Background: Clinical diagnosis of the nodal status is a significant factor in determining the treatment and predicting the prognosis in lung cancer patients. A patient with clinical N1 (cN1) disease is usually considered to be a candidate for surgical intervention in the present staging system in non-small cell lung cancer (NSCLC). However, cN1 disease is a subset for which the method of treatment and surgical results are variable, simply because both upstaging and downstaging can occur. We evaluated the surgical and pathologic results of cN1 NSCLC patients to reveal the problems in diagnosis and surgical management for this subset.
Methods: From January 1998 to March 2003, 1,606 patients underwent thoracotomy for primary lung cancer at the National Cancer Center Hospital. Among them, the subjects for this study were 168 (10.5%) NSCLC patients who were clinically diagnosed as having N1 disease and underwent surgery without induction therapy.
Results: The tumor cell types of these 168 cN1 NSCLC patients were adenocarcinoma in 73 (44%) and squamous cell carcinoma in 79 (47%). Pneumonectomy was performed in 26% (n = 43) patients, bilobectomy in 15% (n = 25), and exploratory thoracotomy in 11% (n = 19). Of 19 exploratory thoracotomy cases, 10 cases were due to pleural dissemination. The pathologic nodal status of the 135 patients who underwent pulmonary resection and mediastinal dissection was pN0, 19% (n = 25); pN1, 44% (n = 59); and pN2-3, 37% (n = 51). Of the 55 adenocarcinomas, 60% (n = 33) were revealed to be N2 disease on pathologic examination. There were no significant differences in the serum tumor markers between the pN1 and pN2 groups. Among the 25 patients who were downstaged postoperatively (cN1-pN0), 21 patients (84%) showed obstructive pneumonia in the lung.
Conclusions: In the staging process of cN1 disease, it will be helpful to perform mediastinoscopy and thoracoscopy to avoid unnecessary thoracotomy especially in adenocarcinoma, even though mediastinal nodes and pleural dissemination were negative on computed tomography investigation. Since extensive pulmonary resection (bilobectomy or pneumonectomy) was required in 41% of the patients, preoperative detailed cardiopulmonary function tests should be mandatory to reduce surgical morbidity and mortality. On the other hand, when pneumonia due to airway obstruction by the tumor exists, false-positive hilar nodes can be expected.