Inter- and intra-observer variability of qualitative visual breast-composition assessment in mammography among Japanese physicians: a first multi-institutional observer performance study in Japan.

BACKGROUND: Visual assessment of mammographic breast composition remains the most common worldwide, although subjective variability limits its reproducibility. This study aimed to investigate the inter- and intra-observer variability in qualitative visual assessment of mammographic breast composition through a multi-institutional observer performance study for the first time in Japan. METHODS: This study enrolled 10 Japanese physicians from five different institutions. They used the new Japanese breast-composition classification system 4th edition to subjectively evaluate the breast composition in 200 pairs of right and left normal mediolateral oblique mammograms (number determined using precise sample size calculations) twice, with a 1-month interval (median patient age: 59 years [range 40-69 years]). The primary endpoint of this study was the inter-observer variability using kappa (κ) value. RESULTS: Inter-observer variability for the four and two classes of breast-composition assessment revealed moderate agreement (Fleiss' κ: first and second reading = 0.553 and 0.587, respectively) and substantial agreement (Fleiss' κ: first and second reading = 0.689 and 0.70, respectively). Intra-observer variability for the four and two classes of breast-composition assessment demonstrated substantial agreement (Cohen's κ, median = 0.758) and almost perfect agreement (Cohen's κ, median = 0.813). Assessments of consensus between the 10 physicians and the automated software Volpara® revealed slight agreement (Cohen's κ; first and second reading: 0.104 and 0.075, respectively). CONCLUSIONS: Qualitative visual assessment of mammographic breast composition using the new Japanese classification revealed excellent intra-observer reproducibility. However, persistent inter-observer variability, presenting a challenge in establishing it as the gold standard in Japan.

Comparative study of the usefulness of adjunctive tomosynthesis in breast cancer screening by mammography and ultrasound in Japan.

INTRODUCTION: There are few studies have conducted digital breast tomosynthesis (DBT) in addition to digital mammography (2DDM) and ultrasound (US) for screening. The purpose of this study is to determine the possibility of synergistic effects of DBT and US screening for Japanese. METHODS: 5023 examinations of the opportunistic screening using 2DDM and US (2D group: 2581) or 2DDM and US plus DBT (3 group: 2442) were performed at our facility from May 1, 2017 to March 31, 2019. This study was not RCT, and the backgrounds of the two groups were different. RESULTS: The recall rate was 3.1% in the 2D group and 2.6% for the 3D group (p = 0.27). The number of detected cancer cases was 6 (0.23%) in the 2D group and 12 (0.49%) in the 3D group (p = 0.16). The positive predictive value (PPV) was 7.4% for the 2D group and 19.0% for the 3D group (p = 0.045). There was one invasive ductal carcinoma case which had no findings in 2DDM and US, but had a slight distortion in the images of DBT. CONCLUSION: We examined and reported whether DBT was useful for breast cancer screening combined with mammography and US. Compared to the 2D group, the 3D group showed better results of PPV with significant difference. However, due to the non-randomized design and difference between the two groups, the results should be interpreted in caution. Adding DBT in 2DDM and US screening would be acceptable only if the benefits and disadvantages are explained to the women undergoing the screening.

Digital Breast Tomosynthesis Complements Two-Dimensional Synthetic Mammography for Secondary Examination of Breast Cancer.

