[Prognosis and prognostic factor after extended lymphadenectomy in lung cancer]

From 1984 to 1994, 418 patients were received surgery for the lung cancer in our center. Of them, 178 patients were underwent extended lymphadenectomy. Fifty six of the 178 were histologically proven N2 of N3 alpha disease after surgery. Extended lymphadenectomy means R2b lymphadenectomy including the left tracheobronchial node dissection for the right lung cancer and R3 (bilateral mediastinal lymphadenectomy through a median sternotomy) for the left. In the 56 patients, we examined the location and frequency of metastases to the mediastinal lymph nodes and the relationship between some clinical factors (pT, number of metastatic station, clinical staging of the lymph node (CN), histological type, contralateral mediastinal lymph nodes metastases) and prognosis. Most of the pN2 patients of the right lung cancer showed ipsilateral mediastinal lymph nodes metastases and 25 percent of the patients showed the spread to N2b mediastinal modes. The patients of the left lung cancer showed higher incidence of contralateral mediastinal lymph nodes metastases than the patients of the right lung cancer. The five years survival rate of all pN2 patients (N = 39) was 48%, and T1 or T2-N2 patients (N = 22) was 67%. On the other hand, all T4 N2 patients (N-9) died within 3 years after operation. There was no significant difference in postoperative survival between the patients with single station metastasis (N = 20) and multistation metastases (N = 30, including 11 cases with N3 alpha). The five years survival rate of all the patients with multistation metastases was 45%, and that of T1 or T2 multilevel (N = 20) was 65%. There was significant difference in postoperative survival between the patients with CN0-pN2 and CN2-pN2 (p < 0.05). The five years survival of CN0-pN2 patients (N = 14) was 85% and four years survival rate of CN2 pN2 patients (N = 19) was 30%. Among the patients with T1 or T2 tumor, however, there was no significant differences in postoperative survival between CN0-pN2 patients and CN2 pN2 patients. There was no difference in postoperative survival between adenocarcinoma and squamous cell carcinoma (5 years survival: 56%, 43%). In conclusion, extended lymphadenectomy has brought a good prognosis in the patient with T1 or T2 in spite of presence of CN2 or multistation N2. The patients with contralated mediastinal metastases (N3 alpha) showed good prognosis after R3 (5 years survival: 100%) in the patients with the left lung cancer (N = 6). But the N3 alpha patients of right lung cancer showed poorer prognosis (3 years survival: 30%) after R3 (N = 5) than the left. It suggested that R3 lymphadenectomy was significant and beneficial for the left lung cancer patients with N3 alpha but controversial for the right.