STAGING OF THE AXILLA IN BREAST-CANCER - ACCURATE IN-VIVO ASSESSMENT USING POSITRON-EMISSION-TOMOGRAPHY WITH 2-(FLUORINE-18)-FLUORO-2-DEOXY-D-GLUCOSE

Objective To evaluate the ability of positron emission tomography (PET ) with F-18-fluoro-2-deoxy-D-glucose (F-18-FDG) to determine noninvasi vely axillary lymph node status in patients with breast cancer. Backgr ound The presence of axillary lymph node metastasis is the most import ant prognostic factor in women with breast cancer. It signifies the pr esence of occult metastatic disease and indicates the need for adjuvan t therapy. The only reliable way in which this important prognostic in formation may be obtained is by performing axillary dissection, which maybe associated with significant complications and delay in discharge from the hospital. PET with F-18-FDG can visualize primary cancers in the breast and metastatic tumor deposits. Methods Fifty patients with untreated breast cancer had clinical examination of their axilla perf ormed (graded as positive or negative), followed by PET of the axilla and midthorax. PET data were analyzed blindly and graded as negative, depending on the presence or absence of axillary nodal metastases. Cyt opathologic assessment of the axillary nodes was carried out within 1 week of PET, by fine-needle aspiration cytology in 5 patients and axil lary dissection in 45; the excised specimens were examined by a single pathologist. Results The overall sensitivity of PET in 50 patients wa s 90% and the specificity was 97%. Clinical examination of the same pa tients had an overall sensitivity of 57% and a specificity of 90%. In the 24 patients with locally advanced breast cancer (T3, T4, TxN2), PE T had a sensitivity of 93% and a specificity of 100%. In T-1 tumors (s even patients), the sensitivity and specificity were 100%. PET had a h igh predictive value (>90%) and accuracy (94%) in staging the axilla. Conclusions PET is a sensitive and specific method of staging the axil la in patients with breast cancer. It may obviate the need for axillar y surgery in women with small primary tumors, define the women likely to benefit from axillary dissection, or allow radiotherapy to be subst ituted for surgery, particularly in post-menopausal women.