Objectives Sentinel node (SN) biopsy in breast cancer has a relatively high
false negative rate, frequently exceeding 10%, for predicting the axillary
nodal status. When the SN is identified using the patent blue dye techniqu
e, we advocate subjecting it to a verification of its blue colour by the pa
thologist as quality control.
Patients and methods One hundred and twenty-two consecutive patients with a
n operable breast cancer underwent a SN biopsy procedure with patent blue d
ye injected peritumourally. The SN biopsy was routinely followed by an axil
lary dissection. Initially each SN was examined histopathologically in a st
andard fashion. Then the non metastatic SNs were checked to ensure that the
y were blue by macroscopic examination of the paraffin blocks in which they
had been embeded. Finally, a search for micrometastasis using immunohistoc
hemistry was performed on all SNs which were non metastatic and confirmed t
o be blue.
Results In 107 (88%) of 122 patients a SN was identified by the surgeon. Af
ter standard histological examination, 32 of 107 SNs proved to contain meta
static tumour. 75 SNs were not metastatic, of which 3 were false negative w
hich would have given a false negative rate of 8.5%(3/35). After checking t
he paraffin blocks of the 75 non metastatic SN, 62 of the 75 were confirmed
blue from which there were 2 false negatives giving a false negative rate
of 5.8% (2/34). The 62 confirmed blue nodes were then assessed for micromet
astasis. 20 nodes proved to be micrometastatic and there remained one false
negative. This gave a final false negative rate of 1.8% (1/53). The false
negative rate was thus reduced from 8.5% to 1.8% after colour quality contr
ol and identification of micrometastasi.
Discussion in this series the procedure of histopathological quality contro
l of the SN identified with the patent blue only technique resulted in a va
luable reduction in the false negative rate. (C) 2001, Masson, Paris.