Predicting the cumulative risk of false-positive mammograms

Effect of start age of breast cancer screening mammography on the risk of false-positive results

OBJECTIVE

To estimate the false-positive (FP) risk according to the start age of mammography screening (45-46 or 50-51 years).

METHOD

Data from eight regions of the Spanish breast cancer screening programme from 1990 to 2006 were included (1,565,364 women). Discrete time-hazard models were used to ascertain the effect of age and time-related, programme-related and personal variables on FP leading to any further procedure and to invasive procedures (FPI). In a subset we estimated the differential FP risk of starting screening at 45-46 years (175,656 women) or 50-51 (251,275).

RESULTS

A start age of 45-46 versus 50-51 years increased both FP (OR=1.20; 95%CI: 1.13-1.26) and FPI risks (OR=1.43 (95%CI: 1.18-1.73).Other factors increasing FP risk were premenopausal status (FP OR=1.26; 95%CI: 1.23-1.29 and FPI OR=1.22; 95%CI: 1.13-1.31), prior invasive procedures (FP OR=1.52; 95%CI: 1.47-1.57 and FPI (OR=2.08; 95%CI: 1.89-2.28) and family history (FP OR=1.16; 95%CI: 1.12-1.20 and FPI OR=1.26; 95%CI: 1.13-1.41). FP risk was increased by double reading (OR=1.36; 95%CI: 1.23-1.51) and FPI risk by double views (OR=1.34; 95%CI: 1.18-1.52). Both the cumulative FP and FPI risks were higher in women commencing screening at 45-46 years versus 50-51 years (33.30% versus 20.39% and 2.68% versus 1.76%).

CONCLUSIONS

Starting screening earlier increases the cumulative risk of FP and FPI.

Breast cancer genomics: normal tissue and cancer markers

Mammography is a powerful screening tool for early detection of breast cancer, but it has limitations in terms of both specificity and sensitivity. Imaging tools such as MRI that complement mammography are too costly to serve as first-line screens. Recently, progress has been made on blood markers, particularly microRNAs and proteins. There are new methods for protein marker discovery directly in blood, but they are limited in the number of patients that can be examined. An alternative is to discover markers as transcripts in tissues, followed by development of blood protein tests for those that perform best. To identify genes that are overexpressed in malignancy it is paramount to include normal control tissues from healthy individuals. Here we report the identification of potential breast cancer markers, including some that are overexpressed in aggressive disease.

False-positive results in the randomized controlled trial of mammographic screening from age 40 ("Age" trial)

BACKGROUND

False-positive recall is a recognized disadvantage of mammographic breast screening, and the rate of such recalls may be higher in younger women, potentially limiting the value of screening below age 50.

METHODS

Attendance and screening outcome data for 53,884 women in the intervention arm of the U.K. Age trial were analyzed to report observed false-positive recall rates during 13 years of trial fieldwork. The Age trial was a randomized controlled trial of the effect of mammographic screening from age 40 on breast cancer mortality, conducted in 23 National Health Service screening centers between 1991 and 2004. Women randomized to the intervention arm were offered annual invitation to mammography from age 40 or 41 to age 48.

RESULTS

Overall, 7,893 women (14.6% of women the intervention arm and 18.1% of women attending at least one routine screen) experienced one or more false-positive screen during the trial. The rates of false-positive mammography at first and subsequent routine screens were 4.9% and 3.2%, respectively. The cumulative false-positive rate over seven screens was 20.5%. Eighty-nine percent of women who had a false-positive recall at their previous screen attended their next invitation to routine screening.

CONCLUSIONS

The rates of false-positive recall in the Age trial were comparable with the national screening program; however, the positive predictive value of referral was lower. Experiencing a false-positive screen did not seem to lessen the likelihood of re-attendance in the trial.

IMPACT

The question of greatly increased false-positive rates in this age group and of their compromising re-attendance is refuted by the findings of this study.

Cost of breast-related care in the year following false positive screening mammograms

OBJECTIVE

We sought to estimate the direct cost, from the perspective of the health insurer or purchaser, of breast-care services in the year following a false positive screening mammogram compared with a true negative examination.

DESIGN

We identified 21,125 women aged 40 to 80 years enrolled in an integrated healthcare delivery system in Washington State, who participated in screening mammography between January 1, 1998 and July 30, 2002. Pathology and cancer registry data were used to identify breast cancer diagnoses in the year following the screening mammogram. A positive examination was defined as a Breast Imaging Reporting and Data System assessment of 0, 4, or 5. Women with a positive screening mammogram but no breast cancer diagnosed within 1 year were classified as false positives. We used diagnostic and procedure codes in automated health plan data to identify services received in the year following the screening mammogram. Medicare reimbursement rates were applied to all services. We used ordinary least-squares linear regression to estimate the difference in costs following a false positive versus true negative screening mammogram.

RESULTS

False positive results occurred in 9.9% of women; most false positives (87.3%) were followed by breast imaging only. The mean cost of breast-care following a false positive mammogram was $527. This was $503 (95% confidence interval, $490-$515) more than the cost of breast-care services for true negative women.

CONCLUSIONS

The direct costs for breast-related procedures following false positive screening mammograms may contribute substantially to US healthcare spending.

Is surgical excision of core biopsy proven benign papillomas of the breast necessary?

RATIONALE AND OBJECTIVES

The aim of this study was to determine if core biopsy-proven benign papillomas of the breast need to be surgically excised.

MATERIALS AND METHODS

Mammographic and pathologic database review from January 1994 to January 2004 revealed 178 papillary lesions diagnosed by core biopsy in 176 women (mean age, 59 years). All lesions had >or=24 months of imaging follow-up (n = 75) or surgical correlation (n = 103). Details regarding core biopsy technique, lesion appearance, pathologic results, imaging-histopathologic concordance, and follow-up imaging were recorded. Core and surgical pathologic results were correlated.

RESULTS

Of the 178 papillary lesions diagnosed at core needle biopsy, 120 (67%) were initially diagnosed as benign without atypia. The core biopsy diagnoses of benignity were confirmed for all 120 lesions by either surgical excision (n = 45) or stability after >or=2 years of imaging follow-up (n = 75). Of the remaining 58 papillary lesions, 50 were found to be atypical at core needle biopsy; 15 of those 50 (29%) were upgraded to malignancies at surgical excision. Eight of the 178 lesions (5%) were initially diagnosed as malignant papillary lesions at core needle biopsy. Seven of these eight (88%) were confirmed malignant at excision. None of the surgically proven cancers was diagnosed as benign at core biopsy.

CONCLUSIONS

Close imaging follow-up rather than excision of core biopsy-proven benign papillomas was adequate given careful imaging-histopathologic correlation and excision of all atypical and discordant lesions. Individual centers should evaluate their own data and tailor their practices accordingly.

