Clinical relevance of reverse transcriptase-polymerase chain reaction for the detection of axillary lymph node metastases in breast cancer

Background: The mammary sentinel lymph node procedure can increase the detection of axillary metastases by 45% compared with standard axillary dissection. Some investigators have reported that reverse transcriptase- polymerase chain reaction (RT-PCR) increases metastasis detection even more, but it is uncertain whether a positive RT-PCR test in the face of a negative histological evaluation is clinically meaningful. Methods: RT-PCR for epithelial glycoprotein 2 and cytokeratin 19 was performed on sentinel and pooled nonsentinel axillary lymph nodes from 108 women with clinical stage I or II breast cancer who were followed up for a median of 40 months. Results: Axillary metastases were detected on standard tissue sections in 26% and by RT-PCR in 30%. Results for the two tests were concordant for 80% of the cases. RT-PCR upstaged 16%. Tumors from women whose lymph nodes were positive only by RT-PCR were phenotypically similar to those from women with no metastases detected by any method. Moreover, 4-year actuarial distant disease-free survival was 100% for women with metastases detected by RT-PCR only, as compared with 74% for those with metastases detected by routine histology (P = .03) and 93% for those with no metastases detected by either method (P = .04). Conclusions: Analysis of sentinel lymph nodes by RT-PCR for epithelial glycoprotein 2 and cytokeratin 19 is unlikely to provide clinically useful information.