic resonance imaging, computer-aided classification systems, and digital tomosynthesis. Given the potential psychologic impact of abnormal mammographic results, studies attempting to more accurately relate screening mammography findings to breast cancer risk are a priority.     

Impact of screening mammography on mortality from breast cancer before age 60 in women 40 to 49 years of age

Background

Whether screening mammography programs should include women in their 40s is controversial. In Canada, screening of women aged 40–49 years has not been shown to reduce mortality from breast cancer. Given that screening mammography reduces mean tumour size and that tumour size is inversely associated with survival, the lack of benefit seen with screening is puzzling and suggests a possible adverse effect on mortality of mammography or subsequent treatment (or both) that counterbalances the expected benefit derived from downstaging.

Methods

We followed 50,436 women 40–49 years of age until age 60 for mortality from breast cancer. Of those women, one half had been randomly assigned to annual mammography and one half to no mammography. The impact of mammography on breast cancer mortality was estimated using a left-censored Cox proportional hazards model.

Results

Of 256 deaths from breast cancer recorded in the study cohort, 134 occurred in women allocated to mammography, and 122 occurred in those receiving usual care and not allocated to mammography. The cumulative risk of death from breast cancer to age 60 was 0.53% for women assigned to mammography and 0.48% for women not so assigned. The hazard ratio for breast cancer–specific death associated with 1 or more screening mammograms before age 50 was 1.10 (95% confidence interval: 0.86 to 1.40).

Conclusions

Mammography in women 40–49 years of age is associated with a small but nonsignificant increase in the risk of dying of breast cancer before age 60. Caution should be exercised when recommending mammographic screening to women before age 50.     

Radiation risk and mammographic screening of women from 40 to 49 years of age: effect on breast cancer rates and years of life

The aim of this study was to evaluate the carcinogenic risks associated with radiation in mass mammographic screening. Assessment was in terms of breast cancer mortality and years of life for a hypothetical cohort of 100 000 women. Data were obtained on incidence, mortality and life expectancy for the female population of Stockholm. With a screening interval of 18 months at ages 40-49 years, a total absorbed dose to the breast of 13 mGy per invited woman; and an annual breast cancer reduction of 25% per year 7 years from screening start, the net number of years gained was at least 2800. However, using the highest absorbed dose reported in routine mammographic screening in Sweden (approximately 3 mGy per view), and the highest reported radiation risk in the literature, a programme entailing annual screening with 2 views would require at least a 20% annual reduction in breast cancer mortality to give a net benefit in both the number of years of life gained and number of breast cancer deaths avoided. This observation supports the conclusion that exposures with low absorbed dose are essential when performing mass screening with mammography among young women.     

Features of Microcalcifications on Screening Mammography in Young Women

Background: There is no decrease in the number of breast cancer deaths if screening mammography is performedin women aged hereditary breast cancer. Therefore, more accurate screening mammography for young women is needed. Objective: Toevaluate the features of screening mammographic findings, particularly microcalcifications, in women aged to increase the positive predictive value of screening mammography in young women. Methods: We retrospectivelyreviewed the data of consecutive women who underwent opportunistic and organized breast cancer screening at theSakuragaoka Hospital (Shizuoka, Japan) between April 2013 and March 2015. We compared the mammographicfindings and features of microcalcifications between women aged Results: The study included 3645 women. Of these 3645 women, 415 (11.4%) were aged were aged 40–49 years, and 2011 (55.2%) were aged 50–74 years. Women aged recalled for microcalcifications than those aged 50–74 years (Young women were more likely to be recalled for small round and segmental microcalcifications [(OR): 1.799 (95% CI: 0.751–2.846); 40–49 years, OR: 1.394 (95% CI: 0.714–2.074)] and less likely to be recalled forsmall round and grouped microcalcifications [(95% CI: 0.496–1.428)] compared with women aged 50–74 years. Conclusions: On screening mammography, womenaged microcalcifications. False-positive results may be reduced by reflecting the characteristics of microcalcification findingsamong young women without breast cancer in the future.     

Mammography in symptomatic and asymptomatic patients

It is now generally accepted that screening mammography at 1- to 3-year intervals can decrease mortality from breast cancer. Three randomized trials, involving a total of 238,000 women, have reported mortality results. In two trials (HIP and S2C), there was a significant reduction in breast cancer mortality (22 per cent at 18 years and 27 per cent at 8 years). One trial (M?lmo) showed a nonsignificant reduction in mortality at year 9 (5 per cent) and nonsignificant increases in mortality at earlier years. There are little data from randomized trials to support a benefit of mammographic screening in women under 50 years old. The two Swedish studies at last follow-up had 26 and 29 per cent more breast cancer deaths in young women in the group randomized to screening. The HIP study had 25 per cent fewer breast cancer deaths at 18 years in women under age 50 at the start of the trial, but because only 12 patients under age 50 had mammographically detectable tumors (out of 89 cancers diagnosed in the screened group), most of the benefit must be due to physical examinations or increased awareness of breast cancer symptoms. The as yet unpublished results of the Canadian trial in women under age 50 should elucidate the benefit of mammography in this age group. American centers report a malignant biopsy rate of 20 to 30 per cent for clinically occult lesions. This rate should increase as the proportion of women who have had prior mammography increases. High-quality mammography, including magnification technique for evaluation of suspicious lesions, proper localization and excisional biopsy techniques with pathologic correlation, and potentially, fine-needle aspiration, may improve the yield of screening mammography-induced open-biopsy procedures. Magnification technique can improve mammographic assessment of the extent of the tumor and guide re-excision for patients being considered for breast-conserving therapy. In the irradiated breast, in our experience, mammography alone detected 35 per cent of recurrent cancers in the irradiated breast. We recommend routine mammographic follow-up of the irradiated breast, including magnification of the local excision site, at 6 months, 1 year, and annually thereafter.     

Mammographic appearances of mammary duct ectasia that mimic carcinoma in a screening programme

The aim of this study is to demonstrate the spectrum of mammographic appearances of mammary duct ectasia that mimic carcinoma in a breast cancer screening programme. Between February 1989 and March 1993, 40 003 women underwent screening mammography as part of the Western Australia Women's Cancer Prevention Unit screening programme. Fine needle aspiration or excisional biopsy was performed on 1437 women, and 12 cases of cytologically or histologically confirmed mammary duct ectasia were detected. A total of 14 mammographic abnormalities from 12 asymptomatic female patients were biopsied, and confirmed to represent mammary duct ectasia. The mammographic spectrum included eight areas of microcalcification (two of which were extensive), three spiculated masses and three lobulated, partially smooth masses. Five of these women showed no other mammographic stigmata of mammary duct ectasia in either breast. Additional features of mammary duct ectasia, including nipple retraction, retro-areolar duct dilatation or macrocalcification were identified in seven women. Mammographic features of mammary duct ectasia are frequently detected in asymptomatic women undergoing screening mammography and cause no diagnostic dilemma. Occasionally mammary duct ectasia will have a mammographic appearance that is indistinguishable from carcinoma, necessitating breast biospy. In this study 40% of those women with mammary duct ectasia that were submitted for biopsy had no other feature of mammary duct ectasia that could have suggested the pre-operative diagnosis.     

Mammographic screening for young women with a family history of breast cancer: knowledge and views of those at risk

Although the effectiveness of mammography for women under the age of 50 years with a family history of breast cancer (FHBC) has not yet been proven, annual screening is being offered to these women to manage breast cancer risk. This study investigates women's awareness and interpretation of their familial risk and knowledge and views about mammographic screening. A total of 2231 women from 21 familial/breast/genetics centres who were assessed as moderate risk (17-30% lifetime risk) or high risk (>30% lifetime risk) completed a questionnaire before their mammographic screening appointment. Most women (70%) believed they were likely, very likely or definitely going to develop breast cancer in their lifetime. Almost all women (97%) understood that the purpose of mammographic screening was to allow the early detection of breast cancer. However, 20% believed that a normal mammogram result meant there was definitely no breast cancer present, and only 4% understood that screening has not been proven to save lives in women under the age of 50 years. Women held positive views on mammography but did not appear to be well informed about the potential disadvantages. These findings suggest that further attention should be paid to improving information provision to women with an FHBC being offered routine screening.     

Screening for breast cancer

Screening for breast cancer using the combination of physical examination of the breasts and mammography was effective in women age 50 or more in the HIP study. However, major questions remain, especially the benefit of screening women age 40-49, and the independent effect of mammography. Such questions can only be answered by large-scale randomized controlled trials, and trials to answer these questions are now underway in Canada (the NBSS) and Sweden. Only the NBSS, however, is attempting to replicate the HIP study in women age 40-49, and to evaluate the additional contribution of mammography to annual physical examination in women age 50-59. The Swedish studies are evaluating the effectiveness of mammography alone, while studies in Britain will help to evaluate breast self-examination (BSE) and biannual mammography with annual physical examination. Because much of the benefit in HIP could have derived from the physical examination, it is necessary to complete the present trials before population-based screening for breast cancer using mammography can be advocated. Trials are justifiable because the risk of mammographic screening seems likely to be negligible, and the use of the combination of annual mammography and physical examination to be cost-effective. In the meantime, there seems no immediate substitute on a population basis for efficient physical examination of the breasts by primary care physicians coupled with breast self-examination by the woman. Techniques such as ultrasound and diaphanography seem unlikely to supplant mammography in screening, and in any case, have to be evaluated in comparison with mammography.     

Beyond randomized controlled trials: organized mammographic screening substantially reduces breast carcinoma mortality

BACKGROUND: The efficacy of mammographic screening in the reduction of breast carcinoma mortality has been demonstrated in randomized controlled trials. However, the evaluation of organized screening outside of research settings (so-called "service screening") faces unique methodologic and conceptual challenges. The current study describes the evaluation of organized mammography screening in a clinical setting and demonstrates the benefit obtained from service screening in two Swedish counties. METHODS: In the group of subjects ages 20--69 years, there were 6807 women diagnosed with breast carcinoma over a 29-year period in 2 counties in Sweden and 1863 breast carcinoma deaths. All patients were classified from patient charts based on their screening status (i.e., whether they had been invited to undergo screening and whether they actually had undergone screening). The number of women who lived in the 2 counties during the 29-year study period was provided by the Central Bureau of Statistics. Breast carcinoma-specific mortality was compared across three time periods: 1) 1968--1977, when no screening was taking place because mammography had not been introduced; 2) 1978--1987, the approximate period of the Two-County randomized controlled trial of screening in women ages 40--74 years; and 3) 1988--1996, when all women in the 2 counties ages 40--69 years were invited to undergo screening (service screening). When comparing breast carcinoma mortality in screened women with that in women diagnosed before screening was introduced, a correction for self-selection bias was incorporated to prevent overestimation of the benefit of screening. RESULTS: The mortality from incident breast carcinoma diagnosed in women ages 40-69 years who actually were screened during the service screening period (1988--1996) declined significantly by 63% (relative risk [RR] = 0.37; 95% CI, 0.30--0.46) compared with breast carcinoma mortality during the time period when no screening was available (1968--1977). The mortality decline was 50% (RR = 0.50; 95% CI, 0.41--0.60) when breast carcinoma mortality among all women who were invited to undergo screening (nonattendees included) was compared with breast cancer mortality during the time period when no screening was available (1968--1977). The reduction in mortality observed during the service screening period, adjusted for selection bias, was 48% (RR = 0.52; 95% CI, 0.43--0.63). No significant change in breast carcinoma mortality was observed over the three time periods in women who did not undergo screening. This group included women ages 20--39 years because these individuals were never invited to undergo screening, and women ages 40--69 years who did not undergo screening (not invited during the randomized trial or invited during the second and third time periods but declined). CONCLUSIONS: Regular mammographic screening resulted in a 63% reduction in breast carcinoma death among women who actually underwent screening. The policy of invitation to organized screening with mammography appears to have reduced breast carcinoma mortality by 50% in these 2 counties.     

Modelling the overdiagnosis of breast cancer due to mammography screening in women aged 40 to 49 in the United Kingdom

Introduction

Overdiagnosis of breast cancer due to mammography screening, defined as the diagnosis of screen-detected cancers that would not have presented clinically in a women''s lifetime in the absence of screening, has emerged as a highly contentious issue, as harm caused may question the benefit of mammographic screening. Most studies included women over 50 years old and little information is available for younger women.

Methods

We estimated the overdiagnosis of breast cancer due to screening in women aged 40 to 49 years using data from a randomised trial of annual mammographic screening starting at age 40 conducted in the UK. A six-state Markov model was constructed to estimate the sensitivity of mammography for invasive and in situ breast cancer and the screen-detectable mean sojourn time for non-progressive in situ, progressive in situ, and invasive breast cancer. Then, a 10-state simulation model of cancer progression, screening, and death, was developed to estimate overdiagnosis attributable to screening.

Results

The sensitivity of mammography for invasive and in situ breast cancers was 90% (95% CI, 72 to 99) and 82% (43 to 99), respectively. The screen-detectable mean sojourn time of preclinical non-progressive and progressive in situ cancers was 1.3 (0.4 to 3.4) and 0.11 (0.05 to 0.19) years, respectively, and 0.8 years (0.6 to 1.2) for preclinical invasive breast cancer. The proportion of screen-detected in situ cancers that were non-progressive was 55% (25 to 77) for the first and 40% (22 to 60) for subsequent screens. In our main analysis, overdiagnosis was estimated as 0.7% of screen-detected cancers. A sensitivity analysis, covering a wide range of alternative scenarios, yielded a range of 0.5% to 2.9%.

Conclusion

Although a high proportion of screen-detected in situ cancers were non-progressive, a majority of these would have presented clinically in the absence of screening. The extent of overdiagnosis due to screening in women aged 40 to 49 was small. Results also suggest annual screening is most suitable for women aged 40 to 49 in the United Kingdom due to short cancer sojourn times.     

Mammographic screening for non-palpable breast cancer in Japan

In Japan, mammography was endorsed for breast cancer screening in women aged 40 and over by the Ministry of Health, Labor and Welfare in 2004. The spread of mammographic screening has caused an increase in the incidence of non-palpable breast cancer. Precision reading for mammography is necessary to detect non-palpable breast cancer. When mass and focal asymmetric density is noted, it is important to analyze the density, density gradient, internal structure, margin and associated findings. Calcifications are classified by morphology and distribution mainly. It is necessary to distinguish secretor-type calcifications from necrotic-type calcifications. The Iwate Cancer Association performed a population-based screening program for breast cancer using mammography combined with clinical breast examination of 42,065 women in Iwate Prefecture from 1999 to 2003. A total of 2,329(5.7%)women were recalled and the 112 cases(0.27%) of cancer were detected in 114 breasts. Of 114 breast cancers, 40 (35%) were non-palpable and 74(65%) were palpable. The early breast cancer (stage 0 and I) rate of the non-palpable group was significantly higher than that of the palpable group (90% and 47%, p = 0.0003). The node-negative rate of the non-palpable group was significantly higher than that of the palpable group (92% and 68%, p = 0.011). It is expected that mammographic screening will be expanded and that the mortality rate from breast cancer in Japan will decrease, as in Europe and the United States.     

Breast cancer in New South Wales in 1972-1995: tumor size and the impact of mammographic screening.

To examine the use of mammographic screening in women in New South Wales (NSW), we measured uptake of initial mammograms and estimated the proportions of breast cancers that were screen detected. To see if mammographic screening has been associated with reductions in advanced breast cancers and mortality from breast cancer, we analyzed trends in age-specific and age-standardized breast cancer incidence and mortality from 1972 to 1995 and tumor size in 1986, 1989, 1992 and April to September 1995. Between 1984 and the end of 1995, an estimated 72% of NSW women in their 50s and 67% in their 60s had had at least 1 mammogram and, in 1995, an estimated 39% of invasive breast cancers in women in these age groups were detected by mammography. Before 1989, breast cancer incidence increased only slightly (+1.3% annually) but then, from 1990 to 1995, increased more rapidly (+3.1% annually). Between 1986 and 1995, rates of small cancers (< 1 cm) increased steeply by 2.7 times in women 40-49 years of age and 5.6 times in women 50-69 years of age. The incidence of large breast cancers (3+ cm), after little apparent change to 1992, fell by 17% in women 40-49 years of age and 20% in those 50-69 years of age to 1995. Breast cancer mortality increased slightly between 1972 and 1989 (+0.5% annually) but then fell (-2.3% annually) from 1990 to 1995. We concluded that breast cancer rates had been influenced in expected directions by the introduction of mammographic screening in women resident in NSW. We expect that recent falls in incidence of larger breast cancers and breast cancer mortality will become steeper as screening coverage increases in the second half of the 1990s.     

Imperfect Correlation of Mammographic and Clinical Breast Tissue Density

Background: Clinicians determine degree of mammographic density based on tissue firmness on breastexamination. The study aimed to compare breast density in mammography and clinical breast examination.Materials and Methods: Six-hundred sixty three women 40 years of age or older were studied. The breast examdensity was graded from 1 to 4 by two expert surgeons and the mammographic parenchymal density by twoexpert radiologists. Then for practical reasons, grades 1 and 2 were considered as low-density and grades 3 and 4as high-density. Results: High and low densities were detected in 84.5% and 15.5% of clinical breast examinationsand 59.7% and 40.3% of mammographies, respectively. The statistical analysis showed a significant differencebetween the breast tissue densities in breast examination with those in mammography. Conclusions: A clinicallydense breast does not necessarily imply a dense mammographic picture.     

Letter in response: breast cancer screening of women aged 70–74 years

The purpose of this study is to critically appraise the claim by Nickson et al. [1] that they have evidence supporting the Australian Government’s recent decision to extend the national free invitation for biennial mammography program (BreastScreen) to women aged 70–74 years. Since their claim was made on the basis of a significant difference in the incidence of larger primary breast cancers between women in this age group who are already participating in BreastScreen versus those who are not, an analysis of the stage at diagnosis of breast cancer in the USA versus mammographic screening over 30 years, evidence from breast cancer adjuvant endocrine and chemotherapy (adjuvant therapy) trials and data from an evaluation of BreastScreen and adjuvant therapy use in Australia were examined. By 1999, most Australian women aged 40–79 years were receiving adjuvant therapy that could cure breast cancer no matter what the size of the primary cancer. Further, the incidence primary breast cancers of all sizes had doubled in the USA during 30 years of mammographic screening, but the incidence of more advanced breast cancers had almost remained constant, indicating that adjuvant therapy, not mammographic screening, was the main cause of the 28 % reduction in breast cancer mortality that had been observed. In conclusion, the claim by Nickson et al. is not supported by available evidence. Further, BreastScreen should not have been extended to these older women before the UK trial, which is testing the efficacy of mammographic screening of women aged 70–74 years [8], had reported its results.