Benefits and harms of implementing [18F]FDG-PET/CT for diagnosing recurrent breast cancer: a prospective clinical study.

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.

FDG-PET/CT in high-risk primary breast cancer-a prospective study of stage migration and clinical impact.

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.

Lack of nationwide Danish guidelines on mammography before non-oncological breast surgery.

INTRODUCTION: Non-oncological breast surgery like breast reduction and mastopexy are often performed in younger patients, i.e. in women who have not yet had mammography. Breast cancer is, however, a very frequent disease that is increasingly prevalent in women below 50 years of age. Occult breast cancer may not be recognised before breast surgery, which may result in several disadvantages for the women. Therefore, detecting a breast cancer before a woman undergoes non-oncological breast surgery is of paramount importance. METHODS: All public plastic surgery and breast surgery departments and all private clinics or hospitals providing plastic surgery were asked two questions: 1) When do you recommend a mammography prior to non-oncological breast surgery? 2) How old must a mammogram be before it needs to be repeated? RESULTS: Answers were received from all plastic surgery and breast surgery departments, and all but three of the private clinics and hospitals. Overall, information was obtained from 95.5% of the respondents (n = 63). CONCLUSION: Currently, there are no Danish guidelines on mammography before non-oncological breast surgery. A national guideline could recommend a preoperative mammogram from the age of 40 years stipulating that the mammogram should have been made within the past 12 months; however, the final recommendation should be prepared by a multidisciplinary working group counting experts from plastic surgery, breast surgery, pathology and radiology. FUNDING: not relevant. TRIAL REGISTRATION: not relevant.