Background: Radioguided sentinel node biopsy (SNB) of breast cancer patients has become a standard method for detecting early stage breast cancer. However, no standard radiopharmaceutical exists.
Methods: 99mTc rhenium colloid or 99mTc phytate SNB was used to aid detection in breast cancer patients. For each radiopharmaceutical, 100 patients were examined. The following points were compared: (1) scintigraphic detection rate of axillary sentinel nodes (detectability and number when detectable) and internal mammary sentinel nodes; (2) the number of nodes detected scintigraphically and the number detected during surgery; (3) sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for axillary sentinel nodes.
Results: Axillary sentinel nodes of patients were biopsied using either 99mTc rhenium or 99mTc phytate. The number of axillary nodes surgically removed from patients given 99mTc rhenium was 2.28+/-1.08 (mean+/-SD), and the number of axillary nodes surgically removed from patients given 99mTc phytate was 1.68+/-0.82. Some patients given 99mTc rhenium showed a spill-over of radioactivity from sentinel nodes. Concordance of scintigraphically detected nodes and surgical removed nodes was superior for 99mTc phytate compared to that with 99mTc rhenium, with a statistically significant difference. The sensitivity and negative predictive value was superior with 99mTc phytate compared to that with 99mTc rhenium, even though no statistical difference was detectable. However, visualization of internal mammary nodes was superior with 99mTc rhenium.
Conclusion: In breast cancer patients, 99mTc phytate is a better choice for the detection of axillary SNB than 99mTc rhenium colloid. However, 99mTc rhenium colloid is a better choice for the detection of internal mammary nodes.