Efficacy of Systemic Treatments in Patients with Metastatic Lung Invasive Mucinous Adenocarcinoma

BackgroundInvasive mucinous adenocarcinoma (IMA) is a rare histological subtype of lung invasive adenocarcinoma with unique clinical, radiological, histopathological, and genomic characteristics. There have been limited studies on the effectiveness of systemic therapy for lung IMA, with conflicting results reported.MethodsWe retrospectively investigated the medical records of patients diagnosed with lung IMA. Patients who were ≥18 years of age and received at least one course of treatment for metastatic or locally advanced inoperable disease were included in the study. Archive records of 113 patients diagnosed with IMA were screened for the study.ResultsA total of 41 patients with lung IMA were included. The targetable mutation rate was 20.6% (in 6 of 29 patients). Most patients (83.1%) had received platinum-based chemotherapy as a first-line treatment. The objective response rate (ORR) was 25.7%, and median progression-free survival (PFS) and overall survival (OS) were 8.1 months (95% CI: 5.02-11.2) and 17.5 months (95% CI: 11.7-23.3 months), respectively, in the patients who received chemotherapy. The median PFS and ORR were 20.6 (95% CI: 18.9-66.5) and 66.6%, respectively, in epidermal growth factor receptor (EGFR) mutation-positive patients (n=3) with relevant targeted therapy. Only one patient used oxaliplatin and capecitabine combination (XELOX) as chemotherapy in the second-line treatment and achieved a partial response at 7.2 months.ConclusionPlatinum-based chemotherapies moderately enhance IMA patients’ survival rates. Anti-EGFR-targeted drugs are seen as potentially effective in patients with EGFR driver mutation positive. Large, prospective studies are needed to confirm our findings.MicroAbstractInvasive mucinous lung adenocarcinoma (IMA) is one of the most lethal malignancies worldwide. In our retrospective study, we aimed to investigate the effectiveness of the standard of care in patients with IMA. We have shown that platinum-based chemotherapies and targeted therapies are effective in patients with IMA. Also, 5-fluorouracil-based chemotherapies may be active in these patients.