Preoperative PET/CT in early-stage breast cancer

18FDG PET-CT for diagnosis of distant metastases in breast cancer patients. A meta-analysis

BACKGROUND

We performed a meta-analysis to evaluate the value of (18)FDG PET-CT for diagnosis of distant metastases in breast cancer patients.

METHODS

Studies about PET-CT were systematically searched in the MEDLINE and EMBASE databases. We calculated sensitivities, specificities, likelihood ratios, and constructed summary receiver operating characteristic curves for PET-CT. We also compared the performance of PET-CT with that of conventional imaging by analyzing studies that had also used conventional imaging on the same patients.

RESULTS

Across 8 PET-CT studies (748 patients), sensitivity and specificity of PET-CT were 0.96 (95% confidence interval [CI] = 0.90-0.98) and 0.95 (95% CI = 0.92-0.97). Across 6 comparative studies (664 patients), sensitivity and specificity of PET-CT were 0.97 (95% CI = 0.84-0.99) and 0.95 (95% CI = 0.93-0.97), and of conventional imaging were 0.56 (95% CI = 0.38-0.74) and 0.91 (95% CI = 0.78-0.97), respectively.

CONCLUSIONS

Compared with conventional imaging, (18)FDG PET-CT has higher sensitivity for diagnosis of distant metastases in breast cancer patients.

The Effects of Preoperative (18)F-FDG PET/CT in Breast Cancer Patients in Comparison to the Conventional Imaging Study

PURPOSE

There have been recent studies of the (18)F-fluorodeoxyglucose positron emission tomography and computed tomography ((18)F-FDG PET/CT) in the staging, detection, and follow-up of the breast cancer occurrence and recurrence. There was controversy concerning the use of (18)F-FDG PET/CT for staging primary breast cancer. In this study, we investigated the potential effects of (18)F-FDG PET/CT in the initial assessment of patients with primary breast cancer.

METHODS

From January 2008 to December 2009, 154 consecutive biopsy-proven invasive breast cancer patients were enrolled in this study. Patients underwent conventional imaging studies including mammography, breast ultrasonography (USG), and magnetic resonance imaging for local assessment, and plain chest X-ray, liver USG, and bone scan to rule out distant metastasis. All 154 patients underwent (18)F-FDG PET/CT in the initial assessment.

RESULTS

(18)F-FDG PET/CT did not detect primary breast lesions in 16 patients with a sensitivity of 89.6% and detected only 5 multiple lesions (12.5%) out of 40 cases. Histologically confirmed axillary lymph node (LN) metastases were in 51 patients, and the sensitivity and specificity of (18)F-FDG PET/CT to detect metastatic axilla were 37.3% and 95.8%, respectively; whereas the corresponding estimates of USG were 41.2% and 93.7%, respectively. Eleven extra-axillary LN metastases were found in eight patients, and seven lesions were detected by (18)F-FDG PET/CT only. The sensitivity and specificity of (18)F-FDG PET/CT in detecting distant metastasis were 100% and 96.4%, respectively; whereas the sensitivity and specificity of the conventional imaging were 61.5% and 99.2%, respectively.

CONCLUSION

(18)F-FDG PET/CT cannot be recommended as a primary diagnostic procedure in breast cancer, but it has the potential to be used as an additional imaging tool for the detection of axillary metastasis, distant metastasis, and extra-axillary LN metastasis. (18)F-FDG PET/CT cannot solely replace the conventional diagnostic procedure in primary breast cancer. The best approach may be the combination of different imaging modalities.

The current status of positron emission mammography in breast cancer diagnosis

Mammography is currently the standard breast cancer screening procedure, even though it is constrained by low specificity in the detection of malignancy and low sensitivity in women with dense breast tissue. Modern imaging modalities, such as magnetic resonance imaging (MRI), have been developed in an effort to replace or complement mammography, because the early detection of breast cancer is critical for efficient treatment and long-term survival of patients. Nuclear medicine imaging technology has been introduced in the field of oncology with the development of positron emission tomography (PET), positron emission tomography/computed tomography (PET/CT) and, ultimately, positron emission mammography (PEM). PET offers the advantage of precise diagnosis, by measuring metabolism with the use of a radiotracer and identifying changes at the cellular level. PET/CT imaging allows for a more accurate assessment by merging the anatomic localization to the functional image. However, both techniques have not yet been established as diagnostic tools in early breast cancer detection, primarily because of low sensitivity, especially for sub-centimeter and low-grade tumors. PEM, a breast-specific device with increased spatial resolution, has been developed in order to overcome these limitations. It has demonstrated higher detectability than PET/CT and comparable or better sensitivity than MRI. The ability to target the lesions visible in PEM with PEM-guided breast biopsy systems adds to its usability in the early diagnosis of breast cancer. The results from recent studies summarized in this review indicate that PEM may prove to be a useful first-line diagnostic tool, although further evaluation and improvement are required.