Multicenter comparative multimodality surveillance of women at genetic-familial high risk for breast cancer (HIBCRIT study): interim results

Molecular breast imaging

Molecular breast imaging (MBI) is a new nuclear medicine technique that utilizes small semiconductor-based gamma-cameras in a mammographic configuration to provide high-resolution functional images of the breast. Current studies with MBI have used Tc-99m sestamibi, which is an approved agent for breast imaging. The procedure is relatively simple to perform. Imaging can be performed within 5 min postinjection, with the breast lightly compressed between the two detectors. Images of each breast are acquired in the craniocaudal and mediolateral oblique projections facilitating comparison with mammography. Key studies have confirmed that MBI has a high sensitivity for the detection of small breast lesions. In patients with suspected breast cancer, MBI has an overall sensitivity of 90%, with a sensitivity of 82% for lesions less than 10 mm in size. Sensitivity was lowest for tumors less than 5 mm in size. Tumor detection does not appear to be dependent on tumor type, but rather on tumor size. Studies using MBI and breast-specific gamma-imaging have shown that these methods have comparable sensitivity to breast MRI. A large clinical trial compared MBI with screening mammography in over 1000 women with mammographically dense breast tissue and increased risk of breast cancer and showed that MBI detected two-to three-times more cancers than mammography. In addition, MBI appears to have slightly better specificity than mammography in this trial. MBI provides high-resolution functional images of the breast and its potential applications range from evaluation of the extent of disease to a role as an adjunct screening technique in certain high-risk populations. MBI is highly complementary to existing anatomical techniques, such as mammography, tomosynthesis and ultrasound.

Found in transcription: gene expression and other novel blood biomarkers for the early detection of breast cancer

Early detection of a growing breast tumor is of key importance for patient survival. Despite limitations, mammography screening has improved the detection of breast tumors, however many tumors are not detected. This is especially true for younger women and women with high breast density. Novel diagnostic blood biomarkers either generated by the tumor and released into the blood, or generated by nontumor cells as a response to the tumor presence, can now potentially help improve the accuracy of early-stage breast cancer detection. They include multicomponent biomarkers, circulating tumor cells and RNA expression of peripheral blood. These novel biomarkers and their potential use will be presented and discussed in this review, with special emphasis on gene expression-based markers.

Multimodality screening of high-risk women: a prospective cohort study

PURPOSE

Mammography has been established as the primary imaging screening method for breast cancer; however, the sensitivity of mammography is limited, especially in women with dense breast tissue. Given the limitations of mammography, interest has developed in alternative screening techniques. This interest has led to numerous studies reporting mammographically occult breast cancers detected on magnetic resonance imaging (MRI) or ultrasound. In addition, digital mammography was shown to be more sensitive than film mammography in selected populations. Our goal was to prospectively compare cancer detection of digital mammography (DM), whole-breast ultrasound (WBUS), and contrast-enhanced MRI in a high-risk screening population previously screened negative by film screen mammogram (FSM).

METHODS

During a 2-year period, 609 asymptomatic high-risk women with nonactionable FSM examinations presented for a prospective multimodality screening consisting of DM, WBUS, and MRI. The FSM examinations were reinterpreted by study radiologists. Patients had benign or no suspicious findings on clinical examination. The cancer yield by modality was evaluated.

RESULTS

Twenty cancers were diagnosed in 18 patients (nine ductal carcinomas in situ and 11 invasive breast cancers). The overall cancer yield on a per-patient basis was 3.0% (18 of 609 patients). The cancer yield by modality was 1.0% for FSM (six of 597 women), 1.2% for DM (seven of 569 women), 0.53% for WBUS (three of 567 women), and 2.1% for MRI (12 of 571 women). Of the 20 cancers detected, some were only detected on one imaging modality (FSM, n = 1; DM, n = 3; WBUS, n = 1; and MRI, n = 8).

CONCLUSION

The addition of MRI to mammography in the high-risk group has the greatest potential to detect additional mammographically occult cancers. The incremental cancer yield of WBUS and DM is much less.

Evaluating the correlation between film mammography and MRI for screening women with increased breast cancer risk

RATIONALE AND OBJECTIVES

Breast magnetic resonance imaging (MRI) is increasingly being added to mammography for screening asymptomatic women at increased risk of breast cancer. Because the direction and extent of correlation between mammography and MRI could potentially result in over- or underestimation of the diagnostic gain related to using MRI as an adjunct to mammographic screening, we performed an analysis to evaluate the extent of correlation between mammography and MRI.

MATERIALS AND METHODS

We reviewed the published literature to identify multimodality breast cancer screening studies reporting the sensitivity of mammography and MRI, alone and in combination, for breast cancer diagnosis. After calculating the expected sensitivity of combined mammography and MRI under conditions of test independence (no correlation), we compared the calculated and observed sensitivities for combined mammography and MRI. We then calculated correlation coefficients for mammography and MRI.

RESULTS

Seven studies of multimodality screening in women at increased risk of developing breast cancer were included for analysis. Of these studies, the correlation between film mammography and MRI was positive in three studies, negative in two studies, and not identified in two studies. The calculated correlation coefficients ranged from -0.38 to 0.18. In six of seven studies, the 95% confidence interval for the correlation coefficient included 0.0, indicating no significant correlation.

CONCLUSIONS

Evidence from published trials of multimodality breast cancer screening identified no statistically significant correlation between film mammography and MRI. Using both tests for breast cancer screening is likely to improve the early detection of breast cancer in women at increased risk.

[Breast cancer screening imaging: what do we do]

The purpose of this review is to evaluate the value of different breast imaging technics and their place for individual and mass screening of breast cancer according to the randomized studies on digital mammography and ultrasound screening. Analogic and numerical mammograms are validated for screening of women aged from 50 and 74 years. The additional value of ultrasound is therefore proven when the increased risk is moderate. When risk is higher (genetic or familial), MRI is the method of choice associated with conventional imaging. Individual screening is recommended before 50 for women aged from 45 and 50 and for those over 74 using the same procedures as organized screening.

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.

Temporal sampling requirements for reference region modeling of DCE-MRI data in human breast cancer

PURPOSE

To assess the temporal sampling requirements needed for quantitative analysis of dynamic contrast-enhanced MRI (DCE-MRI) data with a reference region (RR) model in human breast cancer.

MATERIALS AND METHODS

Simulations were used to study errors in pharmacokinetic parameters (K(trans) and v(e)) estimated by the RR model using six DCE-MRI acquisitions over a range of pharmacokinetic parameter values, arterial input functions, and temporal samplings. DCE-MRI data were acquired on 12 breast cancer patients and parameters were estimated using the native resolution data (16.4 seconds) and compared to downsampled 32.8-second and 65.6-second data.

RESULTS

Simulations show that, in the majority of parameter combinations, the RR model results in an error less than 20% in the extracted parameters with temporal sampling as poor as 35.6 seconds. The experimental results show a high correlation between K(trans) and v(e) estimates from data acquired at 16.4-second temporal resolution compared to the downsampled 32.8-second data: the slope of the regression line was 1.025 (95% confidence interval [CI]: 1.021, 1.029), Pearson's correlation r = 0.943 (95% CI: 0.940, 0.945) for K(trans), and 1.023 (95% CI: 1.021. 1.025), r = 0.979 (95% CI: 0.978, 0.980) for v(e). For the 64-second temporal resolution data the results were: 0.890 (95% CI: 0.894, 0.905), r = 0.8645, (95% CI: 0.858, 0.871) for K(trans), and 1.041 (95% CI: 1.039, 1.043), r = 0.970 (95% CI: 0.968, 0.971) for v(e).

CONCLUSION

RR analysis allows for a significant reduction in temporal sampling requirements and this lends itself to analyze DCE-MRI data acquired in practical situations.

Fusion of MRI and sonography image for breast cancer evaluation using real-time virtual sonography with magnetic navigation: first experience

OBJECTIVE

We recently developed a real-time virtual sonography (RVS) system that enables simultaneous display of both sonography and magnetic resonance imaging (MRI) cutaway images of the same site in real time. The aim of this study was to evaluate the role of RVS in the management of enhancing lesions visualized with MRI.

METHODS

Between June 2006 and April 2007, 65 patients underwent MRI for staging of known breast cancer at our hospital. All patients were examined using mammography, sonography, MRI and RVS before surgical resection. Results were correlated with histopathologic findings. MRI was obtained on a 1.5 T imager, with the patient in the supine position using a flexible body surface coil. Detection rate was determined for index tumors and incidental enhancing lesions (IELs), with or without RVS.

RESULTS

Overall sensitivity for detecting index tumors was 85% (55/65) for mammography, 91% (59/65) for sonography, 97% (63/65) for MRI and 98% (64/65) for RVS. Notably, in one instance in which the cancer was not seen on MRI, RVS detected it with the supplementation of sonography. IELs were found in 26% (17/65) of the patients. Of 23 IELs that were detected by MRI, 30% (7/23) of IELs could be identified on repeated sonography alone, but 83% (19/23) of them were identified using the RVS system (P = 0.001). The RVS system was able to correctly project enhanced MRI information onto a body surface, as we checked sonography form images.

CONCLUSIONS

Our results suggest that the RVS system can identify enhancing breast lesions with excellent accuracy.

Breast cancer screening: emerging role of new imaging techniques as adjuncts to mammography

Early detection of breast cancer has been shown to reduce breast cancer deaths in randomised controlled trials (RCTs) of mammography in women aged 50-69 years, with weaker evidence of benefit in those aged 40-49 or 70 years and older. Magnetic resonance imaging (MRI) and ultrasonography have been evaluated in breast cancer screening, relative to, or in addition to, mammography, in selected populations; neither test has been examined in an RCT, and thus evidence of associated screening benefit is uncertain. MRI is more sensitive than mammography in screening women with suspected or proven inherited mutations of the breast cancer genes. The addition of MRI in screening this population detects 8-24 additional cancers per 1000 screens, but also significantly increases a woman's risk of being recalled for investigation or surgical biopsy for false-positive findings. In Australia, Medicare funding for MRI screening of women in specific risk groups was announced in February 2009. Ultrasonography can detect cancers not identified on mammography in asymptomatic women with dense breast tissue. Incremental ultrasound cancer detection is reported in 0.27%-0.46% of women with mammography-negative dense breasts; evidence varies on its association with false-positive findings. Computer-aided detection (CAD) is a complementary tool to mammography, prompting the reader to consider lesions on the mammogram that may represent cancer. Emerging evidence and improved CAD technology are likely to help define its role in breast screening.

Adjunctive diagnostic value of MRI in the breast radial scar

PURPOSE

We sought to identify breast magnetic resonance imaging (MRI) criteria capable of influencing the differential diagnosis between radial scars related to benign proliferative disease and those associated with breast cancer with a view to proposing breast MRI as a promising and cost-effective modality to be carried out between mammography and surgical biopsy.

MATERIALS AND METHODS

From 1998 to June 2006, we studied 20 patients with a focal architectural distortion on mammography. All patients underwent contrast-enhanced breast MRI with a T1 Philips Gyroscan scanner and the acquisition of T1-weighted fast field echo, echo planar imaging (FFE EPI) axial dynamic sequences with a slice thickness of 3 mm. During postprocessing, subtracted images were assessed for morphological features, pattern of contrast enhancement, time-intensity curve and lesion enhancement rate.

RESULTS

Breast MRI depicted 27 lesions between 7 mm and 30 mm in size. Fifteen of the 27 breast lesions showed benign features, eight showed malignant features and four were classified as suspicious. Pathological examination confirmed the benignity of all 15 lesions showing benign MRI features and revealed the benign nature of the four lesions classified as suspicious.

CONCLUSIONS

Evaluation of breast MRI showed that enhancement rate and time-intensity curve were useful only in the differential diagnosis between benign and malignant breast lesions. Our experience confirmed that breast MRI has very high sensitivity and, in particular, a negative predictive value of 100%. Breast MRI could thus be considered a useful diagnostic tool that can guide the choice between follow-up or surgical excision of radial scars.

[Retrospective study conducted in northern Finistère about the role of breast MRI in normal breast screening, experience in 51 patients]

OBJECTIVES

To study the role and indications of breast MRI in normal breast screening.

PATIENTS AND METHODS

Retrospective study of 51 patients (mean age of 51 years) conducted in northern Finistère. Each patient had a normal (BI-RADS 1 or 2) breast screening (mammography and echography). Four indications for MRI were chosen: screening of high-risk patients, high-density breasts, radio-clinical discordance, and breasts prostheses. Breast MRI were reviewed according to BI-RADS classification. Abnormalities categorized in BI-RADS 4 or 5 were confirmed histologically.

RESULTS

Thirteen patients underwent histological analysis. Nine invasive carcinomas were identified (six invasive lobular carcinomas (ILC), two mixed carcinomas, one invasive ductal carcinoma). For these patients, the reason for performing MRI was a radio-clinical discordance.

DISCUSSION AND CONCLUSION

The study demonstrates the breast MRI value for radio-clinical discordance and the key role of MRI in diagnostic challenge of ILC. In literature review, MRI has a role even if breast screening is normal: radio-clinical discordance, screening of patients with high-risk, breasts prostheses in certain cases. Breast density comes as an additional criteria to perform this exam.

Cost-effectiveness of testing for breast cancer susceptibility genes

OBJECTIVES

Genetic mutations in breast cancer susceptibility genes BRCA1/2 are associated with an increased risk of breast/ovarian cancers. Cost-effective preventive measures are available for women who test positive. The objective of this study was to determine at what risk of mutation it is cost-effective to test women for BRCA1/2 mutations.

METHODS

A semi-Markov model accrued costs and quality-adjusted life years (QALYs) annually from the societal perspective. The estimates of health-care costs, life expectancy, likelihood of obtaining a mastectomy or oophorectomy, and patient preferences for treatment and certainty about their BRCA1/2 status were based on the literature.

RESULTS

At a 10% probability of mutation (the current guideline), the test strategy generated 22.9 QALYs over the lifetime and cost $118k, while the no-test strategy generated 22.7 QALYs and cost $117k. The incremental cost-effectiveness ratio of the test strategy was $9k and the differences between costs and effects were not substantial. The test strategy remained cost-effective to a probability of mutation of 0%, as long as utility gained from a negative test result was 0.006 or greater. These results were sensitive to the frequency of inconclusive test results and utility gain from a negative test result.

CONCLUSIONS

The costs and effectiveness of both the test and no-test strategies are very similar even when there is a small probability of mutation. Current guidelines, which can be used by insurance companies to refuse coverage, could deny some women a cost-effective approach. Further research to decrease the frequency of inconclusive results could improve the cost-effectiveness of this test.

Tailored supplemental screening for breast cancer: what now and what next?

OBJECTIVE

This article reviews breast cancer risk assessment and the rationale for current screening guidelines, including when to consider using supplemental screening with MRI or sonography in addition to mammography, and discusses other emerging technologies. Radiologists can help identify women who may benefit from supplemental screening and can help to recommend when and which techniques to perform for this additional screening.

CONCLUSION

Mammography remains the mainstay of breast cancer screening. Mammography should be performed as digital imaging when possible in women with dense breasts. In women at high risk, particularly if they also have dense breasts, annual MRI is recommended, although further validation of outcomes is needed. In intermediate-risk women with dense breasts, especially those with other risk factors, and in high-risk women with dense breasts who are unable to tolerate MRI, supplemental sonography screening is an option at facilities with availability of qualified personnel. Developing technologies are not appropriate for screening at this time, although further study is encouraged.

Two mutations of BRCA2 gene at exon and splicing site in a woman who underwent oncogenetic counseling

BACKGROUND

Although most BRCA sequence variants are clearly deleterious and unequivocally pathogenetic, several are still classified as variants of unknown significance.

PATIENTS AND METHODS

We followed families undergoing oncogenetic counseling from risk identification to risk definition by genetic testing and risk management.

RESULTS

We identified two germline mutations in the BRCA2 gene in a woman with breast and ovarian cancer. One sequence alteration was 859/G>A in exon 7 (V211I). The other second sequence alteration (IVS13-2A>T) affected the splicing site in intron 13. The latter alteration is not yet listed in the Breast Cancer Information Core database. RT-PCR resulted in transcription of a sequence lacking exon 7 and a subsequent anomalous stop codon in exon 9 thereby confirming altered messenger RNA (mRNA) maturation. Amplification of the mutation in intron 13 resulted in transcription of a sequence lacking exon 14 and an anomalous stop codon in exon 15 thereby confirming altered mRNA maturation. Both mutations led to a truncated BRCA2 protein in its carboxy-terminal region.

CONCLUSION

The two BRCA2 mutations identified affect mRNA splicing fidelity and play a pathogenetic role in breast and ovarian cancer.

Conventional galactography and MR contrast galactography for diagnosing nipple discharge: preliminary results

Objective

We wanted to compare the clinical usefulness of conventional galactography and MR contrast galactography for diagnosing patients with nipple discharge.

Materials and Methods

Both conventional galactography and MR contrast galactography were performed prospectively in 16 patients. Gadopentate dimeglumine (0.1 ml) was mixed with non-ionic contrast medium (0.9 ml) to obtain a resultant volume of 1 ml and this was used for both examinations. Following conventional galactography, MR contrast galactography was performed after direct injection of contrast media into the duct.

Results

Conventional galactography and MR contrast galactography were concordant in 13 (81%) of 16 patients; the results were normal in five, ductal dilatation was noted in four and intraductal filling defects were noted in four. The remaining three (19%) patients demonstrated discordant findings on the two examinations. While conventional galactography revealed filling defects, the MR contrast galactography results were normal in two patients. The third patient had kinks-stricture on conventional galactography and MR contrast galactography showed ductal dilatation. This suggested there were false positive results for the three patients' conventional galactography, and all the three patients with discordant results underwent surgery and the histopathologic evaluation showed fibrocystic changes.

Conclusion

MR contrast galactography may be used as an alternative imaging modality for making the diagnosis of pathologic nipple discharge. However, statistically supported studies with large pools of subjects for comparing the galactography and MR contrast galactography results are needed to confirm our findings.

The American Cancer Society guidelines for breast screening with magnetic resonance imaging: an argument for genetic testing

BACKGROUND

The American Cancer Society (ACS) guidelines for screening with breast magnetic resonance imaging (MRI) recommend MRI for women who have a lifetime risk > or = 20% of developing breast cancer. Genetic testing for breast cancer gene (BRCA) mutations is offered to women who have a risk > or = 10% of carrying a mutation. The objectives of the current study were 1) to identify the number of women in a breast cancer screening population who had > or = 20% lifetime breast cancer risk and, thus, were candidates for screening MRI; and 2) to determine the number of women who had > or = 10% risk of BRCA mutation yet had <20% lifetime risk of breast cancer and, thus, may not have been identified as candidates for MRI screening.

