Comparison of 18F-Fluorodeoxyglucose positron emission tomography/computed tomography and conventional imaging for locally advanced breast cancer staging: A prospective study from a tertiary hospital cancer centre in the Western Cape

Background: Breast cancer is the second most common cancer in adults and the most frequent cancer diagnosed in women. In South Africa, breast cancer accounts for 38.5% of cancers diagnosed in women. Since the presence, extent and location of distant metastases is one important prognostic factor in locally advanced breast cancer (LABC), accurate staging at diagnosis is crucial to ensure that patients receive the appropriate treatment. Increasing evidence shows that the use of 18 F-Fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) for disease staging of LABC may improve diagnostic sensitivity. Aim: The aim of this study was to prospectively assess the difference in diagnostic accuracy between whole-body PET/PET-CT and conventional imaging (CI) for staging LABC. Setting: The breast cancer outpatient clinic at Groote Schuur Hospital in Cape Town, South Africa. Methods: A total of 42 participants with clinical stage III and a select few stage II breast cancer underwent both 18 F-FDG PET/CT and CI. Results: The 18 F-FDG PET/CT found significantly more ( p = 0.0077) distant metastatic sites than CI (36% vs. 21%). The 18 F-FDG PET/CT upstaged 9 (21.4%) of patients from clinical stage IIIa to stage IIIc, and changed in management of 54% of patients. Thirty-eight per cent of the patients had their clinical stage unchanged. One of five suspected metastatic sites 18 F FDG PET/CT on biopsy was positive for malignancy. Conclusion: The 18 F-FDG PET/CT is useful for staging locally advanced non-inflammatory infiltrating ductal carcinoma of the breast. Use of 18 F-FDG PET/CT was superior to conventional imaging in assessing metastatic mediastinal lymphadenopathy, but with a poor specificity. The use of 18 F-FDG PET/CT in LABC is useful, with the biopsy of isolated suspicious lesions for metastasis increasing its accuracy.