Phoebe E. Freer

Addition of Tomosynthesis to Conventional Digital Mammography: Effect on Image Interpretation Time of Screening Examinations

PURPOSE To determine the effect of implementing a screening tomosynthesis program on real-world clinical performance by quantifying differences between interpretation times for conventional screening mammography and combined tomosynthesis and mammography for multiple participating radiologists with a wide range of experience in a large academic center. MATERIALS AND METHODS In this HIPAA-compliant, institutional review board-approved study, 10 radiologists prospectively read images from screening digital mammography or screening combined tomosynthesis and mammography examinations for 1-hour-long uninterrupted sessions. Images from 3665 examinations (1502 combined and 2163 digital mammography) from July 2012 to January 2013 were interpreted in at least five sessions per radiologist per modality. The number of cases reported during each session was recorded for each reader. The experience level for each radiologist was also correlated to the average number of cases reported per hour. Analysis of variance was used to assess the number of studies interpreted per hour. A linear regression model was used to evaluate correlation between breast imaging experience and time taken to interpret images from both modalities. RESULTS The mean number of studies interpreted in hour was 23.8 ± 0.55 (standard deviation) (range, 14.4-40.4) for combined tomosynthesis and mammography and 34.0 ± 0.55 (range, 20.4-54.3) for digital mammography alone. A mean of 10.2 fewer studies were interpreted per hour during combined tomosynthesis and mammography compared with digital mammography sessions (P < .0001). The mean interpretation time was 2.8 minutes ± 0.9 (range, 1.5-4.2 minutes) for combined tomosynthesis and mammography and 1.9 minutes ± 0.6 (range, 1.1-3.0) for digital mammography; interpretation time with combined tomosynthesis and mammography was 0.9 minute longer (47% longer) compared with digital mammography alone (P < .0001). With the increase in years of breast imaging experience, the overall additional time required to read images from combined tomosynthesis and mammography examinations decreased (R(2) = 0.52, P = .03). CONCLUSION Addition of tomosynthesis to mammography results in increased time to interpret images from screening examinations compared with time to interpret images from conventional digital mammography alone.

Basal Subtype of Invasive Breast Cancer is Associated with a Higher Risk of True Recurrence after Conventional Breast-Conserving Therapy

PURPOSE To determine whether breast cancer subtype is associated with patterns of ipsilateral breast tumor recurrence (IBTR), either true recurrence (TR) or elsewhere local recurrence (ELR), among women with pT1-T2 invasive breast cancer (IBC) who receive breast-conserving therapy (BCT). METHODS AND MATERIALS From Jan 1998 to Dec 2003, 1,223 women with pT1-T2N0-3 IBC were treated with BCT (lumpectomy plus whole-breast radiation). Ninety percent of patients received adjuvant systemic therapy, but none received trastuzumab. Biologic cancer subtypes were approximated by determining estrogen receptor-positive (ER+), progesterone receptor-positive (PR+), and human epidermal growth factor receptor-2-positive (HER-2+) expression, classified as luminal A (ER+ or PR+ and HER-2 negative [HER-2-]), luminal B (ER+ or PR+ and HER-2+), HER-2 (ER- and PR- and HER-2+), and basal (ER- and PR- and HER-2- ) subtypes. Imaging, pathology, and operative reports were reviewed by two physicians independently, including an attending breast radiologist. Readers were blinded to subtype and outcome. TR was defined as IBTR within the same quadrant and within 3 cm of the primary tumor. All others were defined as ELR. RESULTS At a median follow-up of 70 months, 24 patients developed IBTR (5-year cumulative incidence of 1.6%), including 15 TR and 9 ELR patients. At 5 years, basal (4.4%) and HER-2 (9%) subtypes had a significantly higher incidence of TR than luminal B (1.2%) and luminal A (0.2%) subtypes (p < 0.0001). On multivariate analysis, basal subtype (hazard ratio [HR], 4.8, p = 0.01), younger age at diagnosis (HR, 0.97; p = 0.05), and increasing tumor size (HR, 2.1; p = 0.04) were independent predictors of TR. Only younger age (HR, 0.95; p = 0.01) significantly predicted for ELR. CONCLUSIONS Basal and HER-2 subtypes are significantly associated with higher rates of TR among women with pT1-T2 IBC after BCT. Younger age predicts for both TR and ELR. Strategies to reduce TR in basal breast cancers, such as increased boost doses, concomitant radiation and chemotherapy, or targeted therapy agents, should be explored.

