Evaluation of preoperative chemotherapy using PET with fluorine-18-fluorodeoxyglucose in breast cancer

We retrospectively investigated the value of PET with fluorine-18 fluorodeoxyglucose (FDG) for preoperative chemotherapy response in patients with locally advanced breast cancer.

FDG-PET studies were performed on 16 consecutive patients. All patients had PET studies before chemotherapy, 13 patients between the end of the first cycle and at the midpoint of chemotherapy, and 14 patients before surgery. Visual diagnoses and the standardized uptake values (SUV) of PET scans were compared with pathology findings at surgery and with the results of mammography, ultrasonography (US) or both, which were performed before chemotherapy and before local surgery for residual disease. Each patient's clinical course was monitored for up to 3 yr.

Sensitivity for detection of pathologically proven primary lesions was 100%, 62.5% and 87.5% with FDG-PET, mammography and US, respectively; and sensitivity for detection of initial nodal involvement was 77%, 70% and 87.5%, respectively. Sensitivity for detection of residual primary tumor was 75%, 71.4% and 87.5%, respectively; and sensitivity for detection of residual nodal involvement was 41.6%, 71.4% and 66.6%, respectively. The mean SUV value of primary lesions was 9.4 (range 2.0-20.7, n = 16), with only two lesions showing an SUV below 3. Clinical improvement of primary lesions was seen in all patients; improvement with smaller size and less FDG uptake was visible as early as the second study in 11 patients (69%). Mean SUV values obtained at the second and third studies decreased significantly from those obtained in the first study. In four patients, the disease recurred after breast surgery with high SUV values. The mammograms and sonograms obtained before surgery showed a decrease in the diameter of 6 and 12 primary lesions of the 13 and 14 patients examined, respectively.

FDG-PET is valuable for monitoring the effects of preoperative chemotherapy in patients with locally advanced breast cancer with better sensitivity for primary tumor and better specificity for nodal metastasis in comparison with ultrasonography.