OBJECTIVE: To compare the performance of two-dimensional synthetic mammography (SM) combined with digital breast tomosynthesis (DBT) (SM/DBT) and full-field digital mammography (FFDM) including women with DBT (FFDM/DBT) undergoing secondary examination for breast cancer. MATERIAL AND METHODS: Out of 186 breasts, including 52 with breast cancers; FFDM/DBT and SM/DBT findings were interpreted by four expert clinicians. Radiation doses of FFDM, SM/DBT, and FFDM/DBT were determined. Inter-rater reliabilities were analyzed between readers and between FFDM/DBT and SM/DBT by Cohen's Kappa coefficients. Diagnostic accuracy was compared between SM/DBT and FFDM/DBT by Fisher's exact tests. Two representative cancer cases were examined for differences in the interpretation between FFDM and SM. RESULTS: A higher radiation dose was required in FFDM/DBT than in SM/DBT (median: 1.50 mGy vs. 2.95 mGy). Inter-rater reliabilities were similar between both readers and modalities. Both sensitivity and specificity were equivalent in FFDM/DBT and SM/DBT (p = 0.874-1.00). Compared with FFDM, SM did not clearly show abnormalities with subtle margins in the two representative cancer cases. CONCLUSION: SM/DBT had a similar performance to FFDM/DBT in detecting breast abnormalities but requires less radiation. DBT complements SM to improve accuracy to a level equivalent to that of FFDM. Taken together, SM/DBT may be a good substitute for FFDM/DBT for the secondary examination of breast cancer.

Utility of B-Mode, Color Doppler and Elastography in the Diagnosis of Breast Cancer: Results of the CD-CONFIRM Multicenter Study of 1351 Breast Solid Masses.

The usefulness of color Doppler ultrasound (CD) in distinguishing between benign and malignant breast lesions remains controversial. Our prior study, the Japan Association of Breast and Thyroid Sonology (JABTS) BC-04 study (malignant: 839, benign: 569), found CD was useful in breast cancer diagnosis, and we developed CD diagnostic criteria. The first aim of the current study (the CD-CONFIRM study) was to evaluate the usefulness of the CD diagnostic criteria. The second aim was to evaluate the relationship between CD and elastography. We evaluated ultrasound images of breast masses from 13 institutions (malignant: 639, benign: 712). While the sensitivity of B-mode alone was very high and was not significantly improved with CD, the specificity was significantly improved with CD (61.2%-69.2%, p < 0.0001). Furthermore, the specificity of the combination of B-mode and CD improved significantly with the addition of elastography (72.8%-79.0%, p < 0.0001). This study found that the CD criteria are useful, and CD and elastography are independent.

B-mode ultrasound diagnostic flowchart for solid breast masses: JABTS BC-01 study.

PURPOSE: Breast ultrasound has been widely used as an essential examination for diagnosing breast cancer. However, standardized diagnostic criteria are as yet lacking. This study aimed to develop a simple diagnostic flowchart for beginners learning breast ultrasonography. The diagnostic flowchart was developed based on the recall criteria widely used in Japan. METHODS: We conducted a multicenter study to examine recall criteria usefulness in the diagnostic phase of breast disease. Women with ultrasound-visible breast masses who underwent B-mode breast ultrasound examination were recruited from 22 hospitals in Japan between September 2009 and January 2010. B-mode images were evaluated by members of the centralized image interpretation committee. We developed the new diagnostic flowchart based on the results. The usefulness of the diagnostic flowchart was assessed by employing datasets from the current study and another study which we conducted (BC-04 study). RESULTS: We evaluated 1045 solid masses (malignant: 495, benign: 550). Multivariate analysis showed that shape, margin, echogenic halo, interruption of the mammary gland interface, and depth width ratio were significant findings for distinguishing between benign and malignant masses. We modified the recall criteria and developed our novel diagnostic flowchart using these findings. The sensitivity and specificity of the new flowchart (current study: 0.97, 0.45; BC-04 study dataset: 0.95, 0.45) were similar to those of experts (current study: 0.96, 0.54; BC-04 study dataset: 0.98, 0.38). CONCLUSION: We developed a simple diagnostic flowchart for breast ultrasound. This flowchart is anticipated to be applicable to educating beginners learning breast ultrasound.

Breast cancer screening using digital breast tomosynthesis compared to digital mammography alone for Japanese women.

