Location as an important predictor of lymph node involvement for pulmonary adenocarcinoma

Abstract

Increasing data implicate histologic grade and radiographic appearance along with tumor size as key prognostic indicators for pulmonary adenocarcinoma. The impact of tumor location on prognosis has not been examined. The records of 530 consecutive patients with pulmonary adenocarcinoma pathologically staged between June 1979 and July 2002 were reviewed. All patients had a preoperative computed tomographic scan of the chest and underwent surgical staging by mediastinoscopy, lymph node sampling, or lymph node dissection. Patients with bronchioalveolar cell carcinoma were excluded. Peripheral tumors were compared with central tumors with regard to stage and survival. A tumor was considered to be central if visualized within the inner third of the lung field or seen bronchoscopically. Patients with T1 cancers were further analyzed on the basis of tumor size. Survival was determined by the Kaplan-Meier analysis and comparisons were made by the log-rank method. Central tumors were more advanced and demonstrated a significantly (P < .0001) poorer survival than peripheral tumors (median 18 vs 39 months). Sixty percent of patients with central tumors had stage III or stage IV disease compared with 25% of those with peripheral tumors. Central T1 tumors, however, demonstrated a 50% incidence of lymph node involvement. Although the incidence of lymph node metastases increased incrementally with the size of peripheral T1 tumors, it remained 50% for central T1 tumors irrespective of size. Tumor location for pulmonary adenocarcinoma should be considered when planning therapy. Central tumors have a high incidence of lymph node metastases (regardless of size) and a poorer prognosis.