Mammography Screening Program Research Articles

No clear effect of postoperative radiotherapy on survival of breast cancer patients with one to three positive nodes: a population-based study

In published radiotherapy trials, the failure rate in the control arm among patients with one to three positive nodes is high compared with that seen with modern adjuvant treatments. Therefore, the generalizability of the results has been questioned. The aim of the present study was to compare relative survival in breast cancer patients between two Swedish regions with screening mammography programs and adjuvant treatment guidelines similar with the exception of the indication of radiotherapy for patients with one to three positive nodes. Between 1989 and 2006, breast cancer patients were managed very similarly in the west and southeast regions, except for indication for postoperative radiotherapy. In patients with one to three positive nodes, postmastectomy radiotherapy was generally given in the southeast region (89% of all cases) and generally not given in the west region (15% of all cases). For patients with one to three positive nodes who underwent breast-conserving surgery, patients in the west region had breast radiotherapy only, while patients in the southeast region had both breast and lymph nodes irradiated. The 10-year relative survival for patients with one to three positive lymph nodes was 78% in the west region and 77% in the southeast region (P = 0.12). Separate analyses depending on type of surgery, as well as number of examined nodes, also revealed similar relative survival. Locoregional postoperative radiotherapy has well-known side-effects, but in this population-based study, there was little or no influence of this type of radiotherapy on survival when one to three lymph nodes were involved.

Comparison of cumulative false-positive risk of screening mammography in the United States and Denmark

IntroductionIn the United States (US), about one-half of women screened with annual mammography have at least one false-positive test after ten screens. The estimate for European women screened ten times biennially is much lower. We evaluate to what extent screening interval, mammogram type, and statistical methods, can explain the reported differences. MethodsWe included all screens from women first screened at age 50–69 years in the US Breast Cancer Surveillance Consortium (BCSC) (n=99,455) between 1996–2010, and from two population-based mammography screening programs in Denmark (n=230,452 and n=400,204), between 1991–2012 and 1993–2013, respectively. Model-based cumulative false-positive risks were computed for the entire sample, using two statistical methods (Hubbard Njor) previously used to estimate false-positive risks in the US and Europe. ResultsEmpirical cumulative risk of at least one false-positive test after eight (annual or biennial) screens was 41.9% in BCSC, 16.1% in Copenhagen, and 7.4% in Funen. Variation in screening interval and mammogram type did not explain the differences by country. Using the Hubbard method, the model-based cumulative risks after eight screens was 45.1% in BCSC, 9.6% in Copenhagen, and 8.8% in Funen. Using the Njor method, these risks were estimated to be 43.6, 10.9 and 8.0%. ConclusionChoice of statistical method, screening interval and mammogram type does not explain the substantial differences in cumulative false-positive risk between the US and Europe.

Blinded Anonymization: a method for evaluating cancer prevention programs under restrictive data protection regulations.

Evaluating cancer prevention programs requires collecting and linking data on a case specific level from multiple sources of the healthcare system. Therefore, one has to comply with data protection regulations which are restrictive in Germany and will likely become stricter in Europe in general. To facilitate the mortality evaluation of the German mammography screening program, with more than 10 Million eligible women, we developed a method that does not require written individual consent and is compliant to existing privacy regulations. Our setup is composed of different data owners, a data collection center (DCC) and an evaluation center (EC). Each data owner uses a dedicated software that preprocesses plain-text personal identifiers (IDAT) and plaintext evaluation data (EDAT) in such a way that only irreversibly encrypted record assignment numbers (RAN) and pre-aggregated, reversibly encrypted EDAT are transmitted to the DCC. The DCC uses the RANs to perform a probabilistic record linkage which is based on an established and evaluated algorithm. For potentially identifying attributes within the EDAT ('quasi-identifiers'), we developed a novel process, named 'blinded anonymization'. It allows selecting a specific generalization from the pre-processed and encrypted attribute aggregations, to create a new data set with assured k-anonymity, without using any plain-text information. The anonymized data is transferred to the EC where the EDAT is decrypted and used for evaluation. Our concept was approved by German data protection authorities. We implemented a prototype and tested it with more than 1.5 Million simulated records, containing realistically distributed IDAT. The core processes worked well with regard to performance parameters. We created different generalizations and calculated the respective suppression rates. We discuss modalities, implications and limitations for large data sets in the cancer registry domain, as well as approaches for further improvements like l-diversity and automatic computation of 'optimal' generalizations.

Opportunistic mammography screening provides effective detection rates in a limited resource healthcare system.

BackgroundBreast cancer is the leading cause of cancer deaths in women world-wide. In low and middle income countries, where there are no population-based mammographic screening programmes, late presentation is common, and because of inadequate access to optimal treatment, survival rates are poor. Mammographic screening is well-studied in high-income countries in western populations, and because it has been shown to reduce breast cancer mortality, it has become part of the healthcare systems in such countries. However the performance of mammographic screening in a developing country is largely unknown.This study aims to evaluate the performance of mammographic screening in Malaysia, a middle income country, and to compare the stage and surgical treatment of screen-detected and symptomatic breast cancer.MethodsA retrospective review of 2510 mammograms performed from Jan to Dec 2010 in a tertiary medical centre is carried out. The three groups identified are the routine (opportunistic) screening group, the targeted (high risk) screening group and the diagnostic group. The performance indicators of each group is calculated, and stage at presentation and treatment between the screening and diagnostic group is analyzed.ResultsThe cancer detection rate in the opportunistic screening group, targeted screening group, and the symptomatic group is 0.5 %, 1.25 % and 26 % respectively. The proportion of ductal carcinoma in situ is 23.1 % in the two screening groups compared to only 2.5 % in the diagnostic group. Among the opportunistic screening group, the cancer detection rate was 0.2 % in women below 50 years old compared to 0.65 % in women 50 years and above. The performance indicators are within international standards. Early-staged breast cancer (Stage 0–2) were 84.6 % in the screening groups compared to 61.1 % in the diagnostic group.ConclusionFrom the results, in a setting with resource constraints, targeted screening of high risk individuals will give a higher yield, and if more resources are available, population-based screening of women 50 and above is effective.Opportunistic mammographic screening is feasible and effective in a middle income country with performance indicators within international standards. Waiting until women are symptomatic will lead to more advanced cancers.

Balance entre riesgos y beneficios del tamizaje mamográfico de cáncer de mama ¿apoyaría su recomendación en mujeres peruanas?

The aim of this study is to assess the balance between benefits and risks of population-based mammography screening programs in Peruvian women. We followed the criteria proposed by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) working group. A generic search strategy for published studies was performed using Medline and other sources of national data (gray literature). The evidence of benefits, risks, costs and preferences of the population was used in order to state a recommendation in favour, or against, screening. We found five systematic reviews (SR) that evaluated the balance between benefit and risks, two economic evaluations based on Peruvian data, and one study that reported the preferences of Peruvian women. The quality of evidence of the SR was moderate in favour of screening in women aged 50-69 years. The balance of risks and benefits showed a higher probability of overdiagnosis compared with the reduction in mortality. The most cost-effective strategy was the triennial mammography. Perceived barriers could seriously compromise the participation of women. In conclusion, the recommendation of mammography screening for Peruvian women is weak, even more if we take into account other health necessities of the population. However, if implemented, triennial mammography in women aged 50-69 years could be the more suitable screening strategy.

Does geographic location impact the survival differential between screen- and interval-detected breast cancers?

