title: Lymph Node Burden as a Predictive Factor for Selective Chemoradiotherapy in Patients With Locally Advanced Gastric Cancer After a D2 Dissection: A Retrospective Study.
abstract: OBJECTIVE
  The role of adjuvant radiation in locally advanced gastric cancer after a D2 lymph node dissection is not well defined. The Adjuvant Chemoradiation Therapy in Stomach Cancer trial demonstrated a benefit in selected patients with positive lymph nodes. This study further defines lymph node burden as a predictive factor for adjuvant radiation in locally advanced gastric cancer after radical D2 lymph node dissection.
  
  
  METHODS
  One hundred eighty-six patients with locally advanced gastric cancer and D2 dissections were retrospectively investigated. Patients were divided into 2 equal and well-balanced groups based on clinicopathologic characteristics, with half receiving chemoradiation and the other half chemotherapy alone. Clinical outcomes and recurrence patterns were compared. Lymph node ratio (LNR) was defined as ratio of positive to examined nodes. Chemotherapies were fluorouracil-based regimens. Radiation was prescribed to 45 Gy (range, 45 to 50.4 Gy) using 3-dimensional conformal or intensity-modulated radiation therapy techniques.
  
  
  RESULTS
  There was no difference between patients treated with or without radiation in 3-year disease-free survival (DFS) (57.0% vs. 62.0%, P=0.30) or 3-year overall survival (72.8% vs. 77.4%, P=0.23). However, patients with LNR>0.65 or 3 to 6 positive nodes (N2) had improved 3-year DFS and 3-year distant metastasis-free survival (DMFS) in the chemoradiation group (LNR>0.65 vs. LNR≤0.65: 3-y DFS: 35.8% vs. 0%, P=0.052, 3-y DMFS: 75.2% vs. 0%, P=0.026; N2 vs. non-N2: 3-y DFS: 84.7% vs. 57.1%, P=0.046, 3-y DMFS: 100.0% vs. 65.3%, P=0.036).
  
  
  CONCLUSIONS
  N2 or LNR>0.65 may be indications for adjuvant chemoradiotherapy. Further randomized studies are needed for validation.
authors.affiliation: *Department of Radiation Oncology, Shanghai Cancer Center, Shanghai Medical College, Fudan University, Shanghai, P.R. China †Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Qiwen
authors.initials: Q
authors.lastname: Li
authors.forename: Guichao
authors.initials: G
authors.lastname: Li
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Palmer
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000628:therapy*; D000328:Adult; D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy*