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

BACKGROUND: 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. AIM OF THE STUDY: 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. METHODS: 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. RESULTS: 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.

Radioisotopic lymphatic mapping of the sentinel node in melanoma: importance of immunohistochemistry.

BACKGROUND: Elective lymph node dissection (ELND) for patients with malignant melanoma is still controversial. A possible alternative could be biopsy of the first tumor draining lymph node, the sentinel node (SN), which can be identified by means of radionuclide techniques. AIM: Our study was undertaken to assess the accuracy of lymph node biopsy and to stress the importance of immunohistochemistry (IHC) in the pathological assessment of the SN for improved staging of the primary tumor. METHODS: We performed lymphoscintigraphy (LS) in 183 melanoma patients (89 with melanoma of the legs, 11 of the arms and 83 of the trunk). Our protocol consisted of preoperative peritumoral i.d. injection of 99mTc-labeled microcolloid to define the regional lymphatic basin and identify the sentinel node by means of planar scintigraphy. In 147 of the 183 cases a gamma probe (GP) was used during surgery to trace the SN. Vital blue dye was used during surgery in all cases. The SNs were excised for pathological examination. The pathological status of the SN was defined by means of examination of frozen sections, hematoxylin-eosin staining and immunohistochemistry for S-100 and HMB-45 MAb. RESULTS: At least one separate focus of activity was identified by LS in 182 out of 183 patients; in all 147 cases where a GP was used, it was successful in tracing the SN. LS with cutaneous mapping of the SN successfully guided the surgical excision in 177 of the 183 cases; in the 7 remaining cases, i.e. 7 out of 83 cases with SNs in the axillary basin, GP was not used and no elective node dissection was performed. Metastases were found in 39 of these 177 cases. In all 39 cases the SNs were the only positive nodes in the basin. Of the 39 metastases 18 were identified by means of frozen section, 12 by means of hematoxylin-eosin, and 9 by means of immunohistochemistry. We therefore emphasize the importance of immunohistochemistry in the pathology of LS for improved staging of the primary tumor.