Consensus Meeting of Breast Imaging: BI-RADS® and Beyond

Organizers of medical educational courses are often confronted with questions that are clinically relevant yet trespassing the frontiers of scientifically proven, evidence-based medicine at the point of care. Therefore, since 2007 organizers of breast teaching courses in German language met biannually to find a consensus in clinically relevant questions that have not been definitely answered by science. The questions were prepared during the 3 months before the meeting according to a structured process and finally agreed upon the day before the consensus meeting. At the consensus meeting, the open questions concerning 2D/3D mammography, breast ultrasound, MR mammography, interventions as well as risk-based imaging of the breast were presented first for electronic anonymized voting, and then the results of the audience were separately displayed from the expert votes. Thereafter, an introductory statement of the moderator was followed by pros/cons of two experts, and subsequently the final voting was performed. With ≥75% of votes of the expert panel, an answer qualified as a consensus statement. Seventeen consensus statements were gained, addressing for instance the use of 2D/3D mammography, breast ultrasound in screening, MR mammography in women with intermediate breast cancer risk, markers for localization of pathologic axillary lymph nodes, and standards in risk-based imaging of the breast. After the evaluation, comments from the experts on each field were gathered supplementarily. Methodology, transparency, and soundness of statements achieve a unique yield for all course organizers and provide solid pathways for decision making in breast imaging.

Malignancy rates of B3-lesions in breast magnetic resonance imaging - do all lesions have to be excised?

BACKGROUND

Approximately 10% of all MRI-guided vacuum-assisted breast biopsies (MR-VAB) are histologically classified as B3 lesions. In most of these cases surgical excision is recommended. The aim of our study was to evaluate the malignancy rates of different B3 lesions which are visible on MRI to allow a lesion-adapted recommendation of further procedure.

METHODS

Retrospective analysis of 572 consecutive MR-VAB was performed. Inclusion criteria were a representative (=successful) MR-VAB, histologic diagnosis of a B3 lesion and either the existence of a definite histology after surgical excision or proof of stability or regression of the lesion on follow-up MRI. Malignancy rates were evaluated for different histologies of B3 lesions. Lesion size and lesion morphology (mass/non-mass enhancement) on MRI were correlated with malignancy.

RESULTS

Of all MR-VAB 43 lesions fulfilled the inclusion criteria. The malignancy rate of those B3 lesions was 23.3% (10/43). The highest malignancy rate was found in atypical ductal hyperplasia (ADH) lesions (50.0%; 4/8), 33.3% (2/6) in flat epithelial atypia (FEA), 28.6% (2/7) in lobular intraepithelial neoplasia (LIN) and 12.5% (2/16) in papillary lesions (PL). All 6 complex sclerosing lesions were benign. Mass findings were significantly more frequently malignant (31.3%, 10/32; p < 0.05) than non-mass findings (0/11). Small lesions measuring 5-10 mm were most often malignant (35.0%; 7/20). All large lesions (> 20 mm) were not malignant (0/10). Intermediate sized lesions (11-20 mm) turned out to be malignant in 23.1% (3/13).

CONCLUSIONS

The malignancy rate of B3 lesions which were diagnosed after MR-VAB was 23.3%. ADH, FEA and LIN showed considerable malignancy rates (50%, 33% and 29%) and should therefore undergo surgical excision. None of the cases, which were diagnosed as radial scars, non-mass enhancement or larger lesions (> 20 mm) were malignant. Here, a follow-up MRI seems to be advisable to avoid unnecessary operations.

TRIAL REGISTRATION

Retrospective study design, waived by the IRB.

Preoperative breast MR Imaging in patients with primary breast cancer has the potential to decrease the rate of repeated surgeries

PURPOSE

The impact of preoperative MRI on re-excisions and mastectomy rate is discussed controversially in the literature. Aim of this study was to evaluate the effect of preoperative breast MRI on the surgical procedure and rate of repeated surgeries.

MATERIAL AND METHODS

A total of 991 consecutive patients in the years 2009 and 2010 with 1036 primary breast cancers were retrospectively analyzed. Sixty percent (599 patients with 626 cancers) received preoperative breast MRI. Planned surgical procedures before and after MRI and numbers of repeated surgeries in patients with (MR+ ) and without preoperative MRI (MR-) were compared.

RESULTS

The result of preoperative MRI changed the surgical procedure in 25% (157/626) of the cases. In 81% (127/157), MRI was beneficial for the patients, as otherwise occult carcinomas were removed (n=122) or further biopsy could be prevented (n=5). Mastectomy rates did not differ between MR+ and MR- group (39% vs. 39%). On multiple regression analysis, the MR+ group had a lower chance for repeated surgery (p<0.05).

CONCLUSION

Preoperative MRI could lower the chance for repeated surgery in patients with primary breast cancer. The rate of mastectomy did not differ between patients undergoing preoperative MRI and those who did not.

Vacuum-assisted breast biopsy with 7-gauge, 8-gauge, 9-gauge, 10-gauge, and 11-gauge needles: how many specimens are necessary?

BACKGROUND

Published national and international guidelines and consensus meetings on the use of vacuum-assisted biopsy (VAB) give different recommendations regarding the required numbers of tissue specimens depending on needle size and imaging method.

PURPOSE

To evaluate the weights of specimens obtained with different VAB needles to facilitate the translation of the required number of specimens between different breast biopsy systems and needle sizes, respectively.

MATERIAL AND METHODS

Five different VAB systems and seven different needle sizes were used: Mammotome® (11-gauge (G), 8-G), Vacora® (10-G), ATEC Sapphire™ (9-G), 8-G Mammotome® Revolve™, and EnCor Enspire® (10-G, 7-G). We took 24 (11-G) or 20 (7-10-G) tissue cores from a turkey breast phantom. The mean weight of a single tissue core was calculated for each needle size. A matrix, which allows the translation of the required number of tissue cores for different needle sizes, was generated. Results were compared to the true cumulative tissue weights of consecutively harvested tissue cores.

RESULTS

The mean tissue weights obtained with the 11-G / 10-G Vacora® / 10-G Enspire® / 9-G / 8-G Original / 8-G Revolve™ / 7-G needles were 0.084 g / 0.142 g / 0.221 g / 0.121 g / 0.192 g / 0.334 g / 0.363 g, respectively. The calculated required numbers of VAB tissue cores for each needle size build the matrix. For example, the minimum calculated number of required cores according to the current German S3 guideline is 20 / 12 / 8 / 14 / 9 / 5 / 5 for needles of 11-G / 10-G Vacora® / 10-G Enspire® / 9-G / 8-G Original / 8-G Revolve™ / 7-G size. These numbers agree with the true cumulative tissue weights.

CONCLUSION

The presented matrix facilitates the translation of the required number of VAB specimens between different needle sizes and thereby eases the implementation of current guidelines and consensus recommendations into clinical practice.

BI-RADS® 3 lesions at contrast-enhanced breast MRI: is an initial short-interval follow-up necessary?

BACKGROUND

Magnetic resonance imaging (MRI) BI-RADS® 3 lesions should have a very high probability of being benign. To prove benignity most institutions do follow-up MRI.

PURPOSE

To evaluate the necessity of initial short-interval follow-up after 6 months as it is suggested for mammographic BI-RADS®3 lesions.

MATERIAL AND METHODS

We analyzed 163 consecutive MRI-BI-RADS® 3 lesions on follow-up MRI: 75 masses (46%), 67 foci (41.1%), and 21 (12.9%) non-mass-like enhancing lesions (NMLE).

RESULTS

During MRI follow-up (mean time, 563 days) 20% of the lesions disappeared, 23% decreased, 52% did not change, and 4.9% showed increase. All increasing lesions were biopsied (5 benign, 2 ductal carcinoma in situ, 1 invasive carcinoma). The rate of malignancy was 1.8%. All malignant lesions (1 mass, 1 focus, 1 NMLE) showed increase at initial follow-up after a mean interval of 190 days.

CONCLUSION

In this study the malignancy rate of MRI-BI-RADS® 3 lesions corresponded to mammographic BI-RADS® 3 lesions. Initial short-interval MRI should be suggested to identify malignant MRI-BI-RADS® 3 lesions.

Management of breast lesions detectable only on MRI

Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline "Diagnosis, Therapy, and Follow-Up of Breast Cancer" as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented.

KEY POINTS

▶ Up to 57 % of lesions originally visible only on MRI can be sonographically correlated and biopsied. ▶ MRI-guided intervention is necessary for the clarification of BI-RADS® 4 and 5 lesions detectable only on MRI ▶ MRI-guided vacuum-assisted breast biopsy should be preferentially used ▶ MRI-guided localization and surgical excision should be used if MRI-guided vacuum-assisted biopsy is not possible ▶ If BI-RADS® 4 and 5 findings visible only on MRI are not detectable on interventional MRI, a follow-up MRI should be performed within six months.

Breast MRI of pure ductal carcinoma in situ: sensitivity of diagnosis and influence of lesion characteristics

OBJECTIVES

The purpose of the study was to evaluate the sensitivity of breast MRI in the detection of pure DCIS and to analyze the influence of lesion type and nuclear grade.

METHODS

58 consecutive patients with pathologically proven pure DCIS and preoperatively performed breast MRI were retrospectively reviewed and analyzed. Sensitivities in the detection of DCIS were calculated for MRI and mammography (Mx). Influence of MRI lesion type and nuclear grading on DCIS diagnosis was evaluated.

RESULTS

MRI detected pure DCIS with a sensitivity of 79.3%. The sensitivity of Mx was lower (69%), but the difference was not statistically significant (p=0.345). 46.2% of the DCIS presented as enhancing mass and 53.8% as non-mass-like enhancement (NMLE). None of the masses but 21.4% (n=6) of the NMLE were underestimated as probably benign (BI-RADS 3). MRI measured lesion sizes showed a moderate correlation (r=0.74) with histopathologically measured lesion sizes. MRI detection rate of DCIS decreased significantly (p=0.0458) with increasing nuclear grade. Calculated sensitivities were 100% for low-grade DCIS, 84.6% for intermediate-grade DCIS, and 66.7% for high-grade DCIS.

CONCLUSIONS

In this study MRI could detect pure DCIS more sensitively than Mx. Despite of missing statistically significance preoperative MRI seems to be helpful in patients with DCIS who are eligible for breast conservation. This applies in particular to patients with non-high-grade DCIS because those were significantly more often positive on MRI and significantly more often negative on Mx. Misinterpretation occurs especially in cases of NMLE and high-grade DCIS and therefore a correlation with Mx is also recommended.