Scintigraphic sentinel node detection in breast cancer patients: paired and blinded comparison of 99mTc dextran 500 and 99mTc phytate.

BACKGROUND

Breast cancer surgery has evolved towards minimizing morbidity, maximizing cure rates and stratifying treatments according to disease stage. Sentinel lymph node biopsy is becoming standard practice in most centres. However, no standard radiopharmaceutical exists.

OBJECTIVE

To blindly compare 99mTc dextran 500 and 99mTc phytate in the scintigraphic detection of sentinel lymph nodes. Endpoints were the detection of axillary or internal mammary lymph nodes, number of lymph nodes detected, detectability in the first versus the second hour of evaluation and the relationship between rate of detection and age or body mass index.

METHODS

Forty-six patients with histological diagnosis of early breast cancer, without previous surgical treatment, were enrolled in our study. Each patient underwent lymphoscintigraphy twice: on one day with 99mTc dextran 500 and on another day with 99mTc phytate. Images were acquired 1 h and 2 h after tracer administration.

RESULTS

Eighty-eight lymphoscintigraphic studies were performed in 44 patients. On the first image (taken at 1 h), 34 patients from the 99mTc dextran group showed sentinel nodes compared with 28 positive examinations using 99mTc phytate (P = 0.113). On the second image (taken at 2 h) 39 patients from the 99mTc dextran group showed positive results compared to 30 positive examinations using 99mTc phytate (P = 0.036). There was no statistically significant correlation between the body mass index or age and the result of the lymphoscintigraphy.

CONCLUSIONS

99mTc dextran 500 is better than 99mTc phytate for use in a 2 h interval scintigraphic protocol because it demonstrates the sentinel node in a significantly higher number of patients and also showed more lymph nodes suitable for pathological examination.