Positron emission tomography using [(18)F]-fluorodeoxy-D-glucose to predict the pathologic response of breast cancer to primary chemotherapy.

PURPOSE: To determine whether [(18)F]-fluorodeoxy-D-glucose ([(18)F]-FDG) positron emission tomography (PET) can predict the pathologic response of primary and metastatic breast cancer to chemotherapy. PATIENTS AND METHODS: Thirty patients with noninflammatory, large (> 3 cm), or locally advanced breast cancers received eight doses of primary chemotherapy. Dynamic PET imaging was performed immediately before the first, second, and fifth doses and after the last dose of treatment. Primary tumors and involved axillary lymph nodes were identified, and the [(18)F]-FDG uptake values were calculated (expressed as semiquantitative dose uptake ratio [DUR] and influx constant [K]). Pathologic response was determined after chemotherapy by evaluation of surgical resection specimens. RESULTS: Thirty-one primary breast lesions were identified. The mean pretreatment DUR values of the eight lesions that achieved a complete microscopic pathologic response were significantly (P =.037) higher than those from less responsive lesions. The mean reduction in DUR after the first pulse of chemotherapy was significantly greater in lesions that achieved a partial (P =.013), complete macroscopic (P =.003), or complete microscopic (P =.001) pathologic response. PET after a single pulse of chemotherapy was able to predict complete pathologic response with a sensitivity of 90% and a specificity of 74%. Eleven patients had pathologic evidence of lymph node metastases. Mean pretreatment DUR values in the metastatic lesions that responded did not differ significantly from those that failed to respond (P =.076). However, mean pretreatment K values were significantly higher in ultimately responsive cancers (P =.037). The mean change in DUR and K after the first pulse of chemotherapy was significantly greater in responding lesions (DUR, P =.038; K, P =.012). CONCLUSION: [(18)F]-FDG PET imaging of primary and metastatic breast cancer after a single pulse of chemotherapy may be of value in the prediction of pathologic treatment response.

Gamma emission imaging in the management of breast disorders.

Breast cancer is the commonest malignancy to affect women. The malignant process may present clinicians with problems in establishing the diagnosis expeditiously, accurately staging the disease and assessing tumour response to primary systemic chemotherapy. Considerable recent interest has focused on the application of imaging techniques that utilize tumour-specific gamma-ray-emitting radiopharmaceuticals to resolve these problems. The wide availability of gamma camera systems makes single photon-imaging techniques, using radiopharmaceuticals incorporating conventional isotopes, attractive options. However, results concerning the detection of the primary breast cancer and the staging of axillary lymph nodes suggest that these techniques would appear to offer no significant advantages, when compared with those obtained using standard diagnostic methods. Dual gamma-ray-emission imaging by positron emission tomography (PET) may offer an alternative solution. Studies performed show that PET can accurately detect primary breast cancers, stage locoregional lymph nodes and visualize distant tumour metastases. Furthermore, PET may be able to monitor early tumour response to chemotherapy agents. It would appear, therefore, that dual gamma emission might have an important role to play in the management of patients with breast cancer.