METHODS

From 2003 to 2005, women who underwent screening mammography completed a self-administered questionnaire regarding breast cancer risk factors. For each patient, the lifetime breast cancer risk and the risk of BRCA mutation was determined by using the computerized BRCAPRO breast cancer risk-assessment model.

RESULTS

Of 18,190 women, 78 (0.43%) had > or = 20% lifetime risk of breast cancer, all of whom had > or = 10% risk of carrying a BRCA mutation. An additional 374 women (2.06%) had <20% lifetime breast cancer risk but > or = 10% risk of mutation. Overall, there were 183 (1%) predicted mutation carriers, 27 women (0.15%) who had > or = 20% lifetime risk of breast cancer, and 62 women (0.34%) who had > or = 10% risk of mutation but <20% lifetime breast cancer risk.

CONCLUSIONS

The ACS guidelines for breast MRI screening may systematically exclude MRI screening for many women who have a substantial risk for BRCA mutation. The current results demonstrated a need for greater awareness of breast cancer risk factors in the screening mammography population, so that high-risk women can be identified and given access to genetic testing and counseling regarding all risk-reducing interventions.

Breast cancer imaging: a perspective for the next decade

Breast imaging is largely indicated for detection, diagnosis, and clinical management of breast cancer and for evaluation of the integrity of breast implants. In this work, a prospective view of techniques for breast cancer detection and diagnosis is provided based on an assessment of current trends. The potential role of emerging techniques that are under various stages of research and development is also addressed. It appears that the primary imaging tool for breast cancer screening in the next decade will be high-resolution, high-contrast, anatomical x-ray imaging with or without depth information. MRI and ultrasonography will have an increasingly important adjunctive role for imaging high-risk patients and women with dense breasts. Pilot studies with dedicated breast CT have demonstrated high-resolution three-dimensional imaging capabilities, but several technological barriers must be overcome before clinical adoption. Radionuclide based imaging techniques and x-ray imaging with intravenously injected contrast offer substantial potential as a diagnostic tools and for evaluation of suspicious lesions. Developing optical and electromagnetic imaging techniques hold significant potential for physiologic information and they are likely to be of most value when integrated with or adjunctively used with techniques that provide anatomic information. Experimental studies with breast specimens suggest that phase-sensitive x-ray imaging techniques can provide edge enhancement and contrast improvement but more research is needed to evaluate their potential role in clinical breast imaging. From the technological perspective, in addition to improvements within each modality, there is likely to be a trend towards multi-modality systems that combine anatomic with physiologic information. We are also likely to transition from a standardized screening, where all women undergo the same imaging exam (mammography), to selection of a screening modality or modalities based an individual-risk or other classification.

Breast cancer screening in women at high risk using MRI

A series of prospective comparative studies have demonstrated that MRI has approximately twice the sensitivity of X-ray mammography for screening women at high familial risk of breast cancer. In these studies, lesions have often been detected at an early stage, with disease being small and predominantly node negative. The diagnostic features in relation to risk and the biological behaviour of disease with risk category and age are being evaluated. The results of these studies have resulted in revised recommendations for screening for women at high risk of breast cancer. In this article, the results of the UK Magnetic Resonance Imaging in Breast Cancer Screening (MARIBS) study of MRI screening are described, and compared with results from other studies. Risk factors identifying women who would benefit from MRI screening are discussed, MRI measurement methods are described, and the results of studies evaluating MRI and mammographic lesions in different risk groups are reviewed. Recommendations for screening women at high risk of breast cancer published by the American Cancer Society and from the National Institute for Health and Clinical Excellence (NICE) in the UK are summarised.

Breast cancer risks in women with a family history of breast or ovarian cancer who have tested negative for a BRCA1 or BRCA2 mutation

Genetic testing for mutations in BRCA1 and BRCA2 is available in Canada for women with a significant family history of breast cancer. For the majority of tested women, a BRCA1 or BRCA2 mutation is not found, and counselling regarding breast cancer risk is based on the review of the pedigree. In this prospective study, we estimate breast cancer risks in women with a family history of breast cancer and for whom the proband tested negative for a mutation in BRCA1 or BRCA2. Families with two or more breast cancers under the age of 50 years, or with three cases of breast cancer at any age, and who tested negative for a BRCA1 or BRCA2 mutation were identified. Follow-up information on cancer status was collected on all first-degree relatives of breast cancer cases. The standardised incidence ratios (SIRs) for breast cancer were calculated by dividing the observed numbers of breast cancer by the expected numbers of breast cancers, based on the rates in the provincial cancer registries. A total of 1492 women from 365 families were included in the analyses. The 1492 first-degree relatives of breast cancer cases contributed 9109 person-years of follow-up. Sixty-five women developed breast cancer, compared to 15.2 expected number (SIR=4.3). The SIR was highest for women under the age of 40 (SIR=14.9) years and decreased with increasing age. However, the absolute risk was higher for women between the age of 50 and 70 (1% per year) years than for women between 30 and 50 (0.4% per year) years of age. There was no elevated risk for ovarian, colon or any other form of cancer. Women with a significant family history of breast cancer (ie, two or more breast cancers under the age of 50 years, or three or more breast cancers at any age), but who test negative for BRCA mutations have approximately a four-fold risk of breast cancer. Women in these families may be candidates for tamoxifen chemoprevention and/or intensified breast screening with an MRI.

