Elizabeth A. Morris

American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography.

New evidence on breast Magnetic Resonance Imaging (MRI) screening has become available since the American Cancer Society (ACS) last issued guidelines for the early detection of breast cancer in 2003. A guideline panel has reviewed this evidence and developed new recommendations for women at different defined levels of risk. Screening MRI is recommended for women with an approximately 20–25% or greater lifetime risk of breast cancer, including women with a strong family history of breast or ovarian cancer and women who were treated for Hodgkin disease. There are several risk subgroups for which the available data are insufficient to recommend for or against screening, including women with a personal history of breast cancer, carcinoma in situ, atypical hyperplasia, and extremely dense breasts on mammography. Diagnostic uses of MRI were not considered to be within the scope of this review.

Locally Advanced Breast Cancer: MR Imaging for Prediction of Response to Neoadjuvant Chemotherapy—Results from ACRIN 6657/I-SPY TRIAL

PURPOSE To compare magnetic resonance (MR) imaging findings and clinical assessment for prediction of pathologic response to neoadjuvant chemotherapy (NACT) in patients with stage II or III breast cancer. MATERIALS AND METHODS The HIPAA-compliant protocol and the informed consent process were approved by the American College of Radiology Institutional Review Board and local-site institutional review boards. Women with invasive breast cancer of 3 cm or greater undergoing NACT with an anthracycline-based regimen, with or without a taxane, were enrolled between May 2002 and March 2006. MR imaging was performed before NACT (first examination), after one cycle of anthracyline-based treatment (second examination), between the anthracycline-based regimen and taxane (third examination), and after all chemotherapy and prior to surgery (fourth examination). MR imaging assessment included measurements of tumor longest diameter and volume and peak signal enhancement ratio. Clinical size was also recorded at each time point. Change in clinical and MR imaging predictor variables were compared for the ability to predict pathologic complete response (pCR) and residual cancer burden (RCB). Univariate and multivariate random-effects logistic regression models were used to characterize the ability of tumor response measurements to predict pathologic outcome, with area under the receiver operating characteristic curve (AUC) used as a summary statistic. RESULTS Data in 216 women (age range, 26-68 years) with two or more imaging time points were analyzed. For prediction of both pCR and RCB, MR imaging size measurements were superior to clinical examination at all time points, with tumor volume change showing the greatest relative benefit at the second MR imaging examination. AUC differences between MR imaging volume and clinical size predictors at the early, mid-, and posttreatment time points, respectively, were 0.14, 0.09, and 0.02 for prediction of pCR and 0.09, 0.07, and 0.05 for prediction of RCB. In multivariate analysis, the AUC for predicting pCR at the second imaging examination increased from 0.70 for volume alone to 0.73 when all four predictor variables were used. Additional predictive value was gained with adjustments for age and race. CONCLUSION MR imaging findings are a stronger predictor of pathologic response to NACT than clinical assessment, with the greatest advantage observed with the use of volumetric measurement of tumor response early in treatment.

Determination of the presence and extent of pure ductal carcinoma in situ by mammography and magnetic resonance imaging.

Abstract:  The purpose of this study was to compare the ability of magnetic resonance imaging (MRI) and mammography to determine the presence and extent of ductal carcinoma in situ (DCIS). Retrospective review of medical records of women who underwent MRI and mammographic examination during a 23‐month period revealed 39 sites of pure DCIS in 33 breasts of 32 women. No invasive or microinvasive tumor was found. Women ranged in age from 34 to 79 years (mean age 53 years). In these 33 breasts, both MRI and mammography were done before surgery. Reports and images of mammography and MRI were reviewed to determine if each study was positive for the presence of single or multiple sites of DCIS and the imaging patterns associated with these sites. Of 33 breasts involved, DCIS was discovered by MRI alone in 21 (64%), by both MRI and mammography in 8 (24%), and by mammography alone in 1 (3%); in 3 breasts (9%), DCIS was found at mastectomy without findings on mammography or MRI. MRI had significantly higher sensitivity than mammography for DCIS detection (29/33 = 88% versus 9/33 = 27%, p < 0.00001). Multiple sites of disease were present in five breasts; these were better demonstrated with MRI in three, mammography in one, and equally by both in one. The predominant enhancement pattern of DCIS on MRI was linear/ductal in 18 of 29 breasts (62%); mammography found calcifications associated with DCIS in 8 of 9 (89%). The nuclear grade of DCIS found with MRI and mammography was similar; size of lesions was larger on MRI; breast density did not impact results. In this study, MRI was significantly more sensitive than mammography in DCIS detection. In women with known or suspected DCIS, MRI may have an important role to play in assessing the extent of disease in the breast.

