Background: The objectives of this study were, first, to define the preoperative criteria for using solely the blue dye method and, second, to decrease its operator dependence in predicting axillary lymph node status.
Methods: Two hundred fifty-three women consecutively identified with operable breast cancer underwent sentinel lymph node (SLN) detection by the patent blue dye method followed by completion axillary lymph node dissection. A standard pathological examination was performed for all SLN. Then, a pathological color quality assessment (PCQA), which checked for the presence of the blue dye, was performed on the paraffin blocks of the nonmetastatic SLN. Six preoperative identifiable variables likely to influence the detection rate were examined.
Results: The surgical detection (sd) rate was 84% (213 of 253) and the PCQA rate was 73% (185 of 253). Only breast size (sd, P = .0005; PCQA, P = .0007) and body mass index < or =30 (sd, P = .005; PCQA, P = .0007) were significant for SLN identification. Multivariate analysis revealed two independent factors influencing SLN identification: breast size (sd, P = .0001; PCQA, P = .002) and the timing of injection-injection prior to lumpectomy (sd, P = .04).
Conclusions: The optimal patient features for identifying the SLN by the patent blue dye method are small or medium-sized breasts, low body fat, and that the procedure is carried out prior to tumor excision. The PCQA offers a useful second assessment of the surgically removed SLN, introducing an independent element of quality control.