Can genetic testing guide treatment in breast cancer?

In the last 15 years, our understanding of genes that predispose to breast cancer has increased enormously. Germline alleles have been identified that have a modest effect on the risk of breast cancer, but there remain only a handful of genes in which mutation substantially elevates the risk of breast cancer. These include BRCA1, BRCA2, TP53 and PTEN. Whilst breast cancer occurring in patients in Li-Fraumeni and Cowden's syndrome families is of great importance, the more frequent scenario is that of women, or indeed of men, presenting with breast cancer with an underlying germline mutation in BRCA1 or BRCA2. Should these individuals be treated differently because they have had a breast cancer or are at risk of the disease because of a BRCA1 or BRCA2 mutation? In this review, we consider whether BRCA1 or BRCA2 mutation influences the choice of breast screening and breast cancer prevention strategies. Furthermore, for women with an established breast cancer whether their mutation directly influences (1) baseline prognosis, (2) the results of local surgical and radiation therapy, (3) the benefits from adjuvant systemic therapy and finally (4) whether selection or avoidance of particular systemic agents is guided by the presence of a BRCA1 or BRCA2 germline mutation?

Breast cancer screening in high risk women

Women who are at a significantly raised risk of developing breast cancer should be assessed by a medical geneticist to confirm their history, counselled as to appropriate management and offered breast screening. Currently mammography with magnetic resonance imaging is considered the optimal method of early detection of breast cancer in these women. While there is no evidence of mortality benefit there is evidence from surrogate markers that this intervention is worthwhile and cost effective. National recommendations have been produced by the National Institute of Clinical Excellence in the UK and also by the American Cancer Society.

Gadobenate dimeglumine as a contrast agent for dynamic breast magnetic resonance imaging: effect of higher initial enhancement thresholds on diagnostic performance

RATIONALE AND OBJECTIVE

Gadobenate dimeglumine (Gd-BOPTA), a high-relaxivity contrast agent, has been recently proposed for dynamic MR imaging of the breast. The objective of this study was to optimize the diagnostic performance of Gd-BOPTA-enhanced dynamic breast MR imaging by using adjusted initial enhancement thresholds.

METHODS

Thirty-four patients with 36 breast lesions (malignant/benign = 28/8) underwent dynamic breast MRI with 0.1 mmol/kg Gd-BOPTA and 120-second time resolution. A score system based on shape (round/oval/lobular = 0; linear/dendritic/stellate = 1), margins (defined = 0; undefined = 1), pattern (homogeneous = 0; inhomogeneous = 1; rim = 2), kinetics (continuous = 0; plateau = 1; washout = 2), and initial enhancement was used. Initial enhancement was determined with standard (<50% = 0; 50%-100% = 1; >100% = 2) and adjusted (<100% = 0; 100%-240% = 1; >240% = 2) thresholds. Scores of 0 to 3 indicated benign lesions and scores of 4 to 8 malignant lesions. Diagnostic performance was assessed in terms of sensitivity, specificity, positive and negative predictive values, and overall accuracy.

RESULTS

The initial enhancement was >100% for 26 malignant and 7 benign lesions and >240% for 16 and 1 lesions, respectively. The overall score was 5.89 +/- 1.34 with standard thresholds and 5.50 +/- 1.53 with adjusted thresholds (P = 0.003) for cancers, 4.00 +/- 1.93 and 3.25 +/- 1.75 (P = 0.028) for benign lesions, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy was 96%, 13%, 79%, 50%, and 78%, respectively, with standard thresholds and 96%, 75%, 93%, 86%, and 92%, respectively, with adjusted thresholds. A ductal carcinoma in situ was false negative whereas a fat necrosis and a papilloma were false positive with both thresholds. Three fibroadenomas, 1 adenosis, and 1 fibrosis were false positive with standard thresholds but true negatives with adjusted thresholds.

CONCLUSIONS

Lesion characterization with Gd-BOPTA requires higher thresholds for initial enhancement than those used with conventional Gd-chelates, leading to improved specificity, predictive values, and accuracy.