Although mammography screening programs aim to diagnose breast cancer at an early stage, not all tumours are detected during the regular screening examination. This study examines the influence of various characteristics, including geographical residence, on the survival between screen- and interval-detected breast cancers among participants of a public population-based breast screening program in Queensland, Australia. The investigation was performed using the linked population-based datasets from BreastScreen Queensland and the Queensland Cancer Registry for the period of 1997–2008 for women aged 40–89 years at diagnosis. A Bayesian spatial relative survival modelling approach that accommodates rare outcomes in small geographic regions was adopted, with the use of Markov chain Monte Carlo computation, to evaluate the relative excess risk of breast cancer. In the multivariate Bayesian spatial model, higher relative excess risk of mortality was observed in interval-detected cancer (RER = 1.59, 95 % credible interval = [1.33, 1.89]) compared to screen-detected cancer. Higher cancer survival among the study cohort was also observed among younger women (40–59 years), those of non-Indigenous ethnicity, with localised (stage I) tumour stage as well as those not in the work force. There was no independent association with marital status. Moreover, there was no substantive evidence of either measured geographical or latent random spatial inequalities in survival among screening participants across Queensland, meaning the higher survival for screen-detected breast cancer patients compared to interval-detected women was consistent across the state. These results provide suggestive evidence supporting the effectiveness of the BreastScreen Queensland screening program in reaching socio-economically disadvantaged women as well as those living in rural and remote areas of the state, but also highlights the need for any interval cancer awareness programs to be geographically widespread.

Mammography screening in three Finnish residential areas: comprehensive population-based study of breast cancer incidence and incidence-based mortality 1976-2009.

Background:The aim of this study was to evaluate the effectiveness of a large-scale screening programme for breast cancer (BC) in Turku, Finland. Incidence and incidence-based mortality (IBM) figures were compared with the areas applying different screening policies.Methods:Deaths and person-time of women aged 40–84 were assessed for the period 1976–1986 (prescreening era) and the periods 1987–1997 and 1998–2009 (screening periods) using incidence and IBM by age at diagnosis and at death. There was a total of 40.7 million women-years, 83 497 invasive BCs obtained from the Finnish Cancer Registry; 17 508 BC deaths were linked with the data from Statistics Finland.Results:In Turku, a significant (> 20%) reduction in IBM occurred during 1987–2009 among women aged 60–74 years at diagnosis compared with Helsinki (IBMRR: 0.75, 95% CI: 0.57–1.00), and in women aged 75–84 years at death compared with the rest of Finland (IBMRR: 0.72, 95% CI: 0.53–0.96).Conclusions:The wide mammography screening programme in Turku was effective in decreasing BC mortality in the elderly age groups. These results support the implementation of BC screening from age 50 up to 74 years.

Breast cancer screening: world experience and prospects

Breast cancer screening (breast examination in potentially healthy women for early, preclinical detection of malignancies) was introduced in the 60s last century in the United States, and then in the number of countries in the world. Many years of experience has shown important clinical and prognostic value of mammographic screening programs for increasing the proportion of carcinoma in situ and breast cancer stage I, which led to significant improvement in the long-term survival. The review presents the main stages of the screening programs, differences in the organization of screening in different countries, and also gives the definition of «screening age,» high-risk factors for breast cancer appearing and possible intensification of early detection programs. The existing screening methods have described, their advantages and disadvantages, as well as highlighted possible areas for screening programs.

Digital mammography screening in Germany: Impact of age and histological subtype on program sensitivity

IntroductionProgram sensitivity (PS), i.e., the ratio of screen-detected cancers divided by the sum of screen-detected plus interval cancers, is a major outcome in population-based mammography screening programs (MSP). This study evaluated PS within the digital MSP in Germany focussing on the impact of age and histological subtype. MethodsData of 838,579 first-time participants aged 50–69 years who were screened in 2005–2008 were linked with cancer registry data from Germany's most populous state, North Rhine-Westphalia. Invasive breast cancers and ductal carcinomas in situ (DCIS) were detected either at screening or during the 24 month post-screening interval. PS was evaluated with respect to age at screening, in-situ or invasive cancer and histological characteristics. ResultsIn total, 6767 cancers were detected at screening and 1884 cancers were diagnosed during the post-screening interval. The overall PS amounted to 78.2% and increased from 72.1% at age 50–54 years to 82.4% at age 65–69 years (p for trend <0.0001). PS was higher for non-lobular (79.1%) than lobular carcinomas (72.1%, p < 0.0001). The highest PS was observed in DCIS across all ages (>90%), while PS was lowest among participants aged 50–54 years with invasive breast cancer (67.7%), particularly among those with lobular subtype (62.8%). Interval cancers showed generally more advanced tumour stages. ConclusionsWhile overall PS was high, differences across subgroups indicated that youngest screening participants are at higher risk of interval cancer. Age-adapted recall and assessment strategies in younger participants may need to be considered to improve PS in younger women.

