Sentinel Lymph Node in Pulmonary Carcinoma. Molecular Study After Radioisotope Detection

Abstract Introduction Metastatic lymph node affectation is the main prognostic factor in localised lung cancer. Pathological study of the obtained samples even after an adequate lymphadenectomy presents 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 99 mTc 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 patients were included. Of the tested genes, CEACAM5 and PLUNC were the ones that showed a high expression in lung tissue. Of the 29 analysed 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 tumours. 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.