Sentinel lymph node scintigraphy and radioguided dissection in breast carcinoma: an initial experience at Aga Khan University Hospital.

Objective: To evaluate the efficacy of SLN biopsy using imaging and gamma probe in breast cancer and to establish this technique at Aga Khan University Hospital.

Methods: Thirty two patients (mean age 33-76 yrs) with operable breast carcinoma (4 with post-neo adjuvant therapy) with clinically negative axilla were studied. In 28 patients simultaneous axillary dissection was performed. Sentinel lymph nodes (SLN) scintigraphy was performed a day before surgery by injecting Tc-99m labeled nannocolloid sub-dermally in the peri-areolar region in 24 and peri-tumoral in remaining 8. First lymph node (LN) to appear to on the scan was labeled as SLN and marked on the skin. Blue dye was also injected in all patients and blue and hot LN was explored in the axilla using gamma probe.

Results: The sentinel LN was identified in 31 patients (96.9% success rate) while in one patient (3.1%) SLN was not visualized on the scan (negative study) and this was a post-neo-adjuvant therapy case. The blue dye successfully localized the sentinel LNs in all 32 cases The gamma probe guided localization was successful in all 31 while in one case with post-neo-adjuvant chemotherapy it failed. In 9 out of 32 (28.1%) cases SLN was positive for metastasis and in 6 out of these 9 (66.6%) the SLN was the only metastatic node. This includes the post-neo-adjuvant case as well. There was no case of skip metastasis, i.e. negative SNL and positive other axillary nodes. In remaining 23 (71.9%) cases SLN was negative for metastasis and in all, axilla was free of disease (NPV of 100%).

Conclusion: Lymphoscintigraphy with gamma probe guided SNL biopsy is safe, simple and highly reliable technique. With blue dye technique it reduces the blindness of the procedure if performed independently but increases the cost. Finally, this can accurately stage the axilla, possibly allowing axillary dissection to be foregone in patients where the SLN is clear.