Accelerated Partial Breast Irradiation With Low-Dose- Rate Interstitial Implant Brachytherapy After Wide Local Excision: 12-Year Outcomes From a Prospective Trial

PURPOSE To evaluate the long-term toxicity, cosmesis, and local control of accelerated partial breast irradiation with implant brachytherapy after wide local excision for Stage T1N0 breast cancer (BCa). MATERIALS AND METHODS Between 1997 and 2001, 50 patients with Stage T1N0M0 BCa were treated in a Phase I-II protocol using low-dose-rate accelerated partial breast irradiation with implant brachytherapy after wide local excision and lymph node surgery. The total dose was escalated in three groups: 50 Gy (n = 20), 55 Gy (n = 17), and 60 Gy (n = 13). Patient- and physician-assessed breast cosmesis, patient satisfaction, toxicity, mammographic abnormalities, repeat biopsies, and disease status were prospectively evaluated at each visit. Kendalls tau (τ(β)) and logistic regression analyses were used to correlate outcomes with dose, implant volume, patient age, and systemic therapy. RESULTS The median follow-up period was 11.2 years (range, 4-14). The patient satisfaction rate was 67%, 67% reported good-excellent cosmesis, and 54% had moderate-severe fibrosis. Higher dose was correlated with worse cosmetic outcome (τ(β) 0.6, p < .0001), lower patient satisfaction (τ(β) 0.5, p < .001), and worse fibrosis (τ(β) 0.4, p = .0024). Of the 50 patients, 35% had fat necrosis and 34% developed telangiectasias ≥1 cm(2). Grade 3-4 late skin and subcutaneous toxicities were seen in 4 patients (9%) and 6 patients (13%), respectively, and both correlated with higher dose (τ(β) 0.3-0.5, p ≤ .01). One patient had Grade 4 skin ulceration and fat necrosis requiring surgery. Mammographic abnormalities were seen in 32% of the patients, and 30% underwent repeat biopsy, of which 73% were benign. Six patients had ipsilateral breast recurrence: five elsewhere in the breast, and one at the implant site. One patient died of metastatic BCa after recurrence. The 12-year actuarial local control, recurrence-free survival, and overall survival rate was 85% (95% confidence interval, 70-97%), 72% (95% confidence interval, 54-86%), and 87% (95% confidence interval, 73-99%), respectively. CONCLUSION Low-dose-rate accelerated partial breast irradiation with implant brachytherapy provides acceptable local control in select early-stage BCa patients. However, treatment-related toxicity and cosmetic complications were significant with longer follow-up and at higher doses.

Preoperative Tomosynthesis-guided Needle Localization of Mammographically and Sonographically Occult Breast Lesions.

PURPOSE To assess the feasibility and accuracy of digital breast tomosynthesis (DBT)-guided needle localization for DBT-detected suspicious abnormalities not visualized with other modalities and to analyze the imaging and pathologic characteristics of abnormalities detected only with DBT to determine the positive predictive value for malignancy. MATERIALS AND METHODS This HIPAA-compliant study was approved by the institutional review board, and the requirement to obtain informed consent was waived. A retrospective query of the imaging database identified 34 consecutive women (average age, 55 years; age range, 28-84 years) with 36 lesions who underwent DBT-guided needle localization between April 2011 and January 2013 with use of commercially available equipment. Imaging findings and medical records were reviewed. Findings that were attributable to previous surgical changes were classified as benign or probably benign and excluded from analysis because the lesions did not proceed to localization. RESULTS Architectural distortion was the imaging finding identified in all 36 abnormalities (100%). Findings from pathologic examination after the first attempt at localization were concordant with those from imaging in 35 of the 36 lesions (97%), which is suggestive of appropriate sampling. Histologic findings were malignant in 17 of the 36 lesions (47%; 95% confidence interval: 30.4%, 64.5%). Thirteen of the 17 lesions (76%; 95% confidence interval: 50.1%, 93.1%) were invasive malignancies. Twenty-two of the 36 abnormalities (61%) were either malignant or high-risk lesions (atypical ductal hyperplasia, lobular carcinoma in situ, atypical lobular hyperplasia). CONCLUSION DBT-guided needle localization is an accurate and feasible method with which to biopsy DBT-detected suspicious architectural distortions not visualized at mammography or sonography. The high risk of malignancy in abnormalities detected only with DBT (47%) confirms that routine biopsy is required for histologic analysis.

Breast-Density Legislation — Practical Considerations

A grassroots movement to inform women about their breast density has resulted in laws in 20 states mandating provision of that information. But the ability to detect breast cancer is affected by many factors, and evidence supporting supplemental screening is lacking.

