Lymphoscintigraphy and gamma probe tracing in detecting breast cancer lymph node involvement: can they replace axillary lymph node dissection?

Abstract

Axillary lymph node status is the most important pathological determinant of prognosis in early breast cancer. However, axillary lymph node dissection (ALND) performed for pathological assessment is not without costs and morbidity. Recently, radioisotope-guided sentinel node biopsy (SNB) has been proposed as a promising technique for staging breast cancer patients. In this study we report our experience (76 patients) in radioguided sentinel node (SN) biopsy in breast cancer. The study was divided into two phases: the first represents our learning curve, necessary to establish our guidelines for its use in clinical practice, while the second phase was aimed at assessing the feasibility of SN localization using preoperative lymphoscintigraphy and intraoperative gamma probe (GP) detection. All patients underwent lymphoscintigraphy (LS) up to two hours after tracer delivery (99mTc-micro-nanocolloid, four i.d. injections of 200 microCi/200 miccroL around the primary lesion) 24 hours before surgery and GP tracing during surgery. Subsequently ALND was performed for pathological assessment. SNs were identified in 73/76 patients using LS and in 72/76 using GP. In one case the SN was detected by GP alone while in two cases GP was not able to locate the SN although it had been identified by means of LS. Thirty-three of these 73 patients had axillary node involvement. In 31/33 cases the SN was the only positive node. No positive nodes were found in the remaining 40 ALNDs where SNs were identified. Thus, according to our experience 40/73 ALNDs could have been avoided. SNB seems to be a very interesting technique but further experience in lymph node radioisotope tracing is needed.