Modelling the cumulative risk of a false-positive screening test

The goal of a screening test is to reduce morbidity and mortality through the early detection of disease; but the benefits of screening must be weighed against potential harms, such as false-positive (FP) results, which may lead to increased healthcare costs, patient anxiety, and other adverse outcomes associated with diagnostic follow-up procedures. Accurate estimation of the cumulative risk of an FP test after multiple screening rounds is important for program evaluation and goal setting, as well as informing individuals undergoing screening what they should expect from testing over time. Estimation of the cumulative FP risk is complicated by the existence of censoring and possible dependence of the censoring time on the event history. Current statistical methods for estimating the cumulative FP risk from censored data follow two distinct approaches, either conditioning on the number of screening tests observed or marginalizing over this random variable. We review these current methods, identify their limitations and possibly unrealistic assumptions, and propose simple extensions to address some of these limitations. We discuss areas where additional extensions may be useful. We illustrate methods for estimating the cumulative FP recall risk of screening mammography and investigate the appropriateness of modelling assumptions using 13 years of data collected by the Breast Cancer Surveillance Consortium (BCSC). In the BCSC data we found evidence of violations of modelling assumptions of both classes of statistical methods. The estimated risk of an FP recall after 10 screening mammograms varied between 58% and 77% depending on the approach used, with an estimate of 63% based on what we feel are the most reasonable modelling assumptions.

Another look at Emergency Department HIV screening in practice: no need to revise expectations

BACKGROUND

A recent study reported a lower than expected specificity and positive predictive value of the rapid oral HIV test in the setting of routine emergency department (ED) screening. These results appeared inconsistent with the findings in another urban Emergency Department during the same time period.

OBJECTIVE

To compare the specificity and positive predictive vale (PPV) of an oral rapid HIV test used in an ED screening program in Washington DC with that performed in the USHER clinical trial.

DESIGN

Period cross-sectional analysis of rapid oral HIV testing conducted in an ongoing HIV screening program emergency department patients.

SETTING

The George Washington University Emergency Department (Washington DC) from 7 February to 1 October 2007.

PATIENTS

1,560 adults seen in the ED for non-HIV-related presenting complaints, who participated in the HIV screening program.

INTERVENTION

Rapid HIV testing with the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test (OraSure Technologies, Bethlehem, Pennsylvania). PATIENTS with reactive rapid test results were offered Western blot testing for confirmation.

MEASUREMENTS

Specificity and positive predictive value for the program were determined. Findings were compared to those found in the USHER trial.

RESULTS

Of 1,560 patients screened for HIV, 13 [0.8%, 95% CI 0.38% to 1.28%] had a reactive HIV screening test, and all were confirmed to be positive by Western Blot. The specificity was 100% (95% CI 99.6%-100%).

LIMITATION

Since non-reactive tests were not confirmed, the test sensitivity cannot be determined.

CONCLUSION

Review of our data conflict with findings from the USHER study surrounding false positive OraQuick HIV screening. Our data suggest that rapid HIV screening protocols implemented in EDs outside of the clinical trial paradigm perform effectively without an excess of false positive results. Compared with other screening tests, HIV rapid screening should remain an essential component of ED practice.

A model of the influence of false-positive mammography screening results on subsequent screening

Decades of empirical research have demonstrated psychological and behavioural consequences of false-positive medical tests. To organise this literature and offer novel predictions, we propose a model of how false-positive mammography results affect return for subsequent mammography screening. We propose that false-positive mammography results alter how women think about themselves (e.g., increasing their perceived likelihood of getting breast cancer) and the screening test (e.g., believing mammography test results are less accurate). We further hypothesise that thoughts elicited by the false-positive experience will, in turn, affect future use of screening mammography. In addition, we discuss methodological considerations for statistical analyses of these mediational pathways and propose two classes of potential moderators. While our model focuses on mammography screening, it may be applicable to psychological and behavioural responses to other screening tests. The model is especially timely as false-positive medical test results are increasingly common, due to efforts to increase uptake of cancer screening, new technologies that improve existing tests' ability to detect disease at the cost of increased false alarms, and growing numbers of new medical tests.

Managing biomedical uncertainty: the technoscientific illness identity

This paper analyses how the biomedical uncertainty of breast cancer contributes to the development of a new type of illness identity that is grounded in biomedical knowledge, advanced technology, and biomedical health and risk surveillance. The technoscientific identity (TSI) develops through the application of sciences and technologies to one's sense of self. Analysing narrative data from 60 in-depth interviews with women diagnosed with breast cancer, this research demonstrates how women diagnosed with breast cancer develop and maintain TSIs through four processes: (1) immersion in professional biomedical knowledge, (2) locating themselves within a technoscientific framework, (3) receiving support for the emerging TSI from the medical system and support networks, and (4) eventually prioritising their biomedical classifications over their suffering. Developing a TSI enables people to make sense of biomedical information, make decisions, and manage medical processes and relationships in the face of biomedical and personal uncertainty even as it extends the reach of technoscience and biomedicalisation.

Variability in interpretive performance at screening mammography and radiologists' characteristics associated with accuracy

PURPOSE

To identify radiologists' characteristics associated with interpretive performance in screening mammography.

MATERIALS AND METHODS

The study was approved by institutional review boards of University of Washington (Seattle, Wash) and institutions at seven Breast Cancer Surveillance Consortium sites, informed consent was obtained, and procedures were HIPAA compliant. Radiologists who interpreted mammograms in seven U.S. regions completed a self-administered mailed survey; information on demographics, practice type, and experience in and perceptions of general radiology and breast imaging was collected. Survey data were linked to data on screening mammograms the radiologists interpreted between January 1, 1998, and December 31, 2005, and included patient risk factors, Breast Imaging Reporting and Data System assessment, and follow-up breast cancer data. The survey was returned by 71% (257 of 364) of radiologists; in 56% (205 of 364) of the eligible radiologists, complete data on screening mammograms during the study period were provided; these data were used in the final analysis. An evaluation of whether the radiologists' characteristics were associated with recall rate, false-positive rate, sensitivity, or positive predictive value of recall (PPV(1)) of the screening examinations was performed with logistic regression models that were adjusted for patients' characteristics and radiologist-specific random effects.

RESULTS

Study radiologists interpreted 1 036 155 screening mammograms; 4961 breast cancers were detected. Median percentages and interquartile ranges, respectively, were as follows: recall rate, 9.3% and 6.3%-13.2%; false-positive rate, 8.9% and 5.9%-12.8%; sensitivity, 83.8% and 74.5%-92.3%; and PPV(1), 4.0% and 2.6%-5.9%. Wide variability in sensitivity was noted, even among radiologists with similar false-positive rates. In adjusted regression models, female radiologists or fellowship-trained radiologists had significantly higher recall and false-positive rates (P < .05, all). Fellowship training in breast imaging was the only characteristic significantly associated with improved sensitivity (odds ratio, 2.32; 95% confidence interval: 1.42, 3.80; P < .001) and the overall accuracy parameter (odds ratio, 1.61; 95% confidence interval: 1.05, 2.45; P = .028).

CONCLUSION

Fellowship training in breast imaging may lead to improved cancer detection, but it is associated with higher false-positive rates.

Screening and prevention of breast cancer in primary care

Mammography remains the mainstay of breast cancer screening. There is little controversy that mammography reduces the risk of dying from breast cancer by about 23% among women between the ages of 50 and 69 years, although the harms associated with false-positive results and overdiagnosis limit the net benefit of mammography. Women in their 70s may have a small benefit from screening mammography, but overdiagnosis increases in this age group as do competing causes of death. While new data support a 16% reduction in breast cancer mortality for 40- to 49-year-old women after 10 years of screening, the net benefit is less compelling in part because of the lower incidence of breast cancer in this age group and because mammography is less sensitive and specific in women younger than 50 years. Digital mammography is more sensitive than film mammography in young women with similar specificity, but no improvements in breast cancer outcomes have been demonstrated. Magnetic resonance imaging may benefit the highest risk women. Randomized trials suggest that self-breast examination does more harm than good. Primary prevention with currently approved medications will have a negligible effect on breast cancer incidence. Public health efforts aimed at increasing mammography screening rates, promoting regular exercise in all women, maintaining a healthy weight, limiting alcohol intake, and limiting postmenopausal hormone therapy may help to continue the recent trend of lower breast cancer incidence and mortality among American women.

Effectiveness of early detection on breast cancer mortality reduction in Catalonia (Spain)

Background

At present, it is complicated to use screening trials to determine the optimal age intervals and periodicities of breast cancer early detection. Mathematical models are an alternative that has been widely used. The aim of this study was to estimate the effect of different breast cancer early detection strategies in Catalonia (Spain), in terms of breast cancer mortality reduction (MR) and years of life gained (YLG), using the stochastic models developed by Lee and Zelen (LZ).

Methods

We used the LZ model to estimate the cumulative probability of death for a cohort exposed to different screening strategies after T years of follow-up. We also obtained the cumulative probability of death for a cohort with no screening. These probabilities were used to estimate the possible breast cancer MR and YLG by age, period and cohort of birth. The inputs of the model were: incidence of, mortality from and survival after breast cancer, mortality from other causes, distribution of breast cancer stages at diagnosis and sensitivity of mammography. The outputs were relative breast cancer MR and YLG.

Results

Relative breast cancer MR varied from 20% for biennial exams in the 50 to 69 age interval to 30% for annual exams in the 40 to 74 age interval. When strategies differ in periodicity but not in the age interval of exams, biennial screening achieved almost 80% of the annual screening MR. In contrast to MR, the effect on YLG of extending screening from 69 to 74 years of age was smaller than the effect of extending the screening from 50 to 45 or 40 years.

Conclusion

In this study we have obtained a measure of the effect of breast cancer screening in terms of mortality and years of life gained. The Lee and Zelen mathematical models have been very useful for assessing the impact of different modalities of early detection on MR and YLG in Catalonia (Spain).

Development of a clinical decision model for thyroid nodules

Background

Thyroid nodules represent a common problem brought to medical attention. Four to seven percent of the United States adult population (10–18 million people) has a palpable thyroid nodule, however the majority (>95%) of thyroid nodules are benign. While, fine needle aspiration remains the most cost effective and accurate diagnostic tool for thyroid nodules in current practice, over 20% of patients undergoing FNA of a thyroid nodule have indeterminate cytology (follicular neoplasm) with associated malignancy risk prevalence of 20–30%. These patients require thyroid lobectomy/isthmusectomy purely for the purpose of attaining a definitive diagnosis. Given that the majority (70–80%) of these patients have benign surgical pathology, thyroidectomy in these patients is conducted principally with diagnostic intent. Clinical models predictive of malignancy risk are needed to support treatment decisions in patients with thyroid nodules in order to reduce morbidity associated with unnecessary diagnostic surgery.

Methods

Data were analyzed from a completed prospective cohort trial conducted over a 4-year period involving 216 patients with thyroid nodules undergoing ultrasound (US), electrical impedance scanning (EIS) and fine needle aspiration cytology (FNA) prior to thyroidectomy. A Bayesian model was designed to predict malignancy in thyroid nodules based on multivariate dependence relationships between independent covariates. Ten-fold cross-validation was performed to estimate classifier error wherein the data set was randomized into ten separate and unique train and test sets consisting of a training set (90% of records) and a test set (10% of records). A receiver-operating-characteristics (ROC) curve of these predictions and area under the curve (AUC) were calculated to determine model robustness for predicting malignancy in thyroid nodules.

Results

Thyroid nodule size, FNA cytology, US and EIS characteristics were highly predictive of malignancy. Cross validation of the model created with Bayesian Network Analysis effectively predicted malignancy [AUC = 0.88 (95%CI: 0.82–0.94)] in thyroid nodules. The positive and negative predictive values of the model are 83% (95%CI: 76%–91%) and 79% (95%CI: 72%–86%), respectively.

Conclusion

An integrated predictive decision model using Bayesian inference incorporating readily obtainable thyroid nodule measures is clinically relevant, as it effectively predicts malignancy in thyroid nodules. This model warrants further validation testing in prospective clinical trials.

Overuse of mammography during the first round of an organized breast cancer screening programme

OBJECTIVES

We examined the frequency of mammography screening among women who had had a screening mammogram recently and therefore generally did not need to repeat the examination.

METHODS

A population-based sample of 50- to 69-year-old women were surveyed immediately before and 8 months after they received an invitation to participate in the first round of screening of the newly organized mammography screening programme in Geneva, Switzerland. These women also received a booklet that included the recommendation to have screening mammograms at 2-year intervals.

RESULTS

The baseline survey identified 660 women who had had a mammogram within the previous 12 months. Of these, 23.2% [95% confidence interval (CI), 20.0-26.6] had an opportunistic mammogram and 4.1% (95% CI, 2.7-5.9) had an organized mammogram during follow-up. Women who had had their last mammogram 6-12 months prior to baseline (vs. more recently), intended to have a mammogram within the next 6 months, wished to receive more information on mammography screening, and had a history of surgical breast biopsy were more likely to have an unnecessary screening mammogram (either organized or opportunistic) during follow-up. Compared with women who had an opportunistic mammogram, women who had an organized mammogram were more likely to be of lower socioeconomic status, to have made their own screening decision and to have anticipated the date of their next mammogram by no more than a few months.

CONCLUSIONS

Opportunistic mammography screening in excess of recommendation is common, and persists despite explicit advice about recommended screening frequency.

Do the results of the process indicators in the Norwegian Breast Cancer Screening Program predict future mortality reduction from breast cancer?

Continuous emphases of quality control are required to achieve reduction in mortality from breast cancer as a consequence of breast cancer screening. Results of the process indicators in the first 6 years in 4 counties in the Norwegian Breast Cancer Screening Program are evaluated and will be presented. Data from women who had their initial (n = 173402) and subsequent (n = 220 058) screening provide the basis for the analysis. The breast cancer detection ratio was 3.2 the expected incidence (based on the incidence before the screening started, 1991-1995) among the initially screened women, decreasing to 2.3 among the subsequently screened. The ratio of interval cancer among the initially screened was 0.25 and 0.72 of the expected incidence, 0-12 and 13-23 months after screening, respectively. For those subsequently screened the proportions were 0.22 and 0.64, respectively. More than 50% of the invasive tumors were less than 15 mm in size, and more than 75% were lymph node negative, among both the initially and subsequently screened. The process indicators achieved in the NBCSP are promising as regards future mortality reduction. The incidence of interval cancer 13-24 months after screening is higher than recommended in the European guidelines.

