Immunostaining for detecting lymph node metastases in non-small cell lung cancer

Objective-To detect lymph node metastases by immunohistochemistry, where previously undetected by routine histopathology. Design-Immunostaining was carried out for high- and low molecular weight cytokeratins, and Ber-EP4 in 13 consecutive lung cancer patients who had undergone systematic mediastinal lymph node dissection. Results Eleven (58%) epidermoid carcinomas, 6 (32%) adenocarcinomas, and 2 (10%) bronchiolo-alveolar carcinomas were detected. These included 4 (21%) stage IA carcinomas, 6 (32%) stage IB, 6 (32%) stage IIB, I (5%) stage IIIB and 2 (10%) stage TV. Immunostaining did not reveal any undetected metastases. Two patients (squamous cell carcinoma T1N0; adenocarcinoma T1N0) had metastases (skeletal; ipsilateral lung) at time of surgery, and one patient (squamous eel carcinoma T2N0) had a regional and systemic relapse 10 months later. Serial sectioning with immunostaining of the lymph nodes from these three patients was also negative. Conclusions-We conclude that, even with the use of immunostaining, negative lymph nodes will not assure a good prognosis, and different determinants probably exist for lymphatic and hematogenic metastases in non-small cell lung cancer.