Factors affecting sentinel node localization during preoperative breast lymphoscintigraphy

Variable success rates for identifying axillary (AX) sentinel nodes in brea st cancer patients using preoperative lymphoscintigraphy have been reported . We evaluated the effects of age, weight, breast size, method of biopsy, i nterval after biopsy, and imaging view on the success of sentinel node iden tification and on the kinetics of radiopharmaceutical migration. Methods: P reoperative breast lymphoscintigraphy was performed in consecutive breast c ancer patients from February 1998 to December 1998. The ipsilateral shoulde r was elevated on a foam wedge and the arm was abducted and elevated overhe ad. Imaging using this modified oblique view of the axilla (MOVA) started i mmediately after peritumoral injection of Millipore-filtered Tc-99m-sulfur colloid and continued until AX sentinel nodes were identified. Anterior vie ws were obtained after MOVA. AX, internal mammary (IM), and clavicular (CL) basins were monitored in all patients. MOVA was compared with the anterior view for sentinel node identification, Age, weight, breast size, method of biopsy, interval after biopsy, and primary tumor location were evaluated f or their effects on sentinel node localization and transit times from injec tion to arrival at the sentinel nodes. Results: Seventy-six lymphoscintigra ms were obtained for 75 patients. AX sentinel nodes were revealed in 75 (99 %) cases. IM or CL sentinel nodes were found in 19 (25%) cases and were not related to tumor location; exclusive IM drainage was present in 1 (1%) cas e. Identification of AX sentinel nodes was equivalent with MOVA and anterio r views in 18 (24%) patients, was better with MOVA in 20 (26%) patients, an d was accomplished only with MOVA in 38 (50%) patients. Median transit time was 17.5 min (range, 1 min to 18 h) after injection, and larger breast siz e was associated with increased transit time. No effect of age, weight, bio psy method, interval from biopsy, or tumor location on transit time was fou nd. Conclusion: Use of MOVA can improve identification of AX sentinel nodes . Although AX drainage is the predominant pattern, a tumor in any portion o f the breast can drain to IM sentinel nodes. Transit time was influenced by breast size. Overall short arrival times with this technique allow sentine l lymph node dissection to be performed on the same day as lymphoscintigrap hy.