Therapeutic strategy for IIIA-N2 non-small cell lung cancer: Perspective of initial surgery plus adjuvant therapy

Background. Postoperative adjuvant chemotherapy for patients with IIIA-N2 non-small cell lung cancer (NSCLC) has been elucidated to improve their 5-year survival rate by 4-5% by a metaanalysis or a recent mega-clinical trial. However, it is still yet to be clarified what population among heterogeneous IIIA-N2 NSCLC or should be indicated or what chemotherapy regimen should be selected. Aim. To consider indication of adjuvant chemotherapy for IIIA-N2 NSCLC, surgical results were retrospectively analyzed. Patients and methods. For 293 patients with IIIA-N2 NSCLC who underwent surgical treatment during 1974-2003, postoperative prognosis was investigated in terms of clinical N (cN) status, period, adjuvant treatments and completeness of resection. Results. Overall survival at 5 years was 21%, and median survival period was 24 months. One hundred and seventy four patients who underwent a complete resection showed a 30% 5-year survival rate whereas the 5-year survival rate was 8% in 110 patients who underwent an incomplete resection (p<0.001). A pleural dissemination and an extranodal invasion of mediastinal lymph node metastasis to surrounding organs were the main reason for incomplete resection, and these were observed in 42 (35%) and 41 patients (34%), respectively. As to the historical periods when the operations were performed, the complete resection rate was 40% in the 1970s, 52% in the 1980s, 68% in the 1990s and 90% in the 2000s, and 3-year survival rates were 13% in the 1970s, 35% in the 1980s, 31% in the 1990s and 70% in the 200Os. Single station N2 cases showed a 36% 5-year survival rate if complete resections were performed. Thirteen patients who underwent an induction chemotherapy exhibited a 100% complete resection rate and 75% 3-year survival rate even though their mediastinal node metastases were bulky or multiple. Conclusions, 1) Complete resection is the most dominant prognostic factor. 2) High resolution CT might improve selection of resectable cases. 3) Resectable single station N2 cases showed an outcome equivalent to the cN0-pN2 population, and may be a candidate for postoperative adjuvant chemotherapy. 4) Induction chemotherapy for marginally respectable cN2 population is hopeful.