BACKGROUND: The purpose of this study is to confirm the position of DBT in breast cancer screening in Japan, to assess cancer detection rates, recall rates, positive predictive value (PPV), and to evaluate the type of mammographic findings of cancer with the use of digital mammography alone (2DDM) and combined with digital breast tomosynthesis (DBT). METHODS: 11,894 examinations of the opportunistic breast cancer screening using only 2DDM and 2DDM plus DBT were performed from May 1, 2017 to March 31, 2019. The 11,894 women [3535 women who received DBT in addition to 2DDM (3D group) and 8359 who received 2DDM only (2D group)] participated in this study. The study was approved by the Institute's Ethics Committee and all participants provided written informed consent. RESULTS: The recall rate was 2.6% for the 3D group and 3.6% for the 2D group (p < 0.01). The cancer detection rate was 0.17% in both 3D and 2D groups (p = 0.978). The positive predictive value (PPV) was 6.5% for the 3D group and 4.7% for the 2D group (p = 0.484). The cause of the decrease in recall rate was due to a decrease in the finding of focal asymmetric density (FAD). CONCLUSION: The recall rate was improved by using DBT for breast cancer screening in Japanese women. Cancer detection rates were exactly the same in DBT and 2DDM groups, so only DBT non-inferiority could be verified. We have verified that breast cancer screening combined with DBT is useful even for Japanese women to reduce unnecessary further examination.

Characteristics of ultrasonographic images of ductal carcinoma in situ with abnormalities of the ducts.

PURPOSE: Although the number of ductal carcinoma in situ (DCIS) cases has increased with the spread of breast cancer screening in Japan, there are very few reports that summarize ultrasound image features of DCIS. The Japan Association of Breast and Thyroid Sonology (JABTS) investigated the incidence of DCIS with masses and non-mass abnormalities and the characteristics of US images in a retrospective, multicenter, observational study (JABTS BC-02 study). The purpose of this report is to clarify the proportion of DCIS with abnormalities of the ducts with each ultrasound finding and the characteristics of US images. METHODS: The JABTS BC-02 study population was comprised of patients who were examined by ultrasonography, underwent surgery, and were histopathologically diagnosed with DCIS at each study site between January 2008 and December 2012. The US images of DCIS and pathology and clinical information were retrospectively collected from 16 institutions in Japan. The US images were evaluated by 22 experts on the Central Image Interpretation Committee of JABTS. RESULTS: Abnormalities of the ducts were noted in 78 (10.5%) of 705 US images of DCIS. Of the 78 cases, the distribution of abnormalities of the ducts was focal or segmental. The second characteristic was the presence of internal echoes in dilated ducts. All cases were accompanied by intraductal solid echoes, and 40 cases (51.3%) were accompanied by echogenic foci. In addition, intraductal solid echoes were continuous or multiple in 72 cases (92.4%), and the shape of the solid echoes was broad-based and/or irregular in 62 cases (79.5%). CONCLUSION: DCIS cases with duct abnormalities on ultrasound were investigated in this study. The important characteristics were as follows: (1) the distribution of ductal dilatation was focal or segmental, (2) solid parts were present in the dilated ducts, (3) the distribution of internal echoes was continuous or multiple, (4) the shape of solid echoes was broad-based and/or irregular, and (5) internal echoes were sometimes accompanied by echogenic foci. Accurate evaluation of these findings may be useful for diagnosing DCIS. Although the duct abnormalities are included in "ASSOCIATED FEATURES" in ACR BI-RADS ATLAS (USA), we emphasize that this concept is very important for understanding US characteristics of DCIS.

Multicenter Prospective Study of Color Doppler Ultrasound for Breast Masses: Utility of Our Color Doppler Method.

The use of color Doppler ultrasound (CD) for distinguishing between benign and malignant breast lesions remains controversial. This study (JABTS BC-04 study) was aimed at confirming the usefulness of our CD diagnostic criteria. We evaluated ultrasound images of 1408 solid breast masses from 16 institutions in Japan (malignant: 839, benign: 569). Multivariate analysis indicated that vascularity (amount of blood flow), vascular flow pattern ("surrounding marginal flow" or "penetrating flow") and the incident angle of penetrating flow were significant findings for distinguishing between benign and malignant lesions. However, the sensitivity and specificity of B-mode alone did not improve significantly with CD addition (97.6% → 97.9%, 38.3% → 41.5%, respectively). We explored the causes of these negative results and found that age should have been considered when evaluating vascularity. Simulation experiments suggested that specificity is significantly improved when age is taken into consideration (38.3% → 46.0%, p < 0.001) and we thereby improved our diagnostic criteria.

