title: Role of postoperative radiotherapy after curative resection and adjuvant chemotherapy for patients with pathological stage N2 non-small-cell lung cancer: a propensity score matching analysis.
abstract: BACKGROUND
  The objective of this study was to evaluate the role of postoperative radiotherapy (PORT) in the setting of adjuvant chemotherapy for pathological stage N2 (pN2) non-small-cell lung cancer (NSCLC).
  
  
  METHODS
  A retrospective review of 219 consecutive pN2 NSCLC patients who underwent curative surgery followed by adjuvant chemotherapy was performed. Forty-one patients additionally received PORT. Propensity scores for PORT receipt were individually calculated and used for matching to compare the outcome between patients who did (+) and did not (-) receive PORT. One hundred eleven patients in the PORT (-) group and 38 patients in PORT (+) group were matched. Clinical and pathologic characteristics were well-balanced.
  
  
  RESULTS
  The median follow-up duration was 48 months. In the matched patients, PORT resulted in a significantly lower crude locoregional relapse (43.2% vs. 23.7%; P = .032). Also, PORT was associated with improved locoregional control (LRC) rate (5-year LRC 63.7% vs. 48.6%; P = .036), but not distant metastasis-free survival, disease-free survival (DFS), and overall survival. An exploratory subgroup analysis suggested a potential DFS benefit of PORT in patients with multiple station mediastinal lymph node metastases (5-year DFS, 43.2% vs. 16.6%; P = .037) and squamous cell carcinoma histology (5-year DFS, 70.1% vs. 23.3%; P = .011).
  
  
  CONCLUSIONS
  Even in the setting of adjuvant chemotherapy, PORT significantly increased LRC for patients with curatively resected pN2 NSCLC. Some subgroups appear to benefit from PORT in terms of DFS and LRC. Individualized strategies based on risk factors might be considered.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Byoung Hyuck
authors.initials: BH
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: khjae@snu.ac.kr.
authors.forename: Hak Jae
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hong-Gyun
authors.initials: HG
authors.lastname: Wu
authors.affiliation: Department of Thoracic Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Kang
authors.affiliation: Department of Thoracic Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Young Tae
authors.initials: YT
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Se-Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000628:therapy*; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000628:therapy*; D017024:Chemotherapy, Adjuvant / Q000379:methods; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000628:therapy*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D057216:Propensity Score; D012189:Retrospective Studies; D015996:Survival Rate
keywords: Adjuvant chemotherapy; Non–small-cell lung cancer; Pathologic N2; Postoperative radiotherapy; Propensity score