Correlation between molecular metastases in sentinel lymph nodes of breast cancer patients and St Gallen risk category.

Aims: To evaluate the clinical significance of tumour metastases detected using real-time reverse transcription-PCR (RT-PCR) in sentinel lymph nodes (SLN) of breast cancer patients.
Methods: Sixty-seven patients with T1-T2 primary breast cancer were included in a prospective study. SLN were analysed for the presence of metastatic tumour cells using standard histopathology staining, immunochemistry (IHC) and multimarker real-time RT-PCR assay for mammaglobin (MMG), carcinoembryonic antigen (CEA) and cytokeratin-19 (CK19) mRNA expression. Correlations between molecular metastases and traditional clinicopathological prognostic factors, including St Gallen risk categories were studied.
Results: Of the 67 patients, 15 (22.3%) had one or more pathology-positive SLN. Five (9.6%) pathology-negative SLN were positive by IHC and 19 (36.5%) by RT-PCR. Of note, RT-PCR analysis was also positive in all cases with pathology- or IHC-positive SLN. MMG was the most informative tumour marker in the panel. Molecularly detected metastases were significantly associated with intermediate St Gallen risk category (p=0.023).
Conclusion: Molecular staging of SLN using real-time RT-PCR for early breast cancer could serve as a useful complement to standard clinicopathological risk factors. Studies with long-term follow-up are necessary to define the impact of molecular metastases on disease free survival and overall survival.