Surgical outcome in patients with lung adenocarcinoma with mucin.

Objective: Mucin-producing adenocarcinoma is a less common variant of lung adenocarcinoma. Adenocarcinoma cells with mucin can spread through the airspace via mucus-mediated extension, leading to their implantation in distant normal lungs. Consequently, post-operative intrapulmonary recurrence frequently occurs. Mucin-producing adenocarcinomas include not only invasive mucinous adenocarcinoma but also papillary, acinar, and other subtypes. Despite increasing reports on surgical outcomes for invasive mucinous adenocarcinomas, the outcomes for total mucin-producing adenocarcinoma remain unclear.

Methods: We clinically and pathologically evaluated 511 patients who underwent curative resection for lung adenocarcinoma at our institution. The patients were divided into adenocarcinoma with mucin and without mucin groups. Based on pathological findings, the adenocarcinoma with mucin was further classified into intracellular, extracellular, and mucus extension types. Additionally, the CT value of the tumor mass was analyzed using SYNAPSE VINCENT software.

Results: The 5 year overall survival after surgery was 81.5% and 75.9% for patients with adenocarcinoma with versus without mucin (P = 0.774), respectively. The 5 year intrapulmonary recurrence rate in patients with adenocarcinoma with mucin was 29.2%, significantly higher than 12.9% for patients without mucin. Mucus extension was a strong indicator (hazard ratio: 3.03) of intrapulmonary recurrence after surgery. According to SYNAPSE VINCENT analysis, a high volume rate of - 400 HU indicated mucus extension.

Conclusion: Our results demonstrated that intrapulmonary recurrence occurs approximately 2.3 times more often in adenocarcinoma with mucin than in adenocarcinoma without mucin. Mucus extension is a significant risk factor for intrapulmonary recurrence, and surgeons can predict it using SYNAPSE VINCENT analysis.