False-positive mammography and depressed mood in a screening population: findings from the New Hampshire Mammography Network

BACKGROUND

False positives occur in approximately 11% of screening mammographies in the USA and may be associated with psychologic sequelae.

METHODS

We sought to examine the association of false-positive mammography with depressed mood among women in a screening population. Using data from a state-based mammography registry, women who completed a standardized questionnaire between 7 May 2001 and 2 June 2003, a follow-up questionnaire between 19 June 2003 and 8 October 2004 and who received at least one screening mammogram during this interval were identified. False positives were examined in relation to depressed mood.

RESULTS

Eligibility criteria were met by 13 491 women with a median age of 63.9 (SD = 9.6). In the study population, 2107 (15.62%) experienced at least one false positive mammogram and 450 (3.34%) met criteria for depressed mood. Depressed mood was not significantly associated with false positives in the overall population [OR = 0.96; 95% confidence interval (CI) = 0.72-1.28], but this association was seen among Non-White women (OR = 3.23; 95% CI = 1.32-7.91).

CONCLUSION

Depressed mood may differentially affect some populations as a harm associated with screening mammography.

[Screening from an epidemiologic perspective]

The concept of screening is that detection of early disease may permit treatment at a more tractable stage and thus improve prospects for survival and prevention of death from the disease. The principle is so suggestive that the issue of screening appears focused on the determination of appropriate imaging tools or biomarkers and translating them into the health care system as rapidly as possible. However, the application of tests to identify precursors or early signs of disease in a largely unaffected population raises problems which have to be well understood to offer effective high-level screening. The present article provides an overview of the basic obstacles and how to cope with them. It turns out that quality assurance of service screening has to be considered not as optional but as a condition sine qua non.

Implementation of digital mammography in a population-based breast cancer screening program: effect of screening round on recall rate and cancer detection

PURPOSE

To compare the effect of the introduction of digital mammography on the recall rate, detection rate, false-positive rate, and rates of invasive procedures performed in the first and successive rounds of a population-based breast cancer screening program with double reading in Barcelona, Spain.

MATERIALS AND METHODS

The study was approved by the ethics committee; informed consent was not required. Data were compared from 12,958 women aged 50-69 years old who participated in a screening round before the introduction of digital mammography (screen-film mammography group) with data from 6074 women who participated in another screening round after the introduction of digital mammography (digital mammography group). Groups were compared for recall rate and detection rate stratified according to first or successive screening rounds, and logistic regression analysis was performed.

RESULTS

Overall recall rates for screen-film and digital mammography groups were 5.5% and 4.2%, respectively (P < .001). The recall rate was higher in the first screening round (11.5% and 11.1% in the screen-film mammography and digital mammography groups, respectively; P = .68) than in successive screening rounds (3.6% and 2.4% in the screen-film mammography and digital mammography groups, respectively; P < .001). The main factors related to the risk of recall were screen-film mammography group (odds ratio = 1.28), first screening round (odds ratio = 3.53), menopausal status (odds ratio = 0.62), and history of personal benign breast disease (odds ratio = 2.26). No significant differences were found in the cancer detection rate between groups. In the first screening round, this rate was higher in the digital than in the screen-film mammography group (1.1% and 0.4%, respectively; P = .009). The invasive test rate was 2.6% and 1.3% in the screen-film and digital mammography groups, respectively (P < .001) and was lower with digital mammography than with screen-film mammography in both the first and successive screening rounds.

CONCLUSION

Digital mammography may reduce the adverse effects of screening programs if this technique is confirmed to have the same diagnostic accuracy as screen-film mammography.

Cumulative incidence of false-positive results in repeated, multimodal cancer screening

PURPOSE

Multiple cancer screening tests have been advocated for the general population; however, clinicians and patients are not always well-informed of screening burdens. We sought to determine the cumulative risk of a false-positive screening result and the resulting risk of a diagnostic procedure for an individual participating in a multimodal cancer screening program.

METHODS

Data were analyzed from the intervention arm of the ongoing Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, a randomized controlled trial to determine the effects of prostate, lung, colorectal, and ovarian cancer screening on disease-specific mortality. The 68,436 participants, aged 55 to 74 years, were randomized to screening or usual care. Women received serial serum tests to detect cancer antigen 125 (CA-125), transvaginal sonograms, posteroanterior-view chest radiographs, and flexible sigmoidoscopies. Men received serial chest radiographs, flexible sigmoidoscopies, digital rectal examinations, and serum prostate-specific antigen tests. Fourteen screening examinations for each sex were possible during the 3-year screening period.

RESULTS

After 14 tests, the cumulative risk of having at least 1 false-positive screening test is 60.4% (95% CI, 59.8%-61.0%) for men, and 48.8% (95% CI, 48.1%-49.4%) for women. The cumulative risk after 14 tests of undergoing an invasive diagnostic procedure prompted by a false-positive test is 28.5% (CI, 27.8%-29.3%) for men and 22.1% (95% CI, 21.4%-22.7%) for women.

CONCLUSIONS

For an individual in a multimodal cancer screening trial, the risk of a false-positive finding is about 50% or greater by the 14th test. Physicians should educate patients about the likelihood of false positives and resulting diagnostic interventions when counseling about cancer screening.

Near-infrared spectral imaging of the female breast for quantitative oximetry in optical mammography

We present a hybrid continuous-wave, frequency-domain instrument for near-infrared spectral imaging of the female breast based on a tandem, planar scanning of one illumination optical fiber and one collection optical fiber configured in a transmission geometry. The spatial sampling rate of 25 points/cm(2) is increased to 400 points/cm(2) by postprocessing the data with a 2D cubic spline interpolation. We then apply a previously developed spatial second-derivative algorithm to an edge-corrected intensity image (N-image) to enhance the visibility and resolution of optical inhomogeneities in breast tissue such as blood vessels and tumors. The spectral data at each image pixel consist of 515-point spectra over the 650-900 nm wavelength range, thus featuring a spectral density of two data points per nanometer. We process the measured spectra with a paired-wavelength spectral analysis method to quantify the oxygen saturation of detected optical inhomogeneities, under the assumption that they feature a locally higher hemoglobin concentration. Our initial measurements on two healthy human subjects have generated high-resolution optical mammograms displaying a network of blood vessels with values of hemoglobin saturation typically falling within the 60%-95% range, which is physiologically reasonable. This approach to spectral imaging and oximetry of the breast has the potential to efficiently exploit the high intrinsic contrast provided by hemoglobin in breast tissue and to contribute a useful tool in the detection, diagnosis, and monitoring of breast pathologies.

