Prognosis of early stage pulmonary mucinous adenocarcinoma with different treatments

Background: The effects of surgical approach and adjuvant chemotherapy (AC) of early stage pulmonary mucinous adenocarcinoma (MAD) have not been thoroughly studied yet. This study intends to clarify whether AC provides clinical benefit to the early stage MAD patients and the survival difference between surgical approaches. Methods: All cases of stage I MAD were identified from the SEER database during the period of 2009-2014. The primary cohort was divided into AC and surgery (S) groups. Meanwhile, the patients with tumor <= 1 cm were divided into lobectomy and sublobar resection group. Clinical characteristics, treatments and survival data including overall survival (OS) and cancer-specific survival (CSS) were analyzed. Results: A total of 1,816 patients were included in the final cohort. Referring to surgical procedure, 140 patients received lobectomy and 75 patients received sublobar resection. AC showed worse survival outcomes than surgery alone (OS: 71.2 vs. 93.4 months; CSS: 74.9 vs. 101.1 months). No significant difference was observed between lobectomy group and sublobar resection group (OS: 97.3 vs. 93.1 months; CSS: 103.7 vs. 101.3 months). Consistent results were also shown after the propensity score matching analysis (PSM) was applied. Conclusions: Early stage of MAD has an ideal prognosis. AC may bring adverse effects which would lower OS and CSS of stage I MAD patients. No significant difference is observed in the comparison of prognosis between lobectomy and sublobar resection in tumor size <= 1 cm MAD patients.