Beyond the lung: Distinct recurrence patterns of mucinous and non-mucinous lung adenocarcinoma after surgery

Abstract OBJECTIVES This study aimed to investigate differences in recurrence patterns between invasive mucinous adenocarcinoma and non-mucinous adenocarcinoma following surgical resection in patients with lung cancer without nodal or systemic metastasis. METHODS We retrospectively analysed the patients’ data who underwent curative surgery for adenocarcinoma between 2011 and 2021. To balance clinical characteristics, 2:1 propensity score matching was performed. Recurrence patterns were classified as either intrapulmonary or extrapulmonary recurrence. Freedom from recurrence and cumulative incidence of recurrence were analyzed to assess differences between groups. RESULTS A total of 4919 patients were included. After matching, 722 patients were non-mucinous group, and 368 patients were mucinous group. The mucinous group exhibited significantly higher freedom from recurrence (p = 0.033) compared to non-mucinous group. The overall recurrence rate was lower in the mucinous group (8.4% vs 13.0%, p = 0.035). Although incidence of intrapulmonary recurrence was comparable between groups (p = 0.50), extrapulmonary recurrence was significantly lower in the mucinous group (p = 0.02). Fine and Gray’s multivariable analysis identified invasive mucinous histology as an independent factor associated with a lower risk of extrapulmonary recurrence (HR = 0.45, 95% CI: 0.22–0.89, p = 0.023). Visceral pleural invasion was a significant predictor for extrapulmonary recurrence (HR = 2.89; 95% CI, 1.37–6.09; p = 0.005). CONCLUSIONS Invasive mucinous adenocarcinoma group demonstrate better recurrence-free survival and a lower risk of extrapulmonary recurrence compared to non-mucinous group following surgical resection. These findings highlight the need for further research aimed at developing tailored surveillance and treatment strategies based on tumour histological characteristics.