Predicting the cumulative risk of false-positive mammograms

Interventions to improve follow-up of abnormal findings in cancer screening

The potential reduction in morbidity and mortality through cancer screening cannot be realized without receipt of appropriate follow-up care for abnormalities identified via screening. In this paper, the authors critically examine the existing literature on correlates of receipt of appropriate follow-up care for screen-detected abnormalities, as well as the literature on interventions designed to increase rates of receipt of follow-up care. Lessons learned describe what is known and not known about factors that are related to or predict receipt of follow-up care. Similarly, effective interventions to increase follow-up are described and gaps identified. A conceptual model is developed that categorizes the health care system in the United States as comprising four levels: policy, practice, provider, and patient. Some patient-level factors that influence follow-up receipt are identified, but the lack of data severely limit the understanding of provider, practice, and policy-level correlates. The majority of intervention studies to increase follow-up receipt have focused on patient-level factors and have targeted follow-up of abnormal Papanicolaou smears. Insufficient information is available regarding the effectiveness of provider, practice, or policy-level interventions. Standard definitions of what constitutes appropriate follow-up are lacking, which severely limit comparability of findings across studies. The validity of various methods of obtaining outcome data has not been clearly established. More research is needed on interventions targeting provider, system, and policy-level factors, particularly interventions focusing on follow-up of colorectal and breast abnormalities. Standardization of definitions and measures is needed to facilitate comparisons across studies.

Probability modeling applied to CAD systems for mammography

A practical model based on basic probability theory is developed to evaluate the operational and financial performance of mammography systems. The model is intended to be used by decision makers to evaluate overall sensitivity, overall specificity, positive and negative predictive values, and expected cost. As an illustration, computer aided detection (CAD) systems that support a radiologist's diagnosis are compared with standard mammography to determine conditions that would support their use. The model's input parameters include the operational performance of mammography (with and without CAD), the age of the patient, the cost of administering the mammogram and the expected costs associated with false positive and false negative outcomes. Sensitivity analyses are presented that show the CAD system projecting financial benefit over ranges of uncertainty associated with each model parameter.

Banco de imagens mamográficas para treinamento na interpretação de imagens digitais

OBJETIVO: Disponibilizar aos profissionais da radiologia um "software" para treinamento na interpretação de imagens mamográficas em sistemas digitais. MATERIAIS E MÉTODOS: Foi desenvolvido um "software" em Delphi associado a uma base de dados em Interbase, com a finalidade de armazenar imagens de exames mamográficos associados aos seus laudos em categorias BI-RADS®. As imagens foram previamente qualificadas e digitalizadas em "scanner" a laser Lumiscan 75. O treinamento se faz com imagens apresentadas em monitores comerciais de 17 polegadas, no tamanho 18 × 24 cm. O "software" permite visualizar cada projeção das mamas individualmente, médio-lateral oblíqua e crânio-caudal, ou as quatro imagens simultaneamente. Permite acessar as imagens e os laudos existentes ou interpretar as imagens utilizando o sistema de categorias BI-RADS®, em que o "software" compara o laudo do usuário com as informações do banco de dados, apontando acertos e erros da interpretação. RESULTADOS: O usuário adquire familiaridade com sistemas digitais, laudos em categorias BI-RADS® e aspectos de qualidade do processo gerador das imagens relativo à detecção de fibras e microcalcificações. CONCLUSÃO: O "software" disponível na intranet da Universidade Federal de São Paulo é ferramenta valiosa para os profissionais interessados em sistemas digitais.

The cumulative risk of a false-positive recall in the Norwegian Breast Cancer Screening Program

BACKGROUND

Biennial breast cancer screening for women ages 50-69 years is recommended by the World Health Organization. It has been claimed that the cumulative risk of a false-positive recall is a significant disadvantage in breast cancer screening programs. The primary objective of this study was to estimate the cumulative risk of a false-positive recall during a screening period of 20 years in women ages 50-51 years who are screened biennially in a population-based screening program. A secondary objective was to estimate the cumulative risk of undergoing fine-needle aspiration cytology, core needle biopsy, and open biopsy with benign morphology in the same group of women.

METHODS

The Norwegian Breast Cancer Screening Program invites all women ages 50-69 years who reside in the country to a 2-view mammography biennially. A nationwide data base that covers all of the invited women includes individual information about all screening activity. Results from three screening rounds in four counties were the basis for this study. False-positive recalls due to abnormal mammograms among 83,416 women who participated all the 3 screening rounds were the basis for the estimations.

RESULTS

It was calculated that women ages 50-51 years who participate in biennial screening run a cumulative risk of 20.8% for a false-positive recall during a screening period of 2 decades. The cumulative risk of undergoing fine-needle aspiration cytology was estimated at 3.9%, and the risk of undergoing core needle biopsy or open biopsy with benign morphology was 1.5% and 0.9%, respectively.

CONCLUSIONS

False-positive recalls are a disadvantage in a breast cancer screening programs, but the cumulative risk seemed to be acceptable in the Norwegian Breast Cancer Screening Program. It is important to communicate the existence and extent of this risk to the target group.

Epidemiological aspects of cancer screening in Germany

PURPOSE

Since 1971, a statutory early detection programme has operated in Germany which comprises health-insurance-paid annual examinations of the breast, cervix, prostate, rectum, and the skin. Since the programme is conceptualised as opportunistic screening, the attendance rates have been low and only reached about 50% among females and 13% among males by the end of the 1990s. Based on these figures and present knowledge on the efficacy of screening modalities, we assessed past benefits and the future potential of cancer screening in Germany.

METHODS

We used published data on the efficacy of screening procedures and German attendance rates, and internationally available data on incidence and mortality in Germany and, for cervical cancer, in other countries. Incidence and mortality rates have been standardised to the world standard, and screening benefit has been given as the population preventable fraction given in percentage.

RESULTS

The past benefits of the statutory early detection programme ranged around 2.0-6.5%. Since the upper limit was due to generous assumptions regarding efficacy or inclusion of treatment effects, the true value might be closer to the estimates of the effect of cervical cancer screening (2.0-4.7%). The achievable future benefit of exploiting the theoretical potential of more exhaustive screening could provide a further mortality reduction of about 3.4% (50% compliance) or 4.7% (70% compliance).

CONCLUSIONS

Screening partially requires an expensive medical infrastructure and is not without risks for the participants. The overall benefit is critically dependent upon the quality of the programme and its in-time control. Any benefit may be annulled by poor quality while costs are overflowing. Well-organised high-quality screening may be a sound basis for cancer control. To preserve or increase the impact of screening and control its expenses: (a) further research efforts are needed towards new or better targeted screening tools or modalities; (b) the efficacy of new modalities has to be evaluated carefully in advance; (c) the programme has to be reconceptualised as organised screening; (d) in-time quality control based on the collection of the basic performance data must be an intrinsic part of the programme.

Is the promise of cancer-screening programs being compromised? Quality of follow-up care after abnormal screening results

Cancer screening has increased dramatically in the United States, yet in some populations, particularly racial minorities or the poor, advanced disease at diagnosis remains high. One potential explanation is that follow-up of abnormal tests is suboptimal, and the benefits of screening are not being realized. The authors used a conceptual model of access to care and integrated constructs from models of provider and patient health behaviors to review published literature on follow-up care. Most studies reported that fewer than 75 percent of patients received some follow-up care, indicating that the promise of screening may be compromised. They identified pervasive barriers to follow-up at the provider, patient, and health care system levels. Interventions that address these barriers appear to be effective. Improvement of data infrastructure and reporting will be important objectives for policy makers, and further use of conceptual models by researchers may improve intervention development and, ultimately, cancer control.

Estimating the cumulative risk of false positive cancer screenings

BACKGROUND

When evaluating cancer screening it is important to estimate the cumulative risk of false positives from periodic screening. Because the data typically come from studies in which the number of screenings varies by subject, estimation must take into account dropouts. A previous approach to estimate the probability of at least one false positive in n screenings unrealistically assumed that the probability of dropout does not depend on prior false positives.

METHOD

By redefining the random variables, we obviate the unrealistic dropout assumption. We also propose a relatively simple logistic regression and extend estimation to the expected number of false positives in n screenings.

RESULTS

We illustrate our methodology using data from women ages 40 to 64 who received up to four annual breast cancer screenings in the Health Insurance Program of Greater New York study, which began in 1963. Covariates were age, time since previous screening, screening number, and whether or not a previous false positive occurred. Defining a false positive as an unnecessary biopsy, the only statistically significant covariate was whether or not a previous false positive occurred. Because the effect of screening number was not statistically significant, extrapolation beyond 4 screenings was reasonable. The estimated mean number of unnecessary biopsies in 10 years per woman screened is.11 with 95% confidence interval of (.10,.12). Defining a false positive as an unnecessary work-up, all the covariates were statistically significant and the estimated mean number of unnecessary work-ups in 4 years per woman screened is.34 with 95% confidence interval (.32,.36).

CONCLUSION

Using data from multiple cancer screenings with dropouts, and allowing dropout to depend on previous history of false positives, we propose a logistic regression model to estimate both the probability of at least one false positive and the expected number of false positives associated with n cancer screenings. The methodology can be used for both informed decision making at the individual level, as well as planning of health services.

