ABSTRACT
The study aimed to compare the metastatic pattern of breast cancer and the intermodality proportion of agreement between [18F]FDG-PET/CT and CE-CT. Women with metastatic breast cancer (MBC) were enrolled prospectively and underwent a combined [18F]FDG-PET/CT and CE-CT scan to diagnose MBC. Experienced nuclear medicine and radiology physicians evaluated the scans blinded to the opposite scan results. Descriptive statistics were applied, and the intermodality proportion of agreement was used to compare [18F]FDG-PET/CT and CE-CT. In total, 76 women with verified MBC were enrolled in the study. The reported number of site-specific metastases for [18F]FDG-PET/CT vs. CE-CT was 53 (69.7%) vs. 44 (57.9%) for bone lesions, 31 (40.8%) vs. 43 (56.6%) for lung lesions, and 16 (21.1%) vs. 23 (30.3%) for liver lesions, respectively. The proportion of agreement between imaging modalities was 76.3% (95% CI 65.2-85.3) for bone lesions; 82.9% (95% CI 72.5-90.6) for liver lesions; 57.9% (95% CI 46.0-69.1) for lung lesions; and 59.2% (95% CI 47.3-70.4) for lymph nodes. In conclusion, bone and distant lymph node metastases were reported more often by [18F]FDG-PET/CT than CE-CT, while liver and lung metastases were reported more often by CE-CT than [18F]FDG-PET/CT. Agreement between scans was highest for bone and liver lesions and lowest for lymph node metastases.
ABSTRACT
BACKGROUND: [18F]-fluorodeoxyglucose-positron emission tomography/computed tomography ([18F]FDG-PET/CT) has been implemented sporadically in hospital settings as the standard of care examination for recurrent breast cancer. We aimed to explore the clinical impact of implementing [18F]FDG-PET/CT for patients with clinically suspected recurrent breast cancer and validate the diagnostic accuracy. METHODS: Women with suspected distant recurrent breast cancer were prospectively enrolled in the study between September 2017 and August 2019. [18F]FDG-PET/CT was performed, and the appearance of incidental benign and malignant findings was registered. Additional examinations, complications, and the final diagnosis were registered to reflect the clinical consequence of such findings. The diagnostic accuracy of [18F]FDG-PET/CT as a stand-alone examination was analyzed. Biopsy and follow-up were used as a reference standard. RESULTS: [18F]FDG-PET/CT reported breast cancer metastases in 72 of 225 women (32.0%), and metastases were verified by biopsy in 52 (52/225, 23.1%). Prior probability and posterior probability of a positive test for suspected metastatic cancer and incidental malignancies were 27%/85% and 4%/20%, respectively. Suspected malignant incidental findings were reported in 46 patients (46/225, 20.4%), leading to further examinations and final detection of nine synchronous cancers (9/225, 4.0%). These cancers originated from the lung, thyroid, skin, pancreas, peritoneum, breast, kidney, one was malignant melanoma, and one was hematological cancer. False-positive incidental malignant findings were examined in 37/225 patients (16.4%), mainly in the colon (n = 12) and thyroid gland (n = 12). Ten incidental findings suspicious for benign disease were suggested by [18F]FDG-PET/CT, and further examinations resulted in the detection of three benign conditions requiring treatment. Sensitivity, specificity, and AUC-ROC for diagnosing distant metastases were 1.00 (0.93-1.0), 0.88 (0.82-0.92), and 0.98 (95% CI 0.97-0.99), respectively. CONCLUSION: [18F]FDG-PET/CT provided a high posterior probability of positive test, and a negative test was able to rule out distant metastases in women with clinically suspected recurrent breast cancer. One-fifth of patients examined for incidental findings detected on [18F]FDG-PET/CT were diagnosed with clinically relevant conditions. Further examinations of false-positive incidental findings in one of six women should be weighed against the high accuracy for diagnosing metastatic breast cancer. Trial registration Clinical.Trials.gov. NCT03358589. Registered 30 November 2017-Retrospectively registered, http://www.ClinicalTrials.gov.
ABSTRACT
PURPOSE: To investigate the clinical impact of FDG-PET/CT for staging and treatment planning in high-risk primary breast cancer. METHODS: Women with high-risk primary breast cancer were enrolled between September 2017 and August 2019 at Odense University Hospital, Denmark. Conventional mammography with/without MRI was performed before staging by FDG-PET/CT. We studied the accuracy of FDG-PET/CT for the detection of distant metastases, the effect on the change of treatment, and the prevalence of incidental findings. Biopsy and follow-up were used as a reference standard for the accuracy analysis. RESULTS: Of 103 women, 24 (23%) were diagnosed with distant metastases by FDG-PET/CT. Among these, breast surgery was omitted in 18 and could have been spared in six. Another sixteen (16%) patients were upstaged to more advanced loco-regional disease, leading to more extensive radiotherapy. Sensitivity and specificity for diagnosing distant metastases were 1.00 (95% confidence interval: 0.86-1.00) and 0.95 (0.88-0.99), respectively. Twenty-nine incidental findings were detected in 24 women (23%), leading to further examinations in 22 and diagnosis of eight (8/22, 36%) synchronous diseases: cancer (n = 4), thyroiditis (n = 2), aorta aneurysm (n = 1), and meningioma (n = 1). CONCLUSIONS: FDG-PET/CT had a substantial impact on staging and change of treatment in women with high-risk primary breast cancer, and further examination of incidental findings was considered clinically relevant. Our findings suggest that FDG-PET/CT should be considered for primary staging in high-risk primary breast cancer to improve treatment planning.
