Stage I pure bronchioloalveolar carcinoma: Recurrences, survival and comparison with adenocarcinoma of the lung

Objective: Bronchioloalveolar carcinoma (BAC) is considered a subtype of adenocarcinoma of the lung, without pleural, stromal or vascular invasion (World Health Organization (WHO) classification). Previous reports had demonstrated a better prognosis following surgery for patients affected by early stage BAC than those affected by other type of non-small cell lung cancer (NSCLC). We aim to analyse differences between stage I peripheral nodular BAC and stage I peripheral adenocarcinoma of the lung, Methods: From January 1, 1993 to December 31, 1999, 1158 patients were submitted to surgical resection for NSCLC. Out of them, 28 patients (2.4%) resulted affected by stage I peripheral pure BAC and 80 (6.9%) by stage I peripheral adenocarcinoma. We made a comparison between these two groups. Results: The percentage of females in BAC patients was similar to that registered in adenocarcinoma patients (21.4 vs. 17.5%). No differences were detected between smokers in BAC and adenocarcinoma patients (P=0.331). The upper lobes were the most common sites of the primary tumour in both tumour subtypes (71.4 vs. 67.5%). Relapse of disease was less frequent in BAC than in adenocarcinoma patients (14.2 vs. 33.7%); recurrent disease developed intrathoracic with higher frequency in BAC patients (75 vs. 33.3%). Both 5-year disease-free and long-term survival were significantly higher in patients affected by BAC (81 vs. 51% and 86 vs. 71%, respectively) (P<0.05); when analysis is performed by dividing stage IA from IB tumours, BAC patients resulted to have higher DFS (stage IA, 93 vs. 58% - P=0.044; stage IB, 61 vs. 32.5%) and higher long-term survival (stage IA, 92 vs. 79%; stage IB, 75 vs. 56%). Conclusion: Patients with stage I pure BAC have significantly longer disease-free and overall survival than those with similar stage adenocarcinoma. Even if classified as subtype of adenocarcinoma, BAC is characterised by clinical behaviour less aggressive than similar stage adenocarcinoma.