Clinical practice. Mammographic screening for breast cancer

A 44-year-old woman who is a new patient has no known current health problems and no family history of breast or ovarian cancer. Eighteen months ago, she had a normal screening mammogram. She recently read that mammograms may not help to prevent death from breast cancer and that “the patient should decide.” But she does not think she knows enough. She worries that there is a breast-cancer epidemic. What should her physician advise?

Screening mammograms by community radiologists: variability in false-positive rates

BACKGROUND

Previous studies have shown that the agreement among radiologists interpreting a test set of mammograms is relatively low. However, data available from real-world settings are sparse. We studied mammographic examination interpretations by radiologists practicing in a community setting and evaluated whether the variability in false-positive rates could be explained by patient, radiologist, and/or testing characteristics.

METHODS

We used medical records on randomly selected women aged 40-69 years who had had at least one screening mammographic examination in a community setting between January 1, 1985, and June 30, 1993. Twenty-four radiologists interpreted 8734 screening mammograms from 2169 women. Hierarchical logistic regression models were used to examine the impact of patient, radiologist, and testing characteristics. All statistical tests were two-sided.

RESULTS

Radiologists varied widely in mammographic examination interpretations, with a mass noted in 0%-7.9%, calcification in 0%-21.3%, and fibrocystic changes in 1.6%-27.8% of mammograms read. False-positive rates ranged from 2.6% to 15.9%. Younger and more recently trained radiologists had higher false-positive rates. Adjustment for patient, radiologist, and testing characteristics narrowed the range of false-positive rates to 3.5%-7.9%. If a woman went to two randomly selected radiologists, her odds, after adjustment, of having a false-positive reading would be 1.5 times greater for the radiologist at higher risk of a false-positive reading, compared with the radiologist at lowest risk (95% highest posterior density interval [similar to a confidence interval] = 1.17 to 2.08).

CONCLUSION

Community radiologists varied widely in their false-positive rates in screening mammograms; this variability range was reduced by half, but not eliminated, after statistical adjustment for patient, radiologist, and testing characteristics. These characteristics need to be considered when evaluating false-positive rates in community mammographic examination screening.

Breast enhanced scintigraphy testing distinguishes between normal, inflammatory breast changes, and breast cancer: a prospective analysis and comparison with mammography

The detection of breast cancer has primarily focused on anatomic findings, whereas assessment of physiologic information using nuclear imaging has been used for the detection of heart disease. Using this approach, the authors developed a method (breast enhanced scintigraphy test [BEST]) for differentiation of breast tissue by enhancing the delivery of isotope. To determine if this technique could distinguish between normal (Nl), inflammatory changes of the breast (ICB), and breast cancer (CA), 100 women were prospectively studied using BEST imaging, and results were compared with mammography and pathology findings using either biopsy or ductoscopy approaches. Mammography demonstrated a sensitivity and specificity of 69% and 84%, respectively. Using BEST imaging, maximal count activity (MCA) was able to distinguish between Nl, ICB, and CA. The results of 2-tailed t test analysis demonstrated statistically significant differences between Nl and ICB MCA (P </=.001); ICB and CA MCA(P </=.001); and N1 and CA MCA(P </=.001). Using MCA results obtained via BEST imaging, breast tissue was able to be differentiated, whereas mammography was able to detect breast cancer in only 69% of cases and incorrectly identified cancer in 16% of cases.

Screening mammography: proven benefit, continued controversy

Screening mammography, despite its limitations, remains the best means for diagnosing breast cancer in asymptomatic women. Regarding the continuing controversies concerning the age at which screening should start, evidence supports beginning regular screening at age 40 in women at average risk . Similarly, evidence suggests that the screening interval should be yearly, especially in younger women. Rather than an arbitrary age at which screening should stop, the decision on screening elderly women should be made on an individual basis, taking into account level of health and life expectancy. More work needs to be done on determining the optimum screening strategies for high-risk women. As to the interpretation of screening mammography, a certain level of observer variability and of false-negative and false-positive readings are inherent in the process. These should be kept to a minimum through efforts by the interpreting radiologist to improve performance through auditing of individual results and continuing education. The impact of double reading and computer-aided detection in the interpretation of screening mammograms warrants further evaluation in terms of efficacy and cost-effectiveness. Despite these continuing controversies, mortality from breast cancer in the United States has been decreasing steadily for the past 25 years. The magnitude of the decrease has been reported to range from 8% to 25%. Although some of this decrease may be attributable to improvements in the treatment of breast cancer, early detection through screening mammography has undoubtedly played a role in this mortality reduction. The controversies that surround the issue of screening should not detract from the fact that screening mammography has proved to save lives.

Dangers and unreliability of mammography: breast examination is a safe, effective, and practical alternative

Mammography screening is a profit-driven technology posing risks compounded by unreliability. In striking contrast, annual clinical breast examination (CBE) by a trained health professional, together with monthly breast self-examination (BSE), is safe, at least as effective, and low in cost. International programs for training nurses how to perform CBE and teach BSE are critical and overdue.

