Breast cancer axillary lymph node metastasis detection by a high-resolution dedicated breast camera: a comparative study with SPECT and pinhole SPECT

Comparison of 99mTc-MIBI scintigraphy, ultrasound, and mammography for the diagnosis of BI-RADS 4 category lesions

Background

We sought to determine the diagnostic efficacy of Breast-specific gamma imaging (BSGI) in Chinese women with BI-RADS 4 category lesions and to compare this efficacy to that of ultrasound/mammography.

Methods

We retrospectively analyzed data from 177 women that had undergone BSGI of BI-RADS 4 category lesions originally detected via ultrasound and/or mammography.

Results

Of these 177 cases, 117 (66.1%) were malignant lesions and 60 (33.9%) were benign. The sensitivity, specificity, positive predictive values, and negative predictive values of BSGI were 94.9% (111/117), 78.3% (47/60), 89.5% (111/124), and 88.7% (47/53), respectively. The specificity and positive predictive values for mammography were 48.3% (29/60) and 77.5% (107/138), while for ultrasound they were 53.3% (32/60) and 79.6% (109/137), respectively. The sensitivity and specificity of BSGI for the detection of lesions ≤1 cm in size were 90.9% (10/11) and 88.0% (22/25), respectively, while for breast lesions >1 cm in size these values were 94.3% (100/106) and 71.4% (25/35), respectively. In addition, BSGI sensitivity and specificity values for dense breast tissue were 94.0% (79/84) and 78.0% (39/50), respectively, whereas for non-dense breast tissue these vales were 97.0% (32/33) and 80.0% (8/10), respectively. The sensitivity of BSGI for invasive ductal carcinomas (IDC) and ductal carcinomas in situ (DCIS) was 98.9% (95/96) and 75.0% (9/12), respectively. The tumor to normal tissue ratio of BSGI for malignant lesions was significantly higher than for benign lesions (2.18 ± 1.17 vs 1.66 ± 0.40, t = 7.56, P<0.05).

Conclusions

These results indicate that BSGI is highly sensitive for the detection of such lesions, achieving good positive/negative predictive values. This suggests that for IDC in particular, BSGI is superior to ultrasound and mammography for the diagnosis of BI-RADS 4 category lesions, although this was less apparent for the diagnosis of DCIS lesions. BSGI exhibited excellent performance in dense breast tissue and for the detection of lesions ≤1 cm in size.

The role of molecular breast imaging in predicting complete tumor response to treatment and residual tumor extent following neoadjuvant therapy

The aim of the present study was to investigate the usefulness of molecular breast imaging (MBI) in predicting complete tumor response to treatment and residual tumor extent following neoadjuvant therapy. A consecutive series of 43 female patients with large or locally advanced primary breast cancer, scheduled for surgery following neoadjuvant therapy, was retrospectively reviewed. Prior to surgery, all patients underwent MBI using a high-resolution semiconductor-based device for image acquisition. MBI data were correlated with surgical histopathological findings. Spearman's correlation coefficient was calculated to assess differences in residual tumor size with MBI and histopathological examination. From the images obtained using MBI, 7 patients were negative for residual tumors with pathological complete response (specificity, 100%) and positive in 34/36 patients with residual disease (sensitivity, 94.4%), including 26/27 patients with unifocal and 8/9 patients with multicentric/multifocal tumors, 5 of which exhibited multiple microscopic foci scattered in a fibrotic area. Overall accuracy was 95.3% and the positive predictive value (PPV) and negative predictive value (NPV) were 100 and 77.8%, respectively. MBI was false-negative in one patient with a 2.5-cm invasive ductal carcinoma located close to the chest wall and in one patient with microscopic foci of epithelial carcinoma. In the patients with unifocal residual tumors, correlation of tumor size between MBI and histopathology was r=0.981 (P<0.0001); however, MBI overestimated the number of lesions in one of these cases. In the patients with multifocal/multicentric tumors, MBI adequately assessed residual tumor extent in 5/8 positive cases, overestimating the number of lesions in one case and underestimating tumor extent in 2 further cases with microscopic foci scattered in a fibrotic area. MBI proved to be a highly accurate diagnostic tool in predicting complete tumor response to neoadjuvant therapy and residual tumor extent, correlating with surgical histopathological findings in 86% of overall cases. A positive result was always associated with the presence of residual disease and MBI tumor size was strongly correlated with histopathological analysis mainly in unifocal residual tumors.

Clinical usefulness of breast-specific gamma imaging as an adjunct modality to mammography for diagnosis of breast cancer: a systemic review and meta-analysis

PURPOSE

The purpose of this study was to assess the diagnostic performance of breast-specific gamma imaging (BSGI) as an adjunct modality to mammography for detecting breast cancer.

METHODS

Comprehensive searches of MEDLINE (1984 to August 2012) and EMBASE (1994 to August 2012) were performed. A summary receiver operating characteristic curve (SROC) was constructed to summarize the overall test performance of BSGI. The sensitivities for detecting subcentimetre cancer and ductal carcinoma in situ (DCIS) were pooled. The potential of BSGI to complement mammography was also evaluated by identifying mammography-occult breast cancer.

RESULTS

Analysis of the studies revealed that the overall validity estimates of BSGI in detecting breast cancer were as follows: sensitivity 95 % (95 % CI 93-96 %), specificity 80 % (95 % CI 78-82 %), positive likelihood ratio 4.63 (95 % CI 3.13-6.85), negative likelihood ratio 0.08 (95 % CI 0.05-0.14), and diagnostic odds ratio 56.67 (95 % CI 26.68-120.34). The area under the SROC was 0.9552 and the Q* point was 0.8977. The pooled sensitivities for detecting subcentimetre cancer and DCIS were 84 % (95 % CI 80-88 %) and 88 % (95 % CI 81-92 %), respectively. Among patients with normal mammography, 4 % were diagnosed with breast cancer by BSGI, and among those with mammography suggestive of malignancy or new biopsy-proven breast cancer, 6 % were diagnosed with additional cancers in the breast by BSGI.

CONCLUSION

BSGI had a high diagnostic performance as an excellent adjunct modality to mammography for detecting breast cancer. The ability to identify subcentimetre cancer and DCIS was also high.