Lesions of the Skin and Superficial Tissue at Breast MR Imaging

Although numerous studies have outlined the benefits of contrast material-enhanced magnetic resonance (MR) imaging for the detection of breast parenchymal findings, the assessment of lesions of the skin and superficial tissue at breast MR imaging has largely been overlooked. Such lesions, both benign and malignant, are commonly encountered at breast MR imaging, and their detection and diagnosis are often imperative. These lesions include superficial, locally extensive, inflammatory, and recurrent breast cancers; iatrogenic changes; sebaceous cysts; and less prevalent diseases such as granulomatous mastitis and angiosarcomas, among others. As MR imaging continues to be used with increasing frequency in both the screening and diagnostic settings, these lesions will be encountered more often; consequently, a better understanding of which lesions may be ignored and which require further evaluation will become increasingly important. Frequently, MR imaging alone may not clearly indicate the cause of lesions of the breast skin and superficial tissue. However, radiologists should thoroughly assess such lesions, taking into consideration the spectrum of possible causes. Mammography, ultrasonography, consultation with clinicians or dermatologists regarding physical examination findings, and, when necessary, correlation with pathologic findings in biopsy specimens may be used in conjunction with MR imaging to establish both the importance of these lesions and their definitive diagnoses.

To Do or Not to Do: Axillary Nodal Evaluation after ACOSOG Z0011 Trial

Methods of axillary evaluation in invasive breast cancer continue to evolve. The recent American College of Surgeons Oncology Group Z0011 Trial is a prospective, randomized, multicenter trial that compared the survival and locoregional recurrence rates after complete axillary lymph node dissection (ALND) versus sentinel node biopsy (SNB) alone in women with a positive sentinel node in an effort to avoid the complications associated with ALND. As the results of this trial are implemented clinically, affecting surgical management of axillary metastatic disease, radiologists may need to redefine their role in the preoperative assessment of the axilla. Before the Z0011 trial, breast imagers worked to identify axillary metastases preoperatively, allowing appropriate patients to proceed directly to ALND and avoiding the need for SNB. However, the Z0011 trial concluded that ALND may not be necessary in women with metastatic axillary disease who meet the trial criteria. In the Z0011 trial, after 6 years of median follow-up there was no difference in either locoregional recurrence or survival among the women who underwent SNB alone compared with those who underwent ALND, suggesting that ALND is unnecessary in a subset of women with a positive node at SNB. These results raise questions about how aggressively radiologists should pursue percutaneous sampling of axillary nodes, as some practitioners conclude that, in an otherwise eligible woman, positive results from imaging-guided percutaneous biopsy preclude a Z0011 trial-directed pathway. Debate about the best way to implement the results of the Z0011 trial into daily clinical practice exists. It is important for breast imagers to work closely with breast surgeons to provide the most appropriate treatment course for each patient.

Digital Breast Tomosynthesis in the Analysis of Fat-containing Lesions

Digital breast tomosynthesis (DBT) is rapidly emerging as an important clinical tool for both screening and diagnosis. DBT improves upon mammography by depicting breast tissue on a dynamic sequence of cross-sectional images reconstructed in planes corresponding to their mammographic planes of acquisition. DBT results in markedly reduced summation of overlapping tissue and depicts the margins of masses in far greater detail than mammography. Fat is commonly recognized in both benign and malignant breast masses at DBT, even when no fat is appreciated at mammography. In cases of encapsulated fat-containing masses, the increased detail at DBT often allows the radiologist to definitively classify a mass as benign (eg, lipoma, hamartoma, galactocele, lipid cyst) when mammographic findings alone are equivocal, thereby avoiding unnecessary biopsy or workup. However, when learning to read DBT images, many radiologists misinterpret this rule, mistaking the presence of any fat within a mass for an indication of benignity or an artifact and falsely concluding that an otherwise suspicious mass is not worrisome. If fat seen in breast masses at DBT is not appropriately analyzed, malignant breast masses may be incorrectly classified as probably or even definitely benign. With use of radiologic-pathologic correlation, the authors illustrate cases in which the presence of fat can help correctly classify a mass as benign, and pitfalls in which the presence or absence of fat within a mass is irrelevant and should not influence analysis.

Synthesized Digital Mammography Imaging

Synthesized mammography (SM) is a new imaging technique similar to digital mammography constructed from an acquired digital breast tomosynthesis (DBT) examination. SM allows for widespread screening using DBT, maintaining the benefits of DBT while decreasing the radiation of DBT by nearly half. This article reviews studies evaluating SM, most of which suggest that SM may be appropriate to use clinically to replace an actual acquired conventional 2-dimensional full-field digital mammogram (FFDM) when using DBT for breast cancer screening. These results should be interpreted with caution because there are inherent differences between SM and FFDM image quality and lesion visibility and larger, more robust studies still need to be performed.

Case records of the Massachusetts General Hospital. Case 8-2013. A 48-year-old woman with carcinoma in situ of the breast.

From the Department of Surgery, Memorial Sloan-Kettering Cancer Center, and the Department of Surgery, Weill Cornell Medical College — both in New York (M.M.); and the Departments of Surgery (J.M.W.), Radiology (P.E.F.), and Pathology ( J.H.E.), Massachusetts General Hospital; and the Departments of Surgery ( J.M.W.), Radiology (P.E.F.), and Pathology ( J.H.E.), Harvard Medical School — both in Boston.