Joint modeling of sensitivity and specificity

Sensitivity and specificity are two customary performance measures associated with medical diagnostic tests. Typically, they are modeled independently as a function of risk factors using logistic regression, which provides estimated functions for these probabilities. Change in these probabilities across levels of risk factors is of primary interest and the indirect relationship is often displayed using a receiver operating characteristic curve. We refer to this as analysis of 'first-order' behavior. Here, we consider what we refer to as 'second-order' behavior where we examine the stochastic dependence between the (random) estimates of sensitivity and specificity. To do so, we argue that a model for the four cell probabilities that determine the joint distribution of screening test result and outcome result is needed. Such a modeling induces sensitivity and specificity as functions of these cell probabilities. In turn, this raises the issue of a coherent specification for these cell probabilities, given risk factors, i.e. a specification that ensures that all probabilities calculated under it fall between 0 and 1. This leads to the question of how to provide models that are coherent and mechanistically appropriate as well as computationally feasible to fit, particularly with large data sets. The goal of this article is to illuminate these issues both algebraically and through analysis of a real data set.

New diagnostic techniques for breast cancer detection

Breast imaging has made huge advances in the last decade, and along with newer techniques to diagnose primary breast cancer, many novel methods are being used and look promising in detecting distant metastasis, recurrent disease and assessing response to treatment. Full-field digital mammography optimizes the lesion–background contrast and gives better sensitivity, and it is possible to see through the dense tissues by altering computer windows; this may be particularly useful in younger women with dense breasts. The need for repeat imaging is reduced, with the added advantage of reduced radiation dose to patients. Computer-aided detection systems may help the radiologist in interpretation of both conventional and digital mammograms. MRI has a role in screening women at high risk for breast cancer. It also aids in cancer management by assessing response to treatment and can help in deciding appropriate surgery by providing accurate information on the extent of the tumor. Newer diagnostic techniques such as sestamibi scans, optical imaging and molecular diagnostic techniques look promising, but need more investigation into their use. Their roles will appear clearer in coming years, and they may prove to be of help in further investigating lesions that are indeterminate on standard imaging. Other upcoming techniques are contrast-enhanced mammography and tomosynthesis. These may give additional information in indeterminate lesions, and when used in screening they aid in reducing recall rates, as shown in recent studies. PET/computed tomography has a role in detecting local disease recurrence and distant metastasis in breast cancer patients.

Noninvasive imaging of bioimpedance distribution by means of current reconstruction magnetic resonance electrical impedance tomography

We have developed a novel magnetic resonance electrical impedance tomography (MREIT) algorithm-current reconstruction MREIT algorithm-for noninvasive imaging of electrical impedance distribution of a biological system using only one component of magnetic flux density. The newly proposed algorithm uses the inverse of Biot-Savart Law to reconstruct the current density distribution, and then, uses a modified J-substitution algorithm to reconstruct the conductivity image. A series of computer simulations has been conducted to evaluate the performance of the proposed current reconstruction MREIT algorithm with simulation settings for breast cancer imaging applications, with consideration of measurement noise, current injection strength, size of simulated tumors, spatial resolution, and position dependency. The present simulation results are highly promising, demonstrating the high spatial resolution, high accuracy in conductivity reconstruction, and robustness against noise of the proposed algorithm for imaging electrical impedance of a biological system. The present MREIT method may have potential applications to breast cancer imaging and imaging of other organs.

Quality of life valuations of mammography screening

OBJECTIVE

To obtain quality-of-life (QOL) valuations associated with mammography screening and breast cancer treatment that are suitable for use in cost-effectiveness analyses.

METHODS

Subjects comprised 131 women (age range 50-79 years) randomly sampled from a breast cancer screening program. In an in-person or telephone interview, women rated the QOL impact of 14 clinical scenarios (ranging from mammography to end-of-life care for breast cancer) using a visual analogue scale anchored by death (0) and perfect health/quality of life (100).

RESULTS

Women rated the scenarios describing true negative results, false positive results, and routine screening mammography at 80 or above on a scale of 0-100, suggesting that they perceive these states as being close to perfect health. They rated adjuvant chemotherapy (39.7; range 10-90), palliation/end-of-life care (35.8; range 0-100), and recurrence at 1 year (33.0; range 0-95) the lowest, suggesting that these health states are perceived as compromised. Women rated receiving news of a breast cancer diagnosis (true positive) (45.7; range 5-100) and receiving delayed news of a breast cancer diagnosis (false negative) (48.5; range 5-100) as being comparable to undergoing mastectomy (48.3; range 10-100) and radiation therapy (46.2; range 5-100) for breast cancer.

CONCLUSIONS

These data can be used to update cost analyses of mammography screening that wish to take into account the QOL impact of screening.

Medical directors of breast imaging centers: beyond films

Over the past decade, breast radiologists have been increasingly asked to fulfill a new dynamic role as medical directors of breast imaging centers. To our knowledge, there are no standardized job descriptions nor defined roles and responsibilities for this position. Job descriptions are usually crafted to fit unique institutional and individual situations. To be an effective medical director of a breast imaging center, breast imagers must be more than just film readers. In this article, the authors describe the diverse roles of contemporary medical directors of breast imaging centers.

Initiation of benzodiazepines in the elderly after hospitalization

OBJECTIVE

To estimate the rate of new chronic benzodiazepine use after hospitalization in older adults not previously prescribed with benzodiazepines.

DESIGN

Retrospective cohort study using linked, population-based administrative data.

SETTING

Ontario, Canada between April 1, 1992 and March 31, 2005.

PARTICIPANTS

Community-dwelling seniors who had not been prescribed benzodiazepine drugs in the year before hospitalization were selected from all 1.4 million Ontario residents aged 66 years and older.

MAIN OUTCOME MEASURES

New chronic benzodiazepine users, defined as initiation of benzodiazepines within 7 days after hospital discharge and an additional claim within 8 days to 6 months. We used multivariate logistic regression to examine for the effect of hospitalization on the primary outcome after adjusting for confounders.

RESULTS

There were 405,128 patient hospitalizations included in the cohort. Benzodiazepines were prescribed to 12,484 (3.1%) patients within 7 days of being discharged from hospital. A total of 6,136 (1.5%) patients were identified as new chronic benzodiazepine users. The rate of new chronic benzodiazepine users decreased over the study period from 1.8% in the first year to 1.2% in the final year (P < .001). Multivariate logistic regression found that women, patients admitted to the intensive care unit or nonsurgical wards, those with longer hospital stays, higher overall comorbidity, a prior diagnosis of alcoholism, and those prescribed more medications had significantly elevated adjusted odds ratios for new chronic benzodiazepine users. Older individuals had a lower risk for the primary outcome.

CONCLUSION

New benzodiazepine prescription after hospitalization occurs frequently in older adults and may result in chronic use. A systemic effort to address this risky practice should be considered.

[The role of epidemiological quality parameters in a mammography screening programme]

In the recently established mammography screening programme, for the first time in Germany an extensive data collection for prompt quantification of specified quality parameters will be intrinsic to an early detection programme. Epidemiological parameters taken from the European Guidelines are central. This article outlines how epidemiology is involved in quality assurance of cancer screening and why epidemiological quality indicators will be quantified. The reasons for focussing on those parameters, on which the European Guidelines and now the German programme are based, and their significance in the long-term effectiveness of this programme are explained.

Cumulative false positive recall rate and association with participant related factors in a population based breast cancer screening programme

STUDY OBJECTIVE

To investigate the cumulative false positive recall rate throughout the period of participation in a population based breast cancer screening programme and to examine its association with women related factors.

DESIGN

Analysis of a database to estimate the cumulative false positive recall rate after 10 biennial mammograms in a cohort of women. Cumulative risk after 10 rounds was calculated by projecting forward the information available on the four rounds. Logistic regression was used to evaluate the association between the cumulative risk of false positive recall and women related factors.

SETTING

Population based breast cancer screening programme in Barcelona City (Spain).

PARTICIPANTS

8502 women aged 50-69 years who participated in four consecutive screening rounds. Eligible women had received a mammogram in the first screening round between 1 December 1995 and 31 December 1996.

MAIN RESULTS

The false positive recall rate in the first screening for women who entered the screening programme at the age of 50-51 years was assessed at 10.6% (95% CI 8.9, 12.3). In the second screening this risk decreased to 3.8% (95% CI 2.7, 4.9) and remained almost constant in subsequent rounds. After 10 mammograms, the cumulative false positive recall rate was estimated at 32.4% (95% CI 29.7, 35.1). The factors associated with a higher cumulative risk of false positive recall were: previous benign breast disease (OR = 8.48; CI 7.39, 9.73), perimenopausal status (OR = 1.62; CI 1.12, 2.34), body mass index above 27.3 (OR = 1.17; CI 1.02, 1.34), and age 50-54 years (OR = 1.15; CI 1.00, 1.31).

CONCLUSIONS

One third of women could have at least one false positive recall over 10 biennial screens. Women participating in screening programmes should be informed about this risk, especially those with associated factors.

Development and validation of queries using structured query language (SQL) to determine the utilization of comparison imaging in radiology reports stored on PACS

The purpose of this research was to develop queries that quantify the utilization of comparison imaging in free-text radiology reports. The queries searched for common phrases that indicate whether comparison imaging was utilized, not available, or not mentioned. The queries were iteratively refined and tested on random samples of 100 reports with human review as a reference standard until the precision and recall of the queries did not improve significantly between iterations. Then, query accuracy was assessed on a new random sample of 200 reports. Overall accuracy of the queries was 95.6%. The queries were then applied to a database of 1.8 million reports. Comparisons were made to prior images in 38.69% of the reports (693,955/1,793,754), were unavailable in 18.79% (337,028/1,793,754), and were not mentioned in 42.52% (762,771/1,793,754). The results show that queries of text reports can achieve greater than 95% accuracy in determining the utilization of prior images.

Long-term risk of false-positive screening results and subsequent biopsy as a function of mammography use

PURPOSE

To retrospectively determine the long-term risk of false-positive mammographic assessments and to evaluate the effect of screening regularity on the risk of false-positive events.

MATERIALS AND METHODS

Institutional review board approval was obtained, and informed consent was waived. Retrospective analysis was performed for the occurrence of false-positive assessments among 83,511 women who underwent 314,185 mammographic examinations from January 1, 1985, to February 19, 2002. Data were collected from a database that had been assembled prospectively. Two categories of false-positive events were examined: biopsies that did not reveal cancer and false-positive mammographic assessments. Rates of false-positive events were compared by using a chi2 analysis, and 95% confidence limits were calculated. Because comparisons of multiple pairs were considered, all P values that demonstrated statistical significance exceeded the requirement of the Bonferroni correction.

RESULTS

While the overall rates of biopsies that did not reveal cancer and of false-positive mammographic assessments were similar to those found in other studies, most of the burden of false-positive events was borne by women who underwent intermittent screening. Long-term rates of false-positive events were lower among women who underwent regular screening than among those who underwent intermittent screening. In the 5-year group, 2.9% of women who underwent five mammographic examinations over the next 5 years had biopsy results that did not reveal cancer, whereas 4.6% of women who underwent three mammographic examinations over the next 5 years had biopsy results that did not reveal cancer. For women who underwent regular screening, the risk of undergoing biopsies that did not reveal cancer declined over time to 0.25% per year after several years of screening, a value that is lower than the risk of these events among women who did not undergo screening. The rate of false-positive mammographic assessments was also lower for women who underwent regular screening than for those who underwent intermittent screening.

CONCLUSION

Prompt annual attendance for mammographic screening reduces the occurrence of false-positive mammographic results.

Determinants of false positive recall in an Australian mammographic screening program

We conducted a case-control study (n=30128) to assess the importance of clinical (e.g., family history, age, hormone replacement therapy (HRT) use and duration) and service-related characteristics (e.g., time since introduction of Kodak MINR2000 film, year of screen) for false positive (FP) recall at BreastScreen Victoria, Australia. There was an age-adjusted upward trend in FP recall rates with year of screen at first (odds ratio (OR) 1.11, 95% confidence interval (95% CI) 1.08-1.13) and subsequent rounds (OR 1.04, 95% CI 1.01-1.06). In the multivariate analysis, the upward trend only remained for first round and age and family history also remained statistically significant at first round. At subsequent rounds the time since introduction of MINR2000, age, strong family history of breast cancer, use of HRT, recall at previous screen and previous screen at more than 27 months were all important predictors of FP recall. The rise in FP rates with year of screen at first round screening is of concern and may require further training of radiologists to improve confidence when viewing films when there a no films for comparison.

Variation in false-positive rates of mammography reading among 1067 radiologists: a population-based assessment

BACKGROUND

The accuracy of mammography reading varies among radiologists. We conducted a population-based assessment on radiologist variation in false- positive rates of screening mammography and its associated radiologist characteristics.

METHODS

About 27,394 screening mammograms interpreted by 1067 radiologists were identified from a 5% non-cancer sample of Medicare claims during 1998-1999. The data were linked to the American Medical Association Masterfile to obtain radiologist characteristics. Multilevel logistic regression models were used to examine the radiologist variation in false-positive rates of screening mammography and the associated radiologist characteristics.

RESULTS

Radiologists varied substantially in the false-positive rates of screening mammography (ranging from 1.5 to 24.1%, adjusting for patient characteristics). A longer time period since graduation is associated with lower false-positive rates (odds ratio [OR] for every 10 years increase: 0.87, 95% Confidence Interval [CI], 0.81-0.94) and female radiologists had higher false-positive rates than male radiologists (OR = 1.25, 95% CI, 1.05-1.49), adjusting for patient and other radiologist characteristics. The unmeasured factors contributed to about 90% of the between-radiologist variance.

CONCLUSIONS

Radiologists varied greatly in accuracy of mammography reading. Female and more recently trained radiologists had higher false-positive rates. The variation among radiologists was largely due to unmeasured factors, especially unmeasured radiologist factors. If our results are confirmed in further studies, they suggest that system-level interventions would be required to reduce variation in mammography interpretation.

