Efficacy of reverse transcriptase-polymerase chain reaction screening for micrometastic disease in axillary lymph nodes of breast cancer patients.

Pathologic examination of axillary lymph nodes (ALNs) may miss micrometastases in 30 per cent of breast cancer patients. We have developed a multimarker reverse transcriptase-polymerase chain reaction (RT-PCR)-based screening method that detects histopathologically positive ALNs with a 5 per cent false-negative rate. The purpose of this study was to compare this RT-PCR methodology with histopathology with regard to sensitivity and cost. Pathologically negative ALNs from 35 breast cancer patients were re-evaluated by a single pathologist in a blinded fashion using serial sectioning with immunohistochemical staining. Histopathologic results were then compared with those of RT-PCR. Cost analysis was performed based on standard charges for these methods. RT-PCR identified micrometastases in 14 of 35 pathologically negative nodes. Serial sectioning and immunohistochemical staining identified micrometastases in two cases, with RT-PCR positive for one of these. The charge per specimen for performing routine histopathologic examination was $380, serial sectioning and immunohistochemical staining $787, and RT-PCR $125. RT-PCR appears to be more sensitive at detecting ALN micrometastasis than histopathologic examination even with serial sectioning and immunohistochemical staining. If micrometastatic breast cancer detected by RT-PCR proves to be clinically relevant, it could be a more effective screening methodology with significant cost savings as compared to currently available pathologic examinations.