Measuring the burden of interval cancers in long-standing screening mammography programmes.

Mammography screening programme sensitivity is evaluated by comparing the interval cancer rate (ICR) with the expected breast cancer incidence without screening, ie. the proportional interval cancer rate (PICR). The PICR is usually found by extrapolating pre-screening incidence rates, whereas ICR is calculated from data available in the screening programmes. As there is no consensus regarding estimation of background incidence, we seek to validate the ICR measure against the PICR. Screening data from the three mammography screening programmes of Stockholm, Copenhagen, and Funen in the period 1989-2011 provided data to calculate the ICR. The most commonly described methods of extrapolating pre-screening incidence rates to calculate the PICR were illustrated and PICRs were calculated by year and programme using these different methods and compared with the ICRs. PICRs varied greatly, reaching a difference of 32-34% in Stockholm, 79% in Copenhagen, and 100-106% in Funen between the highest and the lowest value, depending on which method was applied. PICRs exhibited large variations yearly and from programme to programme. ICRs did not vary to the same extent, ranging on average from 0.100 to 0.136 in the first 12-months and between 0.201 and 0.225 in the last 12-months of the two-year period after a negative screen across the three programmes. The value of the PICR is hugely influenced by which method is applied, whereas the ICR is calculated purely on data available within programmes. We find that the PICR, the establishing indicator for sensitivity, could preferably be replaced by the ICR.

Health-related lifestyle factors and mammography screening attendance in a Swedish cohort study.

To determine whether health-related lifestyle factors are associated with attendance at a population-based invitational mammography screening program in southern Sweden, data on health-related lifestyle factors (smoking, alcohol use, physical activity, BMI, diet, self-rated health, and stress) were obtained from the Malmö Diet and Cancer Study and linked to the Malmö mammography register (Sweden, 1992-2009). Women (n=11 409) who were free from breast cancer at study entry were included in the cohort, and mammography attendance was followed from cohort entry to 31 December 2009. Generalized estimating equations were used to account for repeated measures within patients. Adjusted odds ratios (OR) and 95% confidence intervals (CI) are reported. Nonattendance occurred in 8% of the 69 746 screening opportunities that were observed. Nonattendance was more common among women who were current or former smokers [OR=1.60 (1.45-1.76) and OR=1.15 (1.05-1.28)], had not used alcohol in the past year [OR=1.55 (1.32-1.83)], were less physically active outside of work [OR=1.10 (1.00-1.20)], had high physical activity at work (OR=1.13, 95% CI: 1.00-1.28), were vegetarians or vegans [OR=1.49 (1.11-1.99)], had not used dietary supplements [OR=1.11 (1.01-1.21)], had poor self-rated health [OR=1.24 (1.14-1.36)], and were experiencing greater stress [OR=1.25 (1.14-1.36)]. In this cohort, nonattendance was associated with smoking, alcohol abstinence, physical activity, poor self-rated health, stress, and following a vegetarian/vegan diet. These findings generally support the notion that women with less healthy lifestyles are less likely to engage in mammography screening.

Cultuurafhankelijke beoordeling van leeftijdsgrenzen voor mammografisch screeningsonderzoek

Abstract Culture dependent appraisal of age thresholds for mammographic screening; the effectiveness of health communication in cross-cultural perspectiveIn previous empirical studies it was found that Dutch women could hardly be convinced by experimental health communication leaflets in which they were dissuaded to participate in systematic mammographic screening programs when they are younger than 50. In contrast, the far majority of the Dutch experimental participants accepted with enthusiasm the standpoint that women above 50 should go for a breast cancer screening every other year. The empirical research presented in this article is a replication of the Dutch studies, but now conducted in Ticino (Switzerland). Ticino is a culture that is quite different from Holland regarding the nature of preventive screening on breast cancer: systematic screening in Holland versus opportunistic screening in Ticino. Moreover, in Ticino the mass media pay far less attention to issues concerning breast cancer compared with those in Holland. As predicted, the Swiss participants were more susceptible for the persuasive attempts and experimental manipulations in the health communication leaflets.