Examining accuracy of screening mammography using an event order model

Screening mammography is a widely used method for breast cancer detection. For each mammogram we propose a performance model based on order of outcomes. That is, we envision an initial assessment, a follow up assessment if the initial one is positive and, eventually, a determination of whether cancer was present or not. A model can be built at each stage reflecting effects due to patient characteristics, to the facility where mammogram was performed and to the radiologist reading the mammogram. Since assessment is not perfectly associated with outcome, familiar rates of agreement and disagreement are of interest. These rates can be investigated at various levels of risk factors of interest. The approach is illustrated with screening mammography data from the Group Health Cooperative in Seattle, WA. A Bayesian framework is adopted for inference and an analysis of the data set is presented.

Informed consent for mammography screening: modelling the risks and benefits for American women

INTRODUCTION

In order to facilitate informed decision making, women require information on the probabilities of different outcomes with mammography screening. This paper derives these probabilities for a US population and illustrates them visually in a readily understandable format.

METHODS

Probabilities of the breast cancer mortality, all cause mortality and further investigation are derived from published data on mortality from breast cancer and published estimates of effectiveness using a life-table method. Probabilities are calculated of surviving to age 75 from age 40 with and without two-yearly mammography screening from age 40 and age 50. Probabilities are also calculated that a woman will be referred for further assessment or biopsy or die from breast cancer despite screening. To avoid being misled, these outcomes are presented in the form of a single decision aid illustrating the outcomes for 1000 women choosing each alternative: mammography screening or no mammography screening.

RESULTS

Of 1000 women undergoing two-yearly mammography screening from age 40 an additional four (3.7 per 1000) will reach the age of 75; of the survivors 514 will be referred for further investigation and 138 will undergo biopsy. Of 1000 women screened from age 50 an additional three (3.3 per 1000) will reach age 75; of the survivors 408 will be referred for further investigation and 94 will undergo biopsy. Mammography from age 40 to 49 reduces mortality by 0.4 in 1000. This information is readily presented visually.

CONCLUSIONS

It is possible to provide realistic estimates of the effects of mammography screening on mortality in a readily understandable format. Women require this information if they are to make informed choices about mammography screening.

Organized breast screening programs in Canada: effect of radiologist reading volumes on outcomes

PURPOSE

To examine retrospectively the relationship between radiologist screening program reading volumes and interpretation results.

MATERIALS AND METHODS

This research project was reviewed by the University of British Columbia Research Ethics Board. Informed patient consent was not required. Data were requested from Canadian provincial screening programs for the period 1988-2000. Cancer detection rates, abnormal interpretation rates, and positive predictive values (PPVs) were calculated for individual radiologists in those programs. Multivariate Poisson mixed regression models were used to examine the effect of patient age, screening examination sequence (first or subsequent screening examination), province, radiologist reading volume, and interradiologist differences on cancer detection rate, abnormal interpretation rate, and PPV.

RESULTS

The results of the interpretation of 1406678 screening mammograms by 304 radiologists from seven provincial programs were analyzed. Cancer detection rate, abnormal interpretation rate, and PPV all varied according to age of woman screened and screening sequence and across the sample of radiologists. None of the rates varied by province. Neither the cancer detection rate nor the abnormal interpretation rate varied by reading volume, but the average PPV was increased by 34% for volumes over 2000 mammograms versus volumes of 480-699 mammograms per year. There was no evidence that the magnitude of variability around the average, for radiologists reading the same volume of mammograms, varied across different volume groups for any of the outcome measures.

CONCLUSION

Cancer detection did not vary with reading volume. The average PPV for individual radiologists increased as reading volume rose up to 2000 mammograms per year; it stabilized at higher volumes.

Hormone replacement therapy and false positive recall in the Million Women Study: patterns of use, hormonal constituents and consistency of effect

INTRODUCTION

Current and recent users of hormone replacement therapy (HRT) have an increased risk of being recalled to assessment at mammography without breast cancer being diagnosed ('false positive recall'), but there is limited information on the effects of different patterns of HRT use on this. The aim of this study is to investigate in detail the relationship between patterns of use of HRT and false positive recall.

METHODS

A total of 87,967 postmenopausal women aged 50 to 64 years attending routine breast cancer screening at 10 UK National Health Service Breast Screening Units from 1996 to 1998 joined the Million Women Study by completing a questionnaire before screening and were followed for their screening outcome.

RESULTS

Overall, 399 (0.5%) participants were diagnosed with breast cancer and 2,629 (3.0%) had false positive recall. Compared to never users of HRT, the adjusted relative risk (95% CI) of false positive recall was: 1.62 (1.43-1.83), 1.80 (1.62-2.01) and 0.76 (0.52-1.10) in current users of oestrogen-only HRT, oestrogen-progestagen HRT and tibolone, respectively (p (heterogeneity) < 0.0001); 1.65 (1.43-1.91), 1.49 (1.22-1.81) and 2.11 (1.45-3.07) for current HRT used orally, transdermally or via an implant, respectively (p (heterogeneity) = 0.2); and 1.84 (1.67-2.04) and 1.75 (1.49-2.06) for sequential and continuous oestrogen-progestagen HRT, respectively (p (heterogeneity) = 0.6). The relative risk of false positive recall among current users appeared to increase with increasing time since menopause, but did not vary significantly according to any other factors examined, including duration of use, hormonal constituents, dose, whether single- or two-view screening was used, or the woman's personal characteristics.

CONCLUSION

Current use of oestrogen-only and oestrogen-progestagen HRT, but not tibolone, increases the risk of false positive recall at screening.

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.

Imaging and Cancer: Research Strategy of the American College of Radiology Imaging Network

The American College of Radiology Imaging Network (ACRIN) is a cooperative group funded by the National Cancer Institute and dedicated to developing and conducting clinical trials of diagnostic imaging and image-guided treatment technologies. ACRIN's six disease site committees are responsible for developing scientific strategies and resultant trials within the framework of ACRIN's five key hypotheses: (a) Screening and early detection with imaging can reduce cancer-specific mortality. (b) Less invasive image-guided therapeutic methods can reduce the mortality and morbidity associated with treating cancer. (c) Molecular-based physiologic and functional imaging can improve the diagnosis and staging of cancer, thus improving treatment. (d) Functional imaging can portray the effectiveness of treatment earlier and more accurately, thus reducing mortality and improving the likelihood of a cure. (e) Informatics and other "smart systems" can improve the evaluation of patients with cancer, thus leading to better and more effective treatments. This article details ACRIN's research strategy according to disease site through the year 2007.

Issues in breast cancer screening

This paper will review the use of screening mammography in the United States, with an emphasis on its limitations as currently practiced. It will then emphasize several areas where breast cancer imaging practice can be improved, namely in reducing overtreatment of potentially nonlethal cancers, in monitoring the effectiveness of nonsurgical therapies, and in guiding noninvasive therapies. Any new modality that is to have an impact on breast cancer mortality must perform comparably to screening mammography to become widely utilized. While mammography is not perfect, it has set a high threshold that other modalities must reach before they will be widely utilized for screening or diagnosis.

Breast cancer yield for screening mammographic examinations with recommendation for short-interval follow-up

PURPOSE

To compare cancer yield for screening examinations with recommendation for short-interval follow-up after diagnostic imaging work-up versus after screening mammography only.