How consistently do women report lifetime mammograms at successive interviews?

BACKGROUND

Little data exist on the reliability of self-reported regular mammography use measures. We used data from two successive interviews of 892 women aged 50 to 74 years without a history of abnormal mammograms to investigate how consistently women report their lifetime number of mammograms.

METHODS

We added an estimated number of mammograms obtained between interviews to the baseline report to create a revised baseline report for comparison with the follow-up report. We then examined the correlation in paired reports, the level of agreement between paired reports, and factors associated with consistent reporting.

RESULTS

Spearman rank correlation between paired reports was 0.73. Agreement between paired reports dropped with increasing lifetime number of mammograms. After adjustment for mammography use, women's characteristics did not appear to be strongly associated with consistent reporting.

CONCLUSIONS

Self-reported lifetime number of mammograms is a reasonably consistent measure for younger women or women with less mammography experience, but it is less reliable for women with long mammography histories. In these women, it may be useful to distinguish those who obtain regular screening from those who do not. Assessing reliability as well as validity for other measures of regular mammography use will allow additional measures to be identified.

Primary and secondary prevention in the reduction of cancer morbidity and mortality

Overall, cancer is a highly preventable disease. Indeed, modifiable external factors, discovered by epidemiological studies during the last 50 years, account for a majority of all cancer deaths. In this review, we discuss briefly these factors and their contribution to the current burden of cancer with an emphasis on the developed countries. Needless to say, tobacco smoking remains the largest contributor to the cancer landscape, whilst the contribution of poor diet and obesity may be equally important, but much more difficult to quantify. Our main goal was to assess what prevention of cancer has accomplished and might accomplish in the next two decades. Based on (necessarily crude) estimates, age-adjusted mortality rates from cancer in year 2000 had been reduced by approximately 13% due to primary prevention and an additional 6% due to the combined effect of early diagnosis and screening (secondary prevention). According to a realistic goal for the year 2020, a further 29% reduction might be achieved by primary, and 4% by secondary prevention. The main contribution to such accomplishments would be a reduction in tobacco smoking, improvements in diet--including reduced alcohol intake--and arrest of the obesity epidemic, in part through increased physical exercise. Rather than being granted, these goals require great effort and major commitment from all those who share responsibility for public health.

Risk-reduction mastectomy: clinical issues and research needs

Risk-reduction mastectomy (RRM), also known as bilateral prophylactic mastectomy, is a controversial clinical option for women who are at increased risk of breast cancer. High-risk women, including women with a strong family history of breast cancer and BRCA1/2 mutation carriers, have several clinical options: risk-reduction surgery (bilateral mastectomy and bilateral oophorectomy), surveillance (mammography, clinical breast examination, and breast self-examination), and chemoprevention (tamoxifen). We review research in a number of areas central to our understanding of RRM, including recent data on 1) the effectiveness of RRM in reducing breast cancer risk, 2) the perception of RRM among women at increased risk and health-care providers, 3) the decision-making process for follow-up care of women at high risk, and 4) satisfaction and psychological status after surgery. We suggest areas of future research to better guide high-risk women and their health-care providers in the decision-making process.

Medical surveillance after breast cancer diagnosis

OBJECTIVES

To characterize the tests ordered for surveillance of breast cancer recurrence in the 4 years after breast cancer diagnosis by surgeons, medical oncologists, and radiation oncologists.

RESEARCH DESIGN

303 stage I or II breast cancer patients age 55-years or older and diagnosed at 1 of 5 Boston hospitals. Patient interviews and medical record abstracts provided the data to characterize patient demographics, the breast cancer stage and its primary therapy, and the surveillance procedures ordered.

RESULTS

279 of the 303 women had some surveillance testing. Among those who received some surveillance, a mean of 22.0 tests were ordered, most by their medical oncologists (mean = 14.4), followed by their surgeons (mean = 9.7) and their radiation oncologists (mean = 5.7). The most common test was a mammogram (mean = 3.9). Women ages 75 to 90 years old were at higher risk for failure to complete four consecutive years of surveillance and for receipt of less than guideline surveillance. Younger women, women treated at a breast cancer center with a unified patient chart, and women who worked full or part time were at lower risk for failure to complete 4 years of surveillance.

CONCLUSION

Most women in this cohort received some surveillance after completing primary therapy for breast cancer. Although no woman's surveillance corresponded exactly to existing guidelines, the oldest women were least likely to receive guideline surveillance. Surveillance after breast cancer therefore joins the list of aspects of breast cancer care-breast cancer screening, diagnosis, prognostic evaluation, and primary therapy-for which older women receive less than definitive care.