18F fluorodeoxyglucose imaging with coincidence dual-head gamma camera (FDG Co-PET) for staging and management of locally advanced breast cancer

Full text: To evaluate the role of FDG Co-PET in staging and treatment evaluation of locally advanced breast cancer. Six patients underwent Co-PET for pre-therapy staging of newly diagnosed locally advanced breast adenocarcinoma, based on clinical findings (4 patients based on T4 disease, 2 patients based on supra-clavicular lymphadenopathy) between 11/99 and 8/2000. The treatment consisted of neoadjuvant chemotherapy, followed by radiotherapy (4 patients) or combined partial mastectomy and radiotherapy (2 patients) for local disease control. Restaging with Co-PET was performed on all patients after chemotherapy and in 3 patients after completion of all treatment. Tomography of neck, thorax and abdomen with an ADAC Solus MCD camera was performed (60 minutes after 185 MBq of FDG). Results: Pre-therapy Co-PET demonstrated 100% sensitivity for detection of known disease sites in the breast and regional lymph nodes: axilla (6 patients) and supraclavicular fossa (2). It further detected unsuspected distant metastases in 5 patients: Three were subsequently confirmed by CT or clinical progressive disease: bone (3) and mediastinum (1). It also detected internal mammary chain involvement in 2 patients, with impact on radiotherapy field planning. For assessment of primary breast tumour after chemotherapy, Co-PET showed complete response (CR) in 1 patient and partial response in 5 patients. All remained in long-term clinical remission after radiotherapy and/or surgery (average follow-up: 15 months, range: 7-24 months). Post-chemotherapy Co-PET showed CR in regional lymph nodes in all patients: 2 were confirmed by axillary dissection. One patient subsequently had sub-clinical recurrence in the axilla and supraclavicular fossa detected by surveillance Co-PET. FDG Co-PET showed potential to improve staging and treatment evaluation of locally advanced breast cancer. A significant response demonstrated on post-chemotherapy Co-PET also appeared to predict long-term loco-regional disease control. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc