An analysis of filtration and volume of radionucleotide in sentinel lymph node biopsy in breast cancer patients.

Controversy has occurred regarding whether to filter or not to filter the radionucleotide and what the optimal volume is when performing sentinel lymph node biopsies. To try and resolve this question we retrospectively looked at sentinel-node biopsies for breast cancer performed at our institution over an 18-month period. One hundred seven patients underwent sentinel node biopsy. Ninety-four patients had an axillary-node dissection. Twelve patients did not have a nodal dissection based on National Surgical Adjuvant Breast and Bowel Project protocol, and one patient refused dissection. Patients fell into three groups: Group I, filtered 8 cm3; Group II, unfiltered 8 cm3; and Group III, unfiltered 16 cm3 (NSABP protocol). Sentinel nodes were identified in 96.3 per cent of Group I, 84.9 per cent of Group II, and 96.3 per cent of Group III. These groups were not statistically different. With the addition of blue dye the ability to identify the sentinel lymph node was for Group I 96.3 per cent, for Group II 96.2 per cent, and for Group III 100 per cent. The false negative biopsy result was 0 per cent for all groups. The patients receiving 16-cm3 volume complained about a greater level of discomfort compared with the lower-volume patients. In conclusion neither the volume nor the filtration process affected the surgeon's ability to find the sentinel lymph node or the false negative rate. The higher injection volumes resulted in more pain. The costs and radiation exposure of the filtration process are not warranted.