The Relation between Histopathologic Findings on Surgical Specimen and Outcomes in Patients with N2 Positive Stage IIIA Non-Small Cell Lung Cancer Receiving Preoperative Concurrent Radiochemotherapy and Surgery.

Abstract

To evaluate the prognostic implication of histopathologic findings on the surgical specimens of N2 positive stage IIIA non-small cell lung cancer (NSCLC) patients who were treated with preoperative concurrent radiochemotherapy (CRCT) and surgery. From May 1997 to April 2000, 48 patients with N2 positive stage IIIA NSCLC were treated with preoperative CRCT and surgery. Retrospective analyses were performed on 33 patients who underwent surgical resection. The thoracic radiation therapy (TRT) dose was 45 Gy over 5 weeks with a 1.8 Gy daily fraction using 10 MV X-rays. Chemotherapy consisted of two cycles of intravenous cisplatin (100 mg/m2, on days 1 and 29) and oral etoposide (50 mg/m2/day, on days 1~14 and 29~42), concurrently delivered with TRT. Surgery was performed around 4 weeks of the completion of CRCT. The median follow up was 18 months. The histopathologic findings, including the proportions of viable tumor cells, fibrosis, and necrosis, as well as the tumor and nodal statuses on the surgical specimens following the preoperative CRCT, were analyzed. The 3-year overall survival, disease-free survival, and local control rates were 46.1%, 49.5%, and 85.5%, respectively. Post-surgical stages decreased in 18 patients (54.5%), including 3 pathologic complete responses, were unchanged in 13 (39.4%), and increased in two (6.1%). On univariate analyses, the low proportion of the viable tumor cells was the only factor favorably affecting the overall survival rate (p=0.0386), and the histologic type of squamous cell carcinoma was a favorable factor affecting disease free survival rate (p=0.0452). On multivariate analyses, however, no factor affected the overall survival, disease free survival, or local control rates. The histopathologic findings of the proportion of viable tumor cells, fibrosis, and necrosis on the surgical specimens following preoperative CRCT had few prognostic implications on uni-and multi-variate analyses. Furthermore, the primary tumor and nodal responses to preoperative CRCT did not influence the outcomes. Longer-term follow-up with a larger number of patients, however, is awaited.