MATERIALS AND METHODS

From January 1996 to December 1999, Breast Imaging Reporting and Data System assessments and recommendations were collected prospectively for 1,171,792 screening examinations in 758,015 women aged 40-89 years at seven mammography registries in Breast Cancer Surveillance Consortium. Registries obtained waiver of signed consent or collected signed consent in accordance with institutional review boards at each location. Diagnosis of invasive cancer or ductal carcinoma in situ within 24 months of screening examination and tumor stage and size for invasive cancer were determined through linkage to pathology database or tumor registry. chi2 test was used to determine significant differences between groups.

RESULTS

Overall, 5.2% of first and 1.7% of subsequent screens included recommendation for short-interval follow-up, which was similar to likelihood of recommendation for diagnostic evaluation (first screens, 4.6%; subsequent, 2.6%). Most recommendations for short-interval follow-up were based on screening mammography alone (86.2% of first screens, 77.5% of subsequent). Yield of cancer for screening examinations with probably benign finding (PBF) and recommendation for short-interval follow-up based on screening mammography alone tended to be lower than in those with PBF and recommendation for short-interval follow-up after additional work-up (first screens: 0.54% vs 0.96%, P=.10; subsequent: 1.50% vs 1.73%, P=.26). Proportion of stage II and higher disease tended to be higher for examinations with PBF and recommendation for short-interval follow-up based on screening mammography alone compared with those recommended for short-interval follow-up after additional work-up (first screens: 34.7% vs 24.4%, P=.43; subsequent: 27.5% vs 19.2%, P=.13).

CONCLUSION

Many first screening examinations include recommendation for short-interval follow-up based on screening mammography alone. Cancer yield for these examinations is low and is lower than that with diagnostic work-up prior to short-interval follow-up recommendation. Absence of diagnostic work-up prior to short-interval follow-up recommendation may result in periodic surveillance of a high proportion of benign lesions.

Resolution and contrast in magnetic resonance electrical impedance tomography (MREIT) and its application to cancer imaging

It has been reported that the electrical impedance of malignancies could be 20-40 times lower than healthy tissues and benign formations. Therefore, in vivo impedance imaging of suspicious lesions may prove to be helpful in improving the sensitivity and specificity of detecting malignant tumors. Several systems have been developed to map the conductivity distribution inside a volume of tissue, however they suffer from poor spatial resolution because the measurements are taken only from surface electrodes. MRI based impedance imaging (MREIT) is a novel method, in which weak electrical currents are injected into the tissue and the resulting perturbations in the magnetic field are measured using MRI. This method has been shown to provide better resolution compared to previous techniques of impedance imaging because the measurements are taken from inside the object on a uniform grid. Thus, it has the potential to be a useful modality that may detect malignancies earlier. Several phantom imaging experiments were performed to investigate the spatial resolution and dynamic range of contrast of this technique. The method was also applied to a live rat bearing a R3230 AC tumor. Tumor location was identified by contrast enhanced imaging.

Reader variability in mammography and its implications for expected utility over the population of readers and cases

The multiple-reader, multiple-case (MRMC) approach to receiver operating characteristic (ROC) analysis is becoming the dominant assessment paradigm in medical imaging. Its most common version involves having many readers read every patient case in the study, a critical feature since differences among competing imaging modalities are often dominated by differences in reader performance. The present authors have carried out MRMC ROC analysis on a uniquely large data set for mammography. The analysis quantifies the great range of observed reader skill in that data set. It also demonstrates that the sample sizes are sufficiently large that the conclusions generalize to the populations sampled here with little uncertainty from the finite sample size. A schematic approach to bracketing the utility matrix is then used to study trends in the resulting expected utility functions that correspond to the range of observed ROC curves. This is done for both the screening and the diagnostic context. The results raise 2 hypotheses for further investigation. First, it is possible that the present ambiguity surrounding the effectiveness of mammography is due in part to the observed range of reader skills and corresponding expected utility functions. Second, it is possible that computer-assisted modalities for mammography may lead to improvements in the expected utility function not only for screening but also in the diagnostic context, especially for the lower performing readers.

Estimating the cumulative risk of a false-positive test in a repeated screening program

The goal of screening tests for a chronic disease such as cancer is early detection and treatment with a consequent reduction in mortality from the disease. Screening tests, however, might produce false positive and false-negative results. With an increasing number of screening tests, it is clear that the risk of a false-positive screen, a finding with potentially significant emotional, financial, and health costs, also increases. Elmore et al. (1998, New England Journal of Medicine 338, 1089-1096), Christiansen et al. (2000, Journal of the National Cancer Institute 92, 1657-1666), and Gelfand and Wang (2000, Statistics in Medicine 19, 1865-1879) investigated this problem under the somewhat unrealistic assumption that the choice of making the decision to drop out at the kth screen does not depend upon the results of the earlier k - 1 screens. In this article we obtain sufficient and necessary conditions for their assumption to hold and use one of them to provide a method for testing the validity of the assumption. A new model which does not depend on their assumption is introduced. The maximum likelihood estimator of the cumulative risk of receiving a false-positive screen under the new model is derived and its asymptotic normality is proved. The extension of the new model by incorporating covariate information is also considered. We apply our testing method and the new model to data from the breast cancer screening trial of the Health Insurance Plan of Greater New York.

The Economic Impact of False-Positive Cancer Screens

Objective: Despite the promotion and widespread use of routine cancer screening, little is known about the economic consequences of false-positive screening results. We evaluated the medical and nonmedical costs associated with false-positive prostate, lung, colorectal, and ovarian cancer screens.

Method: We identified 1,087 Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial participants enrolled in a large managed care organization. Medical care use and costs were compiled from automated sources and trial data. Nonmedical care costs to patients with a false-positive lung cancer screen were obtained by telephone interview (n = 98).

Results: Forty-three percent of the study sample incurred at least one false-positive cancer screen. The majority of these patients (83%) received follow-up care. Prior to and after controlling for participant characteristics, significantly higher medical care expenditures in the year following screening were found among those with a false-positive screen. The adjusted mean difference was $1,024 for women and $1,171 for men. Among lung cancer screening patients, few nonmedical care costs were identified beyond the time (mean, 1.5 hours) spent receiving care.

Conclusion: The results here indicate that false-positive results among some available cancer screening tests are relatively common, that patients incurring a false-positive screen tend to receive follow-up testing, and that such follow-up is not without associated medical costs. Along with trials evaluating the health benefits of available cancer screening modalities, investigations into potential undesirable consequences of cancer screening are also warranted.

Adverse effects of screening mammography

The main risks and other adverse consequences from screening mammography include discomfort from breast compression, patient recall for additional imaging, and false positive biopsies. Although these risks affect a larger number of women than those who benefit from screening, the risks are less consequential than the life-sparing benefits from early detection. Radiation risk, even for multiple screenings, is negligible at current mammography doses. Anxiety before screening or resulting from supplementary imaging work-up, short-term follow-up, cyst aspiration, and biopsy has not dampened the enthusiasm of most women for the value of early detection.