title: Clinical outcomes for gastric cancer following adjuvant chemoradiation utilizing intensity modulated versus three-dimensional conformal radiotherapy.
abstract: OBJECTIVE
  To determine if intensity modulated radiation therapy (IMRT) in the post-operative setting for gastric cancer was associated with reduced toxicity compared to 3D conformal radiation therapy (3DCRT).
  
  
  METHODS
  This retrospective study includes 24 patients with stage IB-IIIB gastric cancer consecutively treated from 2001-2010. All underwent surgery followed by adjuvant chemoradiation. Concurrent chemotherapy consisted of 5-FU/leucovorin (n = 21), epirubicin/cisplatin/5FU (n = 1), or none (n = 2). IMRT was utilized in 12 patients and 3DCRT in 12 patients. For both groups, the target volume included the tumor bed, anastomosis, gastric stump, and regional lymphatics.
  
  
  RESULTS
  Median follow-up for the entire cohort was 19 months (range 0.4-8.5 years), and 49 months (0.5-8.5 years) in surviving patients. The 3DCRT group received a median dose of 45 Gy, and the IMRT group received a median dose of 50.4 Gy (p = 0.0004). For the entire cohort, 3-year overall survival (OS) was 40% and 3-year disease free survival (DFS) was 41%. OS and DFS did not differ significantly between the groups. Acute toxicity was similar. Between 3DCRT and IMRT groups, during radiotherapy, median weight lost (3.2 vs. 3.3 kg, respectively; p = 0.47) and median percent weight loss were similar (5.0% vs. 4.3%, respectively; p = 0.43). Acute grade 2 toxicity was experienced by 8 patients receiving 3DCRT and 11 receiving IMRT (p = 0.32); acute grade 3 toxicity occurred in 1 patient receiving 3DCRT and none receiving IMRT (p = 1.0). No patients in either cohort experienced late grade 3 toxicity, including renal or gastrointestinal toxicity. At last follow up, the median increase in creatinine was 0.1 mg/dL in the IMRT group and 0.1 mg/dL in the 3DCRT group (p = 0.78).
  
  
  CONCLUSIONS
  This study demonstrates that adjuvant chemoradiation for gastric cancer with IMRT to 50.4 Gy was well-tolerated and compared similarly in toxicity with 3DCRT to 45 Gy.
authors.affiliation: Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois, United States of America.
authors.forename: Gene-Fu F
authors.initials: GF
authors.lastname: Liu
authors.affiliation: Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois, United States of America.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Bair
authors.affiliation: Departments of Endodontics and Biostatistics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, United States of America.
authors.forename: Eric
authors.initials: E
authors.lastname: Bair
authors.affiliation: Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois, United States of America.
authors.forename: Stanley L
authors.initials: SL
authors.lastname: Liauw
authors.affiliation: Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois, United States of America ; Department of Radiation Oncology, University of Illinois Hospital, Chicago, Illinois, United States of America.
authors.forename: Matthew
authors.initials: M
authors.lastname: Koshy
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000532:radiotherapy; D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy*; D016896:Treatment Outcome