Various studies have demonstrated that occult metastases may be present in patients with clinical stage II colon cancer. The objective of this prospective investigation was to compare the performance of molecular analysis and histologic ultrastaging in detecting occult metastases in sentinel lymph nodes (SLNs). SLNs were collected ex vivo during surgery in 29 patients. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) assays were constructed. The results were compared with histologic ultrastaging analysis by hemalum and eosin stain and immunohistochemistry on step serial sections. At least 1 SLN was identified in 76% of the cases. The first hemalum and eosin section identified metastases in 23% of the 22 SLNs. Immunohistochemistry identified isolated tumor cells in 24% of the remaining 17 cases. An overall 73% of the SLNs analyzed by qRT-PCR were positive. Four of them were negative for ultrastaging analysis. qRT-PCR is a powerful tool for the detection of occult metastases in colorectal SLN and seems to be more sensitive than histologic ultrastaging analysis. A larger prospective cohort study is necessary to provide further evidence.
Departments of *Pathology
§Oncology, CHRU Besancon, Besançon
‡Department of Pathology, IUCT Oncopole, Toulouse
∥University of Bourgogne Franche-Comté, UBFC, Bourgogne Franche-Comté, France
This work was financially supported by a research grant from the University Hospital of Besançon (API-CHU 2012).
O.D.: conducted the molecular experiments, analyzed the results, and wrote the manuscript. Z.L. and B.P.: included patients and conducted SLN surgical isolation. D.G.: participated in interpretation of molecular data. F.M.: participated in statistical analysis. S.F.: participated in histologic interpretation. B.H., S.K., C.B., and S.V.-D.: conceived the study and were involved in the study design. B.H.: was the principal investigator of the study. S.V.-D.: is the guarantor of this work. All authors contributed to the critical lecture and final approval of the manuscript.
The authors declare no conflict of interest.
Reprints: Séverine Valmary-Degano, MD, Department of Pathology, CHRU Besançon, Besançon F-25000, France (e-mail: email@example.com).
Received June 7, 2017
Accepted October 22, 2017