[Magnetic resonance imaging in preoperative staging for breast cancer: pros and contras]

In oncologic patients, staging of the disease extent is of paramount importance. Imaging studies are used to decide whether the patient is a surgical candidate; if this is the case, imaging is used for detailed planning of the surgical procedure itself. Even in patients with limited prognosis, the first priority is always to achieve clear margins. Due to the widespread use of screening mammography, breast cancers are among the few cancers that are almost always diagnosed in an operable stage and are operated on with curative intention. It is well established that magnetic resonance imaging (MRI) is far superior to mammography (with and without concomitant ultrasound) for mapping the local extent of breast cancer. Accordingly, there is good reason to suggest that a pre-operative breast MRI should be considered an integral part of breast conserving treatment. Still, it is only rarely used in clinical practice. Arguments against its use are: Its high costs, allegedly high number of false positive findings, lack of MR-guided breast biopsy facilities, lack of evidence from randomized prospective trials and, notably, fear of "overtreatment". This paper discusses the reservations against staging MRI and weighs them against its clinical advantages. The point is made that radiologists as well as breast surgeons should be aware of the possibility of overtreatment, i.e. unnecessary mastectomy for very small, "MRI-only" multicentric cancer foci that would indeed be sufficiently treated by radiation therapy. There is a clear need to adapt the guidelines established for treatment of mammography-diagnosed multicentric breast cancer to account for the additional use of MRI for staging. Until these guidelines are available, the management of additional, "MRI-only" diagnosed small multicentric cancer manifestations must be decided on wisely and with caution. MRI for staging may only be done in institutions that can also offer an MR-guided tissue sampling, preferably by MR-guided vacuum assisted biopsy, to provide pre-operative histological proof of lesions visible by breast MRI alone.

Imaging studies for the early detection of breast cancer

INTRODUCTION

The effectiveness of mammographic screening has been proven at evidence level 1A. Mammography offers the best ratio of benefits to side effects of any screening method tested to date. In this literature review, we ask whether early detection might be improved still further by combining mammography with other imaging modalities.

METHODS

The authors performed a selective literature search for combined key words in the Medline and Cochrane Library databases from 1/2000 to 11/2007, screened all titles, and evaluated the full text of all original articles. We selected articles for further analysis according to systematic criteria (minimum numbers, avoidance of overlap) and also considered published guidelines.

RESULTS

No screening studies of comparable size to those for mammography are available for ultrasound or MRI. Smaller studies have indicated that the use of these two modalities might lead to the detection of additional cancers in selected subgroups. For mass screening an increase in the detection rate of 10% to 15% might become possible. This increase would probably be associated with a tripling of the breast biopsy rate, compared to mammography alone. The number of indeterminate cases in which short-term follow-up (i.e., at 6 months) would be recommended would increase roughly tenfold with MRI, and to an unknown extent with ultrasound. The related quality-assurance issues remain to be addressed.

DISCUSSION

Randomized controlled studies are needed for a realistic assessment of the achievable benefits and unavoidable side effects of combined screening. For women whose risk of breast cancer is not elevated, mammography remains the standard screening method.

The role of magnetic resonance imaging in screening women at high risk of breast cancer

Most women at very high risk of breast cancer because of a mutation in the genes BRCA1 or BRCA2, or a very strong family history of breast cancer, opt for intensive breast screening rather than bilateral prophylactic mastectomy. Annual screening mammography has low sensitivity in this population in part because of the greater breast density and faster tumor growth of younger women, resulting in cancers being detected at a suboptimal stage. In 11 prospective comparative studies, the addition of annual contrast-enhanced magnetic resonance imaging (MRI) of the breast to mammography demonstrated more than 90% sensitivity, more than twice that of mammography alone. False-positive rates were higher with the addition of MRI, but specificity improved on successive rounds of screening. Although survival data are not yet available, the stage distribution of these tumors predicts a significant reduction in breast cancer mortality rate compared with that of screening without MRI. Accordingly, annual MRI plus mammography is now the standard of care for screening women aged 30 years or older who are known or likely to have inherited a strong predisposition to breast cancer (based on the above evidence) and for women who received radiation therapy to the chest before the age of 30 years (based on expert opinion). Further research is necessary to define the optimal screening schedule for different subgroups. Formal studies of other high-risk populations (eg, biopsy showing lobular neoplasia or atypical ductal hyperplasia, dense breasts, and personal history of breast cancer at a young age) should be done before MRI screening is routinely adopted for these women.