Implementation of Performance Indicators in the Czech Breast Cancer Screening Programme – Results of the Regular Monitoring

The Czech organised breast cancer screening programme was initiated in 2002. Collection of data on screening mammography examinations, subsequent diagnostic procedures, and final dia-gnosis is an indispensable part of the programme. Data collection is obligatory for all accredited centres, in accordance with regulations issued by the Czech Ministry of Health. This contribution aims to demonstrate the recent results of quality monitoring of the accredited centres. Quality indicators, whose definition complies with international standards, involve the women's participation, the volume of performed examinations, the accuracy of screening mammography, the use of preoperative diagnostics, and the proportion of early detected tumours. Our evaluation documents a continuous improvement in quality of the Czech mammography screening programme, which is thereby in full agreement with international recommendations on quality assurance.

Is mammography screening history a predictor of future breast cancer risk?

Inspired by the model by Walter and Day for risk of cervical cancer following negative screens, one might hypothesize that women in a mammography screening programme with a certain number of negative screens had a lower remaining breast cancer risk than that of women in general. We studied whether number of negative screens was a predictor for a low remaining breast cancer risk in women participating in the mammography screening programmes in Stockholm, Copenhagen and Funen. Data were collected from the mammography screening programmes in Stockholm, Sweden (1989-2012), Copenhagen, Denmark (1991-2009) and Funen, Denmark (1993-2009), and linked to the respective cancer registries. We calculated cumulative hazard rates for breast cancer in women in cohorts defined by age at entry and number of negative screens for the maximum follow-up period in each screening centre. For all centres and cohorts, the cumulative hazard were parallel for all number of negative screens, from after the time, when the women were scheduled to be invited for the next screen. This means that the remaining breast cancer risk is similar no matter how many negative screens a woman have had. Number of negative screens was not a predictor of a low remaining breast cancer risk in women participating in the mammography screening programmes in Stockholm, Sweden, Copenhagen and Funen, Denmark. The history of previous negative screens is therefore not suitable for personalisation of mammography screening.

Symptomatic Breast Cancer Diagnosis and Multimodal Management in Women Aged 40 to 50 Years; Consequences of Current Mammographic Screening Programs

IntroductionConsensus exists that screening mammography is appropriate for women aged 50 to 69 years. However, the effectiveness of such screening for women aged 40 to 50 years is still questioned. The aim of our study was to analyze breast cancer management in the 40- to 50-year age group. We also wished to determine the proportion of patients with a significant family history and whether this was associated with more advanced disease. Patients and MethodsAll female patients with primary breast cancer diagnosed between 40 and 50 years of age were included over a 4-year period. The database of the National Breast Cancer Research Institute was interrogated, and a chart and radiology review carried out to obtain relevant details of clinical presentation, family history, radiological findings, and treatments undertaken. ResultsThree hundred thirty-four patients were diagnosed in this cohort during the study period. Twenty-two percent of those diagnosed had a family history of breast cancer with 1.8% having a genetically confirmed predisposition to breast cancer. A significant proportion of patients presented with advanced disease, with 50% of patients having nodal involvement and 3% who presented with distant metastases. The overall rate of mastectomy was 47%, with minimal variation between the surgeons who performed the surgeries. More than half of the patients in our analysis underwent axillary clearance (51%). ConclusionOur results indicate that a large proportion of patients in the 40- to 50-year age group presented with advanced disease and required aggressive surgical and adjuvant treatment. The presence of a family history did not identify a subgroup with more advanced disease at presentation.

Quality Control of the Hungarian Nationwide Mammography Screening Programme.

Quality Control of the Hungarian Nationwide Mammography Screening Programme.

A simple way to measure the burden of interval cancers in breast cancer screening.