Verification of recall criteria for masses detected on ultrasound breast cancer screening.

PURPOSE: Mammography is the only modality for breast cancer screening demonstrated to reduce the mortality rate. However, ultrasonographic screening is already being widely performed as opportunistic screening in Japan. The recall criteria for masses are very important as quality controls. The purpose of this study was to verify these criteria at multiple institutions. METHODS: Screening was performed by five institutions in various regions in Japan. The total number of cases screened at all five institutions was 10,519. RESULTS: The findings that could be concluded to be benign were a cystic pattern and three features of a solid pattern. The cystic pattern was noted in 6512 cases, typical fibroadenoma in 1483 cases, and typical complicated cyst in 70 cases. Only three of these 8065 cases were cancers, so the negative predictive value was 99.9%. The solid pattern with obvious malignant features, i.e., masses with an echogenic halo and/or interruption of the interface and masses with multiple echogenic foci, were noted in 33 cases. Twenty of the 33 cases were malignancy, resulting in a positive predictive value of 66.7%. CONCLUSION: Although some parts of the criteria should be considered further for verification and revision, the current recall criteria are mostly valid.

Ultrasound Image Classification of Ductal Carcinoma In Situ (DCIS) of the Breast: Analysis of 705 DCIS Lesions.

The Japan Association of Breast and Thyroid Sonology (JABTS) proposed, in 2003, a conceptual classification system for non-mass abnormalities to be applied in addition to the conventional concept of masses, to facilitate detecting ductal carcinoma in situ (DCIS) lesions. The aim of this study was to confirm the utility of this system and to clarify the distribution of these findings in DCIS lesions. Data on 705 surgically treated DCIS lesions from 16 institutions in Japan were retrospectively reviewed. All 705 DCIS lesions could be classified according to the JABTS classification system. The most frequent findings were hypo-echoic areas in the mammary gland (48.6%), followed by solid masses (28.0%) and duct abnormalities (10.2%) or mixed masses (8.1%). Distortion (1.3%), clustered microcysts (1.4%) and echogenic foci without a hypo-echoic area (2.5%) were uncommon. These results suggest that the concept of non-mass abnormalities is useful in detecting DCIS lesions.

Factors affecting successful palliative surgery for malignant bowel obstruction due to peritoneal dissemination from colorectal cancer.

BACKGROUND: Nonresectable colorectal cancer often causes malignant intestinal obstruction due to peritoneal dissemination. However, no previous report has specifically investigated which patients, with peritoneal dissemination from colorectal cancer, would actually benefit from palliative surgery. This study defines the selection criteria for patients who are likely to benefit from palliative surgery. METHODS: Twenty-one patients underwent palliative surgery for malignant bowel obstruction due to peritoneal dissemination from colorectal cancer. In all cases, the advanced and nonresectable nature of the tumor was confirmed at laparotomy. Clinical factors such as age, gender, serum level of carcinoembryonic antigen, amount of ascites, location of the primary cancer, surgical procedure, and postoperative chemotherapy were analyzed for prognostic significance in symptom-free and overall survival using the Kaplan-Meier product limit method and the log-rank test. RESULTS: All the postoperative courses were uneventful. Obstruction recurred after a median symptom-free interval of 61 days in the group with less than 100 ml of ascites, whereas it recurred after 9 days in the group with more than 100 ml of ascites. Symptom-free survival rates in patients who manifested ascites were significantly lower than in those without ascites (P = 0.0321, log-rank method). The symptom-free and overall survival rates in patients who underwent postoperative chemotherapy were significantly higher (P = 0.0225 and 0.0003). CONCLUSIONS: Palliative surgery can be performed effectively for patients without ascites. For patients who do not meet this criterion, a non-surgical procedure may be preferable.