A review of current evidence-based clinical applications for breast magnetic resonance imaging

Magnetic resonance imaging (MRI) is an important new tool for imaging of the breast. MRI has now been demonstrated to be the most sensitive imaging method for detecting breast carcinoma, allowing depiction of cancers that are occult on mammography, ultrasound, and clinical breast examination. This is tempered by imperfect specificity due to overlap in the features of benign and malignant lesions, and by higher examination cost and more limited availability compared to other breast imaging tests. This article describes the current evidence-based clinical indications for use of breast MRI. Specifically, MRI has been shown to be advantageous for cancer assessment for screening patients at high risk, evaluating patients with a new breast cancer diagnosis, monitoring patients undergoing neoadjuvant chemotherapy, and evaluating patients with metastatic axillary adenocarcinoma and unknown primary site. This tool has also been shown to be useful for the evaluation of silicone breast implant integrity. Employment of breast MRI as a problem solving technique for equivocal mammographic or clinical findings is controversial. For each of these clinical applications, the evidence regarding the diagnostic accuracy of breast MRI will be reviewed. An understanding of the current evidence will facilitate the most appropriate utilization of this important medical resource.

Combined screening with ultrasound and mammography vs mammography alone in women at elevated risk of breast cancer

CONTEXT

Screening ultrasound may depict small, node-negative breast cancers not seen on mammography.

OBJECTIVE

To compare the diagnostic yield, defined as the proportion of women with positive screen test results and positive reference standard, and performance of screening with ultrasound plus mammography vs mammography alone in women at elevated risk of breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

From April 2004 to February 2006, 2809 women, with at least heterogeneously dense breast tissue in at least 1 quadrant, were recruited from 21 sites to undergo mammographic and physician-performed ultrasonographic examinations in randomized order by a radiologist masked to the other examination results. Reference standard was defined as a combination of pathology and 12-month follow-up and was available for 2637 (96.8%) of the 2725 eligible participants.

MAIN OUTCOME MEASURES

Diagnostic yield, sensitivity, specificity, and diagnostic accuracy (assessed by the area under the receiver operating characteristic curve) of combined mammography plus ultrasound vs mammography alone and the positive predictive value of biopsy recommendations for mammography plus ultrasound vs mammography alone.

RESULTS

Forty participants (41 breasts) were diagnosed with cancer: 8 suspicious on both ultrasound and mammography, 12 on ultrasound alone, 12 on mammography alone, and 8 participants (9 breasts) on neither. The diagnostic yield for mammography was 7.6 per 1000 women screened (20 of 2637) and increased to 11.8 per 1000 (31 of 2637) for combined mammography plus ultrasound; the supplemental yield was 4.2 per 1000 women screened (95% confidence interval [CI], 1.1-7.2 per 1000; P = .003 that supplemental yield is 0). The diagnostic accuracy for mammography was 0.78 (95% CI, 0.67-0.87) and increased to 0.91 (95% CI, 0.84-0.96) for mammography plus ultrasound (P = .003 that difference is 0). Of 12 supplemental cancers detected by ultrasound alone, 11 (92%) were invasive with a median size of 10 mm (range, 5-40 mm; mean [SE], 12.6 [3.0] mm) and 8 of the 9 lesions (89%) reported had negative nodes. The positive predictive value of biopsy recommendation after full diagnostic workup was 19 of 84 for mammography (22.6%; 95% CI, 14.2%-33%), 21 of 235 for ultrasound (8.9%, 95% CI, 5.6%-13.3%), and 31 of 276 for combined mammography plus ultrasound (11.2%; 95% CI. 7.8%-15.6%).

CONCLUSIONS

Adding a single screening ultrasound to mammography will yield an additional 1.1 to 7.2 cancers per 1000 high-risk women, but it will also substantially increase the number of false positives.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00072501.

Breast MRI for cancer detection and characterization: a review of evidence-based clinical applications

RATIONALE AND OBJECTIVES

Breast MRI is an important new tool in the imaging armamentarium for the detection and characterization of breast carcinoma. Understanding the evidence-supported benefits and potential harms of breast MRI is important to ensure the appropriate utilization of this medical resource.

MATERIALS AND METHODS

This article reviews the clinical settings in which MRI for breast cancer assessment has been shown to be advantageous. The evidence regarding the diagnostic accuracy of MRI and the impact of this imaging tool on clinical outcomes are described. Novel breast MRI techniques which may lead to future improvements in performance are discussed.

RESULTS

Breast MRI has been shown in multiple studies to be advantageous for screening patients at high risk, evaluating patients with a new breast cancer diagnosis, monitoring treatment response in patients undergoing neoadjuvant chemotherapy and evaluating patients with metastatic axillary adenocarcinoma and unknown primary site. Among the limitations of MRI are its high cost and modest specificity resulting in false positive examinations.

CONCLUSIONS

When used in evidence-supported clinical settings, the high sensitivity of MRI results in earlier cancer detection or greater accuracy of detection compared to existing tests for breast carcinoma. Further scientific endeavors are crucial to optimize the future performance and application of breast MRI.