title: Clinical course of stage IV invasive mucinous adenocarcinoma of the lung.
abstract: An invasive mucinous adenocarcinoma (IMA) is a distinct lung adenocarcinoma variant. The characteristics of stage IV IMAs are relatively unclear since most previous studies described resected cases from stage I to III. The present study aimed to investigate the clinical course of stage IV IMAs and compare the findings to those of stage IV invasive non-mucinous adenocarcinomas (INMAs).
  
  
  
  The study included 36 IMA patients and 210 INMA patients. The clinicopathological parameters, treatment methods and responses, overall survival (OS), and progression-free survival (PFS) were evaluated.
  
  
  
  IMAs were predominantly located in the lower lobes and frequently presented with multifocal consolidation and lung-to-lung or pleural metastasis. KRAS mutations were noted in 60.0% of the examined IMAs. Non-TKI chemotherapy (CTx) was used in 72.2% of the IMA patients. OS was significantly better in untreated IMA patients than in untreated INMA patients. IMA patients treated with non-TKI CTx had no improvement of OS compared to the untreated IMA patients. However, among INMA patients, OS was best with TKIs in patients harbouring targetable mutations, followed by non-TKI CTx. IMA and INMA patients treated with non-TKI CTx had similar PFS.
  
  
  
  Stage IV IMAs have distinct clinicopathological characteristics, and they might be less aggressive than INMAs. Since non-TKI CTx might not be beneficial in IMA patients, new therapeutic approach is necessary.
authors.affiliation: Department of Pathology, Severance Hospital, Yonsei University College of Medicine, South Korea.
authors.forename: Yoon Jin
authors.initials: YJ
authors.lastname: Cha
authors.affiliation: Department of Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, South Korea.
authors.forename: Hye Ryun
authors.initials: HR
authors.lastname: Kim
authors.affiliation: Department of Radiology, Severance Hospital, Yonsei University College of Medicine, South Korea.
authors.forename: Hye-Jeong
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, South Korea.
authors.forename: Byoung Chul
authors.initials: BC
authors.lastname: Cho
authors.affiliation: Department of Pathology, Severance Hospital, Yonsei University College of Medicine, South Korea. Electronic address: shimhs@yuhs.ac.
authors.forename: Hyo Sup
authors.initials: HS
authors.lastname: Shim
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D002288:Adenocarcinoma, Mucinous / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors
keywords: Lung cancer; Mucinous; Prognosis; Stage IV; Treatment outcome