Comparative analysis of clinical features and prognostic factors in resected bronchioloalveolar carcinoma and adenocarcinoma of the lung

Background: Over the past few years, clinical, radiological and pathological classification of lung adenocarcinoma and its subtypes, particularly bronchioloalveolar carcinoma (BAC), has radically changed. Patients and Methods: Out of a series of 384 non-small cell lung cancer (NSCLC) patients, submitted to surgical resection and followed-up in our Department from 1981 to 1999, the data of 151 adenocarcinomas (35 BAC and 116 non-BAC) were reviewed and analyzed for prognosis. Results: BAC and non-BAC series were similar in clinical and radiographic findings, type of resection and stage. Stage I was a dominant favorable prognostic factor (10-year survival: 58% of BAC, 41.2% of non-BAC), albeit associated with a significant risk of second primary metachronous lung tumor (10-year risk: 25% of BAC, 32% of non-BAC). Other independent prognostic factors were: absence of lymph node involvement for BAC and stage III-IVfor non-BAC. In term of prognosis, advantages of BAC over non-BAC were fewer cases with lymph node involvement, increased presence of "well-differentiated" cells (p = 0.016) and lower incidence of a second primary metachronous tumor. Moreover BAC patients with a single nodule or mass also had a higher survival expectancy (mean survival: 77 months versus 56 for non-BAC). An unfavorable feature was the higher incidence of diffuse or multicentric radiological forms (p=0.012). For both groups the presence of multiple or satellite nodules remain a diagnostic and surgical challenge: in BAC cases the evaluation of clonality is recommended.