[Sentinel lymph node in pulmonary carcinoma. Molecular study after radioisotope detection]

Abstract

Introduction: Metastatic lymph node affectation is the main prognostic factor in localized lung cancer. Pathological study of the obtained samples even after an adequate lymphadenectomy, present tumoral relapses of 40% of stage I patients after oncological curative surgery. In this paper we have studied micrometastasis in the sentinel lymph node by molecular methods in patients with stage I lung cancer.

Material and methods: The sentinel node was marked by injecting peritumorally performed just after performing the thoracotomy with 2 mCi of nanocoloid of albumin (Nanocol®) marked with 99mTc in 0.3 ml. Guided with a Navigator® gammagraphic sensor, we proceeded to its resection. RNA of the tissue was extracted and the presence of genes CEACAM5, PLUNC and CK7 in mRNA was studied.

Results: Twenty nine 29 patients were included. Of the tested genes, CEACAM5 and PLUNC were the ones that showed a high expression in lung tissue. Of the 29 analyzed sentinel lymph nodes, 7 (24%) were positive in the molecular study. A positive sentinel lymph node was found in 4/7 adenocarcinomas and 3/12 squamous-cell tumors. Affected lymph nodes were: station 5 (1/3), station 7 (0/6), station 9 (0/1); station 10 (5/11); station 11 (1/1).

Conclusions: Detection of sentinel node in patients with stage I lung cancer by marking with radioisotope is a feasible technique. The application of molecular techniques shows the tumoral affectation in cases staged as stage I.