BackgroundThe sensitivity of a mammography program is normally evaluated by comparing the interval cancer rate to the expected breast cancer incidence without screening, i.e. the proportional interval cancer rate (PICR). The expected breast cancer incidence in absence of screening is, however, difficult to estimate when a program has been running for some time. As an alternative to the PICR we propose the interval cancer ratio . We validated this simple measure by comparing it with the traditionally used PICR.MethodWe undertook a systematic review and included studies: 1) covering a service screening program, 2) women aged 50-69 years, 3) observed data, 4) interval cancers, women screened, or interval cancer rate, screen detected cases, or screen detection rate, and 5) estimated breast cancer incidence rate of background population. This resulted in 5 papers describing 12 mammography screening programs.ResultsCovering initial screens only, the ICR varied from 0.10 to 0.28 while the PICR varied from 0.22 to 0.51. For subsequent screens only, the ICR varied from 0.22 to 0.37 and the PICR from 0.28 to 0.51. There was a strong positive correlation between the ICR and the PICR for initial screens (r = 0.81), but less so for subsequent screens (r = 0.65).ConclusionThis alternate measure seems to capture the burden of interval cancers just as well as the traditional PICR, without need for the increasingly difficult estimation of background incidence, making it a more accessible tool when evaluating mammography screening program performance.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2407-14-782) contains supplementary material, which is available to authorized users.

Global challenges of cancer imaging: perspective from different parts of the world: Asia

Asia accounts for about 60% of the world's population and half the global burden of cancer [1]. Due to the diverse economic development across the Asian continent, countries have highly variable health services development and healthcare infrastructure. Thus, there is disparity in access to services, especially resource intensive cancer management. All countries in Asia, except Japan are defined by the UN as 'less developed regions' and this reflects the limited resources in general. This presentation aims to describe the demographic characteristics of cancer in Asia, and highlight the challenges and main advancements of cancer imaging across this region. Lung cancer is the most common cancer in men (35.2/100,000 persons) and breast cancer the most common cancer in women (29.1/100,000 women) in Asia. The incidence rate of breast cancer in Asia is about 1/3 compared to North America (NA) and Western Europe (WE), although it is on a steady rise. However, the five year prevalence rate is manifold lower indicating that in proportion, there are fewer cancer survivors in Asia. With the exceptions of Japan, South Korea and Taiwan, resources in most countries are inadequate for population-based organised screening mammography programmes. However, it is less clear if organised screening would be a cost-effective programme in Asia, due to the lower incidence rate as well as reduced sensitivity of mammography in Asian women with higher density breast tissue [2], and there is evidence that supplemental ultrasound screening increases the sensitivity for cancer detection in women with dense breasts [3]. Notably, in South East Asia (SEA) and East Asia (EA) compared to the rest of the world, the incidences of liver cancer, oesophageal cancer, stomach cancer and nasopharyngeal cancer are relatively high, although on the decline. Liver cancer is the second and third most common cancer in men in SEA and EA respectively, and fifth most common cancer in women. More than 70% of the new cases of liver cancer are from Asia, of which 50% are from China. Recent studies have advanced the use of gadolinium ethoxybenzyl dimeglumine (Gd-EOB-DTPA) enhanced MRI for its superior sensitivity for the detection of hepatocellular carcinoma, especially small tumors [4], and 11C-acetate PET imaging for detection of well-differentiated tumors [5]. Oesophageal cancer is the fifth most common cancer in EA men. Asia accounts to about 75% of new cases, specifically the 'asian oesophageal cancer belt' that extends from Turkey to Mongolia and Western/Northern China. The majority of these are squamous cell carcinoma in histology. Studies have found 18F-Fluorodeoxyglucose (FDG) PET to be useful in disease staging (particularly upstaging), and predictive of outcome of neo-adjuvant chemotherapy and disease survival [6]. Nasopharyngeal carcinoma is the sixth and fourteenth most common cancer in men across SEA and EA respectively. 80% of new cases are from this region, and are focussed around Southern China, Taiwan and SEA. Current research has evaluated the roles of diffusion MRI for tissue characterisation [7] and 18F-FDG PET for prognostication [8]. In recent years the cancer burden in Asia and its developing countries has surged, and is forecasted to continue to rise. Resources for the provision and development of diagnostic imaging which plays an essential role in early detection and management of cancer must be supported and strengthened across the region.

Lessons from the Swiss Medical Board recommendation against mammography screening programs.

Lessons from the Swiss Medical Board recommendation against mammography screening programs.

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

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. 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. 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). 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.