Stage III disease accounts for 30% of all new non-small-cell lung cancer (NSCLC) cases per year in the United States. Stages IIIA (T3, N1; T1-3, N2) and IIIB (any T4 excepting malignant pleural effusion or any N3) encompass a heterogeneous population of patients with distinct substages for which widely differing opinions exist regarding the role of surgery, radiation therapy, and chemotherapy. In this issue of ONCOLOGY, Drs. Kelsey, Werner-Wasik, and Marks provide a timely discussion of controversies in the multimodality treatment of such patients and clarify the rationale, if not the role, of radiation therapy as part of definitive, neoadjuvant and adjuvant therapy.
Unresectable Stage III NSCLC
For "unresectable" stage III disease, radiation with chemotherapy is the standard of care. However, considerable debate regarding criteria for resectability exists. Even in patients with technically resectable disease, the question is often not whether their disease can be resected—because increasingly it can be—but whether surgical resection is in their best interest. Regardless, the results of treatment with surgery alone for most categories of clinical stage III disease are poor, with 5-year survival rates of 3% to 9%.[1,2]
Over the past 2 decades, combinations of treatment modalities (chemotherapy, radiation, surgery) have gradually improved survival rates. As the authors demonstrate in their Tables 1 and 2, the 5-year survival rates from phase III studies of unresectable stage III NSCLC treated with concurrent chemoradiotherapy now exceeds 20%. In this same vein, the encouraging results of the Southwest Oncology Group (SWOG) 9504 trial demonstrated a 5-year survival of 29% and a median survival of 26 months in patients with pathologic stage IIIB disease treated with radiation therapy given concurrently with cisplatin(Drug information on cisplatin) and etoposide(Drug information on etoposide) followed by three cycles of consolidation docetaxel(Drug information on docetaxel).[3,4]
Clearly then, combined-modality treatment with chemotherapy and definitive radiation therapy (doses of 60-66 Gy) can be expected to offer good-performance-status patients with N2 mediastinal nodes or stage IIIB disease a 20% to 30% 5-year survival rate. What then might be the value added by surgery in stage III disease?
Potentially Resectable Stage III NSCLC
Preoperative (neoadjuvant) chemotherapy or chemoradiotherapy has several theoretical advantages over postoperative use. These factors have led to several combined-modality studies employing various regimens of neoadjuvant chemotherapy or chemoradiotherapy prior to surgery (Kelsey et al's Tables 4 and 7).
Thus far, however, no phase III study has shown that the addition of surgery to chemoradiotherapy significantly improves survival compared to chemoradiotherapy alone for pathologically staged N2 disease.[5-7] In the Intergroup 0139 study, surgery did improve progression-free survival (22% vs 11%) in a statistically and clinically meaningful way. Although a trend toward improved overall survival at 5 years was observed (27% vs 20%), this difference was not statistically significant, in part due to an excess of treatment-related mortality in the surgical arm, especially in those undergoing right-sided pneumonectomy.
Certainly, surgery may benefit some patients with stage III NSCLC, but additional investigation is necessary to define these subsets. Based on the available data, most lung cancer investigators would agree that patients who should be excluded from a surgical approach include those requiring a pneumonectomy, those with bulky mediastinal N2 or N3 involvement, and the medically inoperable. Patients with limited N2 disease and those achieving complete pathologic clearance of N2 nodes might derive the most benefit from surgery following neoadjuvant therapy.