title: Cumulative radiation exposure during follow-up after curative surgery for gastric cancer.
abstract: OBJECTIVE
  To quantify the cumulative effective dose (cED) of radiation due to repeated CT and PET/CT examinations after curative resection of gastric cancer and to assess the lifetime attributable risk (LAR) estimates based on Biological Effