Effects of Age,Breast Density and Volume on Breast Cancer Diagnosis: A Retrospective Comparison of Sensitivity of Mammography and Ultrasonography in China’s Rural Areas

Purpose: Mammography has been confirmed as the only effective mode to improve the prognosis of patientswith breast cancer in Western developed countries, but might not be a good choice in other areas of the world.One of the major challenges in China is to determine an optimal imaging modality for breast cancer screening.This study was designed to clarify the sensitivity of ultrasonography compared with that of mammography inrural China. Methods: We retrospectively studied the sensitivity of mammography and ultrasonography basedon 306 breast cancer patients detected by the program of “screening for cervical cancer and breast cancer”performed in Chinese rural areas between January 2009 and December 2011, and analyzed the effects of age,breast density and volume on the sensitivity. Results: Stratified analysis showed that the sensitivity of breastultrasonography was significantly higher than that of mammography in premenopausal patients (81.4% vs.61.1%, p=0.02), in women ≤ 55 years of age (82.2% vs. 63.4%, p<0.01), in the high breast density group (AmericanCollege of Radiology [ACR] levels 3-4) (85.9% vs. 60.6%, p<0.01) and in the small breast volume group (≤400ml) (87.1% vs. 66.7%, p<0.01). Age had a significant effect on sensitivity of mammography (breast density andvolume-adjusted odds ratio, 6.39; 95% confidence interval, 2.8-14.4 in age group > 55 compared to age group≤ 45), but not that of ultrasonography. Neither breast density nor volume had significant effect on sensitivityof mammography or ultrasonography. Conclusions: Ultrasonography is more sensitive than mammography indetecting breast cancer in women under 55 year-old Chinese, especially in those with high-density and relativelysmall breasts.     

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.     

Mammographic screening after the age of 65 years: early outcomes in the Nijmegen programme.

We studied outcomes of mammographic screening in women older than 65 years. In 1975, breast cancer screening was started in Nijmegen, The Netherlands, for women aged 35-65 years. Since 1977, approximately 7700 older women have also been invited for biennial one-view mammography. This report is based on ten screening rounds from 1975 to 1994. The results of the subsequent screening rounds in the age groups 65-69 years, 70-74 years and 75 years and older were: participation rates 55%, 39% and 15%; screen-detected cancer rates 5.6%, 6.9% and 7.8%; interval cancer rates 2.0%, 1.8%, and 3.5%; and predictive values of referral 62%, 64% and 62% respectively. In all age groups, screen-detected patients had smaller tumours and a lower prevalence of axillary lymph node involvement than unscreened patients. Our conclusion is that, in women aged 65 years, and older, breast cancer can be detected at an earlier stage by mammographic screening.     

Cost-effective mammography screening in Korea: High incidence of breast cancer in young women

The epidemiological characteristics of breast cancer in Korean women are different from the characteristics reported in Western women. The highest incidence rate occurs in Korean women in their 40s. The purpose of this study was to determine the most cost-effective screening interval and target age range for Korean women from the perspective of the national healthcare system. A stochastic model was used to simulate breast cancer screenings by varying both the screening intervals and the age ranges. The effectiveness of mammography screening was defined as the probability of detecting breast cancer in the preclinical state and the cost was based on the direct cost of mammography screening and the confirmative tests. The age-specific mean sojourn times and the sensitivity of the mammography were applied in the stochastic model. An optimal cost-effectiveness was determined by the incremental cost-effectiveness ratio and lifetime schedule sensitivity. Sensitivity analyses were undertaken to assess parameter uncertainty. The selected cost-effective strategies were: (1) the current biennial mammography screenings for women who are at least 40 years old; (2) biennial screening for women between the ages of 35 and 75 years; and (3) a combination strategy consisting of biennial screening for women aged between 45 and 54 years, and 3-year interval screening for women aged between 40 and 44 years and 55 and 65 years. Further studies should follow to investigate the effectiveness of mammography screening in women younger than 40 years in Asia as well as in Korea. ( Cancer Sci 2009; 100: 1105–1111)     

Relationship between mammographic density and the risk of breast cancer in japanese women: a case-control study

BACKGROUND: The relationship between mammographic density and the risk of breast cancer was examined in Japanese women. The study was a matched case-control study comparing the mammographic densities of both breast cancer cases and healthy controls. MATERIALS AND METHODS: We selected 237 women who were diagnosed with a histologically verified breast cancer, and who underwent surgery at Gihoku General Hospital in Gifu, from January, 1998 to December, 1999. During the time of this study, 3,650 people participated in breast cancer screening with mammography and ultrasound together. We selected 742 women as a control group from the screening participants and matched them by age and the number of deliveries with the cancer patients. The same mammography machine was used for both cases and controls. For evaluation, we used a visual method (Wolfe's classification) and a computer assisted method to classify the mammograms based on mammographic density. RESULTS: (1) According to Wolfe's classification, the DY group had a significantly increased breast cancer risk compared with the N1 group (Relative risk (RR)=2.20, 95% confidence interval (95%CI) (1.02-4.77). (2) The group showing a high mammographic density had a significantly increased risk of breast cancer compared with the group with low mammographic density (RR=2.83, 95%CI=1.33-5.98) as classified by the computer assisted method. CONCLUSION: It is suggested that women with high mammographic densities, classified visually or by computer, have an elevated risk of breast cancer compared with those with low mammographic densities.     

Mammography Screening and Breast Cancer Mortality in New South Wales, Australia

OBJECTIVE: To investigate the relationship between utilisation of service mammography screening and breast cancer mortality in New South Wales (NSW) women. Setting : Population-based biennial mammography screening was progressively introduced in NSW from 1988, with active recruitment and re-invitation for women aged 50-69 years, and reached full geographic coverage by 1996. Biennial mammography screening participation has varied widely over time and by municipality. METHODS: Breast cancer mortality by age, period and municipality was obtained from the NSW Central Cancer Registry. Biennial mammography screening rates for the same strata were obtained from the BreastScreen NSW database. Temporal changes in breast cancer mortality for NSW were summarised as annual average declines using Poisson regression. Breast cancer mortality for 1997-2001 was examined in relation to lagged biennial screening rates by municipality, adjusted for age, area socio-economic and geographic indicators, and breast cancer incidence, also using Poisson regression. RESULTS: For the 50-69 year age group, the mean annual breast cancer mortality decline was 0.8% (not significant) for 1988-1994, and 4.4% (p < 0.0001) for 1995-2001. Statistically significant negative associations between breast cancer mortality in 1997-2001 and lagged biennial screening rates were found with the highest significance at a four-year lag for women aged 50-69 years ( p = 0.0003) and also for women aged 50-79 years (p c = 0.0002). From the regression coefficient, a 70% biennial screening rate is associated with 32% lower breast cancer mortality (compared to zero screening). CONCLUSIONS: The effect of population-based mammography screening on breast cancer mortality in NSW inferred using this method is consistent with results of trials and other service studies. This suggests that population-based mammography screening programs can achieve significant reductions in breast cancer mortality with adequate participation.     

Comparison of Mammography in Combination with Breast Ultrasonography Versus Mammography Alone for Breast Cancer Screening in Asymptomatic Women

Aim: To compare the agreement of screening breast mammography plus ultrasound and reviewedmammography alone in asymptomatic women. Materials and Methods: All breast imaging data were obtained forwomen who presented for routine medical checkup at National Cancer Institute (NCI), Thailand from January2010 to June 2013. A radiologist performed masked interpretations of selected mammographic images retrievedfrom the computer imaging database. Previous mammography, ultrasound reports and clinical data were blindedbefore film re-interpretation. Kappa values were calculated to assess the agreement between BIRADS assessmentcategory and BIRADS classification of density obtained from the mammography with ultrasound in imagingdatabase and reviewed mammography alone. Results: Regarding BIRADS assessment category, concordancebetween the two interpretations were good. Observed agreement was 96.1%. There was moderate agreement inwhich the Kappa value was 0.58% (95%CI; 0.45, 0.87). The agreement of BI-RADS classification of density wassubstantial, with a Kappa value of 0.60 (95%CI; 0.54, 0.66). Different results were obtained when a subgroupof patients aged ≥60 years were analyzed. In women in this group, observed agreement was 97.6%. There wasalso substantial agreement in which the Kappa value was 0.74% (95%CI; 0.49, 0.98). Conclusions: The presentstudy revealed that concordance between mammography plus ultrasound and reviewed mammography alonein asymptomatic women is good. However, there is just moderate agreement which can be enhanced if agetargetedbreast imaging is performed. Substantial agreement can be achieved in women aged ≥60. Adjunctivebreast ultrasound is less important in women in this group.     

Breast cancer screening compliance among young women in a free access healthcare system

BACKGROUND AND OBJECTIVES: To examine mammographic screening compliance among young military healthcare beneficiaries and to examine factors related to one time and recent mammographic compliance. METHODS: Medical records were reviewed for 1,073 subjects (age 41-47) recording dates of the two most recent screening mammograms. Examined outcomes were: whether the woman ever had mammography and, if so, whether she had a mammogram within 400 days. Examined predictors were: ethnicity, age, Gail Model risk score, family history, whether the woman knew a young woman with breast cancer, and importance attributed to breast cancer screening. RESULTS: 90.4% of women studied had at least one mammogram. 71.1% underwent screening within 400 days. Rates of ever having mammography were higher for women with family history of breast cancer and Asian, Pacific Islander, Black or Hispanic women. No measured covariate correlated with having mammography within 400 days. CONCLUSIONS: One time screening participation was high in this select group of women for whom cost and access barriers were removed, but was lower with regard to having a recent mammogram. Correlates of ever having and recent mammography are not synonymous.     

Performance measures from 10 years of breast screening in the Ontario Breast Screening Program, 1990/91 to 2000.

Performance measures for the Ontario Breast Screening Program (OBSP) by age group, time period and screening modality from 10 years of breast screening were evaluated. Data were available from routine information collected on 283,962 women aged 50 to 69 screened at 73 screening centres between 1 July 1990 and 31 December 2000. Although, initially, participation in the OBSP was low, this rate increased over time and the majority of women screened returned for subsequent screening. Abnormal call rates increased slightly over the time period, were higher in women aged 50 to 59, and for women with mammographic abnormalities. Detection rates of invasive cancer were higher and prognostic features of cancers were better for women age 60 to 69, and those referred by mammography. Along with the prognostic features of cancers, the benign to malignant surgical ratio and diagnostic interval improved over the time periods and for women aged 60 to 69. Greater proportions of women had shorter diagnostic intervals and were more likely to have a diagnosis of breast cancer after surgery if they were referred by both clinical breast examination and mammography. Although some enhancements of the programme are necessary, the OBSP met or exceeded Canadian targets for most performance measures.     

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.     

Breast density as a predictor of mammographic detection: comparison of interval- and screen-detected cancers

BACKGROUND: Screening mammography is the best method to reduce mortality from breast cancer, yet some breast cancers cannot be detected by mammography. Cancers diagnosed after a negative mammogram are known as interval cancers. This study investigated whether mammographic breast density is related to the risk of interval cancer. METHODS: Subjects were selected from women participating in mammographic screening from 1988 through 1993 in a large health maintenance organization based in Seattle, WA. Women were eligible for the study if they had been diagnosed with a first primary invasive breast cancer within 24 months of a screening mammogram and before a subsequent one. Interval cancer case subjects (n = 149) were women whose breast cancer occurred after a negative or benign mammographic assessment. Screen-detected control subjects (n = 388) were diagnosed after a positive screening mammogram. One radiologist, who was blinded to cancer status, assessed breast density by use of the American College of Radiology Breast Imaging Reporting and Data System. RESULTS: Mammographic sensitivity (i.e., the ability of mammography to detect a cancer) was 80% among women with predominantly fatty breasts but just 30% in women with extremely dense breasts. The odds ratio (OR) for interval cancer among women with extremely dense breasts was 6.14 (95% confidence interval [CI] = 1.95-19.4), compared with women with extremely fatty breasts, after adjustment for age at index mammogram, menopausal status, use of hormone replacement therapy, and body mass index. When only those interval cancer cases confirmed by retrospective review of index mammograms were considered, the OR increased to 9.47 (95% CI = 2.78-32.3). CONCLUSION: Mammographic breast density appears to be a major risk factor for interval cancer.     

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.     

Performance of diagnostic mammography for women with signs or symptoms of breast cancer

BACKGROUND: The performance of diagnostic mammography for women with signs or symptoms of breast cancer has not been well studied. We evaluated whether age, breast density, self-reported breast lump, and previous mammography influence the performance of diagnostic mammography. METHODS: From January 1996 through March 1998, prospective diagnostic mammography data from women aged 25-89 years with no previous breast cancer were linked to cancer outcomes data in six mammography registries participating in the Breast Cancer Surveillance Consortium. We used the final mammographic assessment at the end of the imaging work-up to determine abnormal mammographic examination rate, positive predictive value (PPV), sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve. We used age, breast density, prior mammogram, and self-reported breast lump jointly as predictors of performance. All statistical tests were two-sided. RESULTS: Of 41 427 diagnostic mammograms, 6279 (15.2%) were judged abnormal. The overall PPV was 21.8%, sensitivity was 85.8%, and specificity was 87.7%. Multivariate analysis showed that sensitivity and specificity generally declined as breast density increased (P =.007 and P<.001, respectively), that previous mammography decreased sensitivity (odds ratio [OR] = 0.52, 95% confidence interval [CI] = 0.36 to 0.74; P<.001) but increased specificity (OR = 1.43, 95% CI = 1.31 to 1.57; P<.001), and that a self-reported breast lump increased sensitivity (OR = 1.64, 95% CI = 1.13 to 2.38; P =.013) but decreased specificity (OR = 0.54, 95% CI = 0.49 to 0.59; P<.001). ROC analysis showed that higher breast density and previous mammography were negatively related to accuracy (P<.001 for both). CONCLUSIONS: Diagnostic mammography in women with signs or symptoms of breast cancer shows higher sensitivity and lower specificity than screening mammography does. Higher breast density and previous mammographic examination appear to impair performance.     

Successful First Round Results of a Turkish Breast Cancer Screening Program with Mammography in Bahcesehir,Istanbul

Background: The Bahcesehir Breast Cancer Screening Project is the first organized population basedbreast cancer mammographic screening project in Turkey. The objective of this prospective observationalstudy was to demonstrate the feasibility of a screening program in a developing country and to determine theappropriate age (40 or 50 years old) to start with screening in Turkish women. Materials and Methods: BetweenJanuary 2009 to December 2010, a total of 3,758 women aged 40-69 years were recruited in this prospectivestudy. Screening was conducted biannually, and five rounds were planned. After clinical breast examination(CBE), two-view mammograms were obtained. True positivity, false positivity, positive predictive values (PPV)according to ACR, cancer detection rate, minimal cancer detection rate, axillary node positivity and recall ratewere calculated. Breast ultrasound and biopsy were performed in suspicious cases. Results: Breast biopsy wasperformed in 55 patients, and 18 cancers were detected in the first round. The overall cancer detection rate was4.8 per 1,000 women. Most of the screened women (54%) and detected cancers (56%) were in women aged 40-49. Ductal carcinoma in situ (DCIS) and stage I cancer and axillary node positivity rates were 22%, 61%, and16.6%, respectively. The positive predictivity for biopsy was 32.7%, whereas the overall recall rate was 18.4 %.Conclusions: Preliminary results of the study suggest that population based organized screening are feasibleand age of onset of mammographic screening should be 40 years in Turkey.     

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.     

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.     

Varying Levels of Family History of Breast Cancer in Relation to Mammographic Breast Density (United States)

Objective We examined the relationship between breast cancer family history and mammographic breast density. Methods Participants included 35,019 postmenopausal women aged ≥40 years enrolled in a population-based mammography screening program. We collected data on the number and type of 1st and 2nd degree female relatives with a history of breast cancer and their ages at diagnosis. We used the Breast Imaging Reporting and Data System™ breast density categories to identify women with fatty (1 = almost entirely fatty or 2 = scattered fibroglandular tissue) and dense (3 = heterogeneously dense or 4 = extremely dense) breasts. We used logistic regression to calculate odds ratios (OR) and 95% confidence intervals for dense (N = 18,111) compared to fatty breasts (N = 16,908). Results The odds of having dense breasts were 17% greater for women with affected 1st degree relatives than women with no family history. The odds increased with more affected 1st degree relatives [≥3 vs. none (OR = 1.46; 1.05–2.01)] and among women with ≥1 affected 1st degree relative diagnosed <50 years (OR = 1.22; 1.10–1.34). Conclusions Having a family history of breast cancer was more strongly associated with mammographic breast density when the affected relatives were more genetically similar. There may be common, yet undiscovered, genetic elements that affect breast cancer and mammographic breast density. Financial Support: This study was supported by grant CA063731 from the National Cancer Institute.     

Effectiveness of Mammographic Screening for Breast Cancer in Women Aged over 50 Years in Japan

The optimal age for effective screening of subjects for breast cancer by mammography in Japan was studied based on the results of two mammograpbic screening systems (systems I and II) in Tokushima Prefecture, System I consisted of visit screening using a bus equipped with a mammographic apparatus. System II consisted of central screening performed at Tokushima Health Screening Center. The examinees numbered 2,500 and 3,707 in systems I and II, respectively. There was a significant difference between the two screening systems in the age distribution of the examinees. The detection rates of breast cancer were 0.6% and 0.24% in systems I and II, respectively, which are 2–5 times higher than that (0.12%) obtained by conventional screening using physical examination alone. The detection rate increased especially in the sixth and seventh decades of life. The sensitivity of mammography screening was 93.3% in system I and 81.1% in system II. Higher sensitivity (100%) than that (73%) of screening by physical examination was obtained in women aged over 50. The proportion of stage I was 60% in system I and 66.7% in system II, compared with 32–65% in the United States and Europe. The rates of no nodal involvement were high, being 77.8% and 83.3% in systems I and II, respectively, compared with 57–71% in other countries. Breast-conserving therapy was applied to 18 of the 24 patients with breast cancer detected by the two screening systems. In addition, in Wolfe's classification of mammograms, the proportion of DY (mammary dysplasia) pattern was remarkably low, being 3.2% in the sixth decade and 0.8% in the seventh decade, compared with 16.6% in women aged 49 years. These results indicate that mammographic screening is effective in women aged over 50 years in Japan, as has been found in other countries.     

The role of mammography in breast cancer prevention.

Screening mammography has been shown to reduce breast cancer mortality by detecting small, nonpalpable, early-stage breast cancers. In 1998, several studies were published, reinforcing the value of screening mammography in women aged 40 years and older. Some studies focused on when screening should begin (age 40 years), while others analyzed the process of screening mammography, with particular attention to recall rates and false-positive studies. Other reports emphasized the limitations of mammographic interpretation, the use of computers to aid in mammographic diagnosis, and screening with ultrasound.     

中国妇女乳腺X线钼靶摄影普查成本效益分析

目的:分析中国妇女乳腺X线钼靶摄影普查的成本效益.方法:结合中国妇女的人群年龄结构以及乳腺癌相关数据,利用Markov模型模拟乳腺癌发展过程,结合每一种状态的成本消耗和健康收益,通过10个周期(每个周期为1年)的循环运算,分析乳腺X线钼靶摄影普查的成本效益.结果:35～59岁人群的普查增量成本效益比(incremental cost-effectiveness ratio,ICER)为216 656.00元/质量调整生命年(quality adjusted life year,Q ALY),普查可降低乳腺癌死亡率14.66％; 35～69岁人群的普查ICER为248727.50元/QALY,普查可降低乳腺癌死亡率14.79％.ICER与乳腺癌发病率、X线钼靶摄影检查的敏感度和特异度以及检查费用等密切相关.结论:中国女性采用乳腺癌普查可降低乳腺癌死亡率约15％.根据当前中国女性乳腺癌发病率、普查平均效能(敏感度和特异度)以及检查成本,全国乳腺癌普查暂不具成本效益.鉴于普查的成本效益与发病率、普查效能以及普查中的检查价格密切相关,因此随着乳腺癌发病率的提高、普查中检查价格的降低以及普查敏感度或特异度的提高,中国妇女的乳腺癌普查将具有成本效益甚至极具成本效益.