Background Parenchymal Enhancement at Breast MR Imaging and Breast Cancer Risk

PURPOSE To examine the relationships between breast cancer and both amount of fibroglandular tissue (FGT) and level of background parenchymal enhancement (BPE) at magnetic resonance (MR) imaging. MATERIALS AND METHODS A waiver of authorization was granted by the institutional review board for this retrospective HIPAA-compliant study. Among 1275 women who underwent breast MR imaging screening between December 2002 and February 2008, 39 breast carcinoma cases were identified. Two comparisons were performed: In one comparison, two normal controls--those of the women with negative (benign) findings at breast MR imaging--were matched to each breast cancer case on the basis of age and date of MR imaging. In the second comparison, one false-positive control--that of a woman with suspicious but nonmalignant findings at MR imaging--was similarly matched to each breast cancer case. Two readers independently rated the level of MR imaging-depicted BPE and the amount of MR imaging-depicted FGT by using a categorical scale: BPE was categorized as minimal, mild, moderate, or marked, and FGT was categorized as fatty, scattered, heterogeneously dense, or dense. RESULTS Compared with the odds ratio (OR) for a normal control, the OR for breast cancer increased significantly with increasing BPE: The ORs for moderate or marked BPE versus minimal or mild BPE were 10.1 (95% confidence interval [CI]: 2.9, 35.3; P < .001) and 3.3 (95% CI: 1.3, 8.3; P = .006) for readers 1 and 2, respectively. Similar odds were seen when the false-positive controls were compared with the breast cancer cases: The ORs for moderate or marked BPE versus minimal or mild BPE were 5.1 (95% CI: 1.4, 19.1; P = .005) and 3.7 (95% CI: 1.2, 11.2; P = .013) for readers 1 and 2, respectively. The breast cancer odds also increased with increasing FGT, but the BPE findings remained significant after adjustment for FGT. CONCLUSION Increased BPE is strongly predictive of breast cancer odds.

MRI for breast cancer screening, diagnosis, and treatment

MRI is used widely both for screening women who are at increased risk of breast cancer and for treatment selection. Prospective studies confirm that MRI screening of women with known or suspected genetic mutation results in a higher sensitivity for cancer detection than does mammography. However, survival data are not available. In women with breast cancer, MRI detects cancer not identified with other types of screening. In two randomised trials, this increased sensitivity did not translate into improved selection of surgical treatment or a reduction in the number of operations. Data for longer-term outcomes such as ipsilateral breast tumour recurrence rates and contralateral breast cancer incidence are scarce, but to date do not show clear benefit for MRI. MRI is better than other methods of assessing the response to neoadjuvant chemotherapy, and is helpful in identifying the primary tumour in patients who present with axillary adenopathy.

Does Size Matter? Positive Predictive Value of MRI-Detected Breast Lesions as a Function of Lesion Size

OBJECTIVE The purpose of this study was to determine the impact of lesion size on the positive predictive value (PPV) of biopsy in MRI-detected breast lesions. MATERIALS AND METHODS A retrospective review was performed of 666 consecutive nonpalpable, mammographically occult lesions that had MRI-guided localization. MRI examinations were performed using a 1.5-T magnet. Lesions were measured by the interpreting radiologist before biopsy. Malignancy rate versus lesion size was determined. RESULTS The median MRI lesion size was 1 cm (range, 0.3-7.0 cm). Malignancy was present in 149/666 (22%) lesions, of which 80 (54%) were ductal carcinoma in situ (DCIS), 66 (44%) were invasive cancer, and three (2%) were lymphoma. The frequency of malignancy increased significantly (p = 0.0005) with lesion size, with malignancy found in one (3%) of 37 lesions less than 5 mm, 44 (17%) of 254 lesions 5-9 mm, 37 (25%) of 151 lesions 10-14 mm, 21 (28%) of 74 lesions 15-19 mm, and 46 (31%) of 150 lesions 20 mm or larger. Lesions less than 5 mm accounted for 37 (6%) of 666 lesions that had a biopsy and one (< 1%) of 149 cancers (one DCIS). Among lesions less than 10 mm, the likelihood of malignancy was highest in postmenopausal women (22% malignant) and in the extent of disease setting (22% malignant), and lowest in premenopausal women (10% malignant) and in the high-risk screening setting (10% malignant). CONCLUSION The PPV of biopsy for lesions identified at breast MRI using a 1.5-T magnet significantly increased with increasing lesion size. Biopsy is rarely necessary for lesions smaller than 5 mm because of their low (3%) likelihood of cancer. Further work is needed to develop an algorithm that uses size in addition to other patient and lesion factors to guide biopsy recommendations for MRI-detected breast lesions.

Systematic Review: Surveillance for Breast Cancer in Women Treated With Chest Radiation for Childhood, Adolescent, or Young Adult Cancer

