Clinicopathological features and postoperative prognosis of invasive mucinous adenocarcinoma: a retrospective study

<br><b>Abstract</b><b>Background:</b> Mucinous adenocarcinoma is a rare lung adenocarcinoma subtype, and its biological behavior remains unclear.<b>Methods: </b>We reviewed data of patients with primary lung adenocarcinoma who underwent surgery between January 2016 and December 2017. Overall, 83 patients were included in the invasive mucinous adenocarcinoma (IMA) group, and 1300 were included in the non invasive mucinous adenocarcinoma (non-IMA) group. Clinical characteristics and prognoses of the two groups were compared.<b>Results:</b> In terms of sex, age, smoking history, carcinoembryonic antigen level, and cyfra21-1 level, there were no statistically significant differences between the IMA and non-IMA groups. Compared with non-IMA patients, the local recurrence rate of IMA was significantly higher (51.2% vs. 20.5%). There was no significant difference between two groups in 5-year disease-free survival. However, 5-year overall survival of the IMA group was significantly decreased. In the IMA group, the 5-year OS of pneumonia-type patients was lower than that of nodule-type patients, and pneumonia-type patients included stage II and III exclusively. The 5-year disease-free survival rates in IMA patients was 75.1%, 7.8%, and 14.3% at stages I, II, and III, respectively. The 5-year overall survival rates for IMA patients with stage I, II, and III were 92.4%, 49.7%, and 23.8%, respectively. In multivariate analysis, only the pathological stage was a significant prognostic factor for IMA.<br>