Can preoperative lymphoscintigraphy be used as a guide in treatment planning of breast cancer?

Abstract

The purpose of this study was to map the lymphatic drainage patterns of breast cancer with lymphoscintigraphy to evaluate the variability of drainage and to determine whether lymphatic mapping can help to increase the certainty of breast cancer staging. Fifty women with breast cancer (mean age, 49 years) were included in the study. Lymphoscintigraphy was performed with 1 mCi Tc-99m rhenium sulfide colloid in a 2-ml volume injected into the four quadrants of the peritumoral area using a 25-gauge needle. Ten-minute dynamic images and 2-hour delayed static images were obtained in the anterior and lateral positions using a gamma camera with a high-resolution collimator. All patients had a modified radical mastectomy and axillary dissection. The results were evaluated with histopathologic findings of the axilla. Six patients had excision biopsies before surgery. Of 13 patients with centrally located tumors, 84% had axillary lymphatic drainage, whereas 53% drained to internal mammary lymphatics. Of 23 patients with outer quadrant tumors, 4 showed no lymphatic drainage and all of them had metastatic tumor in the axillary lymph nodes. Axillary drainage was seen in 82% of patients and internal mammary lymphatic drainage in 23%. Of eight patients with inner quadrant tumors, one patient with no lymphatic drainage was found to have metastases in the axilla. In this group, 62% had axillary and 50% had internal mammary lymphatic drainage, and one patient had supraclavicular drainage. Lymphoscintigraphy indicates that drainage routes may vary, and thus it may play a guiding role in patients with breast cancer who need radiotherapy. In patients with internal mammary lymphatic drainage, the accuracy of radiotherapy planning may increase if internal mammary lymphoscintigraphy is added to the protocol. In patients with internal mammary drainage, obtaining an internal mammary lymphatic biopsy during surgery will also increase the accuracy of staging.