BACKGROUND Women treated with therapeutic chest radiation may develop breast cancer. PURPOSE To summarize breast cancer risk and breast cancer surveillance in women after chest radiation for pediatric or young adult cancer. DATA SOURCES Studies from MEDLINE, EMBASE, the Cochrane Library, and CINAHL (1966 to December 2008). STUDY SELECTION Articles were selected to answer any of 3 questions: What is the incidence and excess risk for breast cancer in women after chest radiation for pediatric or young adult cancer? For these women, are the clinical characteristics of breast cancer and the outcomes after therapy different from those of women with sporadic breast cancer in the general population? What are the potential benefits and harms associated with breast cancer surveillance among women exposed to chest radiation? DATA EXTRACTION Three investigators independently extracted data and assessed study quality. DATA SYNTHESIS Standardized incidence ratios ranged from 13.3 to 55.5; cumulative incidence of breast cancer by age 40 to 45 years ranged from 13% to 20%. Risk for breast cancer increased linearly with chest radiation dose. Available limited evidence suggests that the characteristics of breast cancer in these women and the outcomes after diagnosis are similar to those of women in the general population; mammography can detect breast cancer, although sensitivity is limited. LIMITATION The quality of evidence for key questions 2 and 3 is limited by substantial study heterogeneity, variation in study design, and small sample size. CONCLUSION Women treated with chest radiation have a substantially elevated risk for breast cancer at a young age, which does not seem to plateau. In this high-risk population, there seems to be a benefit associated with early detection. Further research is required to better define the harms and benefits of lifelong surveillance.

Magnetic Resonance Imaging Facilitates Breast Conservation for Occult Breast Cancer

Introduction: Occult primary breast cancer, i.e., isolated axillary adenocarcinoma without detectable tumor in the breast by either physical exam or mammography, represents up to 1% of operable breast cancer. Modified radical mastectomy (MRM) is generally the accepted treatment for this condition although tumor is identified in only two-thirds of mastectomy specimens. Breast magnetic resonance imaging (MRI) can identify occult breast carcinoma and may direct therapy. This study examined the ability of breast MRI to detect occult breast cancer and to facilitate breast conservation therapy.Methods: Forty women with biopsy-proven metastatic adenocarcinoma to an axillary lymph node and no evidence of primary cancer were studied. All patients had a physical examination, mammography, and MRI of the breast. Using a dedicated breast coil, MRI imaging was performed with and without gadolinium enhancement. Positive MRI scans were compared with histopathologic findings at the time of operation (n 5 21).Results: MRI identified the primary breast lesion in 28 of 40 women (70%). Of these 28 patients, 11 had MRM, 11 had lumpectomy/axillary lymph node dissection (ALND)/radiotherapy (XRT), 2 had ALND/XRT alone, and 4 had no local treatment secondary to stage IV disease. Two women initially treated with lumpectomy/ALND subsequently had mastectomy for positive margins. Of the women with positive MRI who had breast surgery, 21 of 22 (95%) had tumor within the surgical specimen. Twelve women had negative MRI of the breast. Five of these 12 underwent MRM, of whom 4 had no tumor in the mastectomy specimen. The remaining 7 patients had ALND and whole breast radiation (ALND/XRT) (n 5 5), or were observed (n 5 2). Overall, 18 of 34 women surgically treated had MRM, while 16 (47%) preserved their breast. Tumor yield for patients having breast surgery was 81%.Conclusions: MRI of the breast can identify occult breast cancer in many patients and may facilitate breast conservation in select women. Negative breast MRI predicts low tumor yield at mastectomy.

Diagnostic breast MR imaging: current status and future directions.

Breast MRI has become an integral component in breast imaging. Indications have become clearer and better defined. Guidelines and recommendations are evolving and many are recognized and published. Future applications are exciting and may possibly improve our ability to diagnose breast cancer, improving the patients treatment options and ultimately patient outcome.

Bilateral Contrast-enhanced Dual-Energy Digital Mammography: Feasibility and Comparison with Conventional Digital Mammography and MR Imaging in Women with Known Breast Carcinoma

PURPOSE To determine feasibility of performing bilateral dual-energy (DE) contrast agent-enhanced (CE) digital mammography and to evaluate its performance compared with conventional digital mammography and breast magnetic resonance (MR) imaging in women with known breast cancer. MATERIALS AND METHODS This study was approved by the institutional review board and was HIPAA compliant. Written informed consent was obtained. Patient accrual began in March 2010 and ended in August 2011. Mean patient age was 49.6 years (range, 25-74 years). Feasibility was evaluated in 10 women with newly diagnosed breast cancer who were injected with 1.5 mL per kilogram of body weight of iohexol and imaged between 2.5 and 10 minutes after injection. Once feasibility was confirmed, 52 women with newly diagnosed cancer who had undergone breast MR imaging gave consent to undergo DE CE digital mammography. Positive findings were confirmed with pathologic findings. RESULTS Feasibility was confirmed with no adverse events. Visualization of tumor enhancement was independent of timing after contrast agent injection for up to 10 minutes. MR imaging and DE CE digital mammography both depicted 50 (96%) of 52 index tumors; conventional mammography depicted 42 (81%). Lesions depicted by using DE CE digital mammography ranged from 4 to 67 mm in size (median, 17 mm). DE CE digital mammography depicted 14 (56%) of 25 additional ipsilateral cancers compared with 22 (88%) of 25 for MR imaging. There were two false-positive findings with DE CE digital mammography and 13 false-positive findings with MR imaging. There was one contralateral cancer, which was not evident with either modality. CONCLUSION Bilateral DE CE digital mammography was feasible and easily accomplished. It was used to detect known primary tumors at a rate comparable to that of MR imaging and higher than that of conventional digital mammography. DE CE digital mammography had a lower sensitivity for detecting additional ipsilateral cancers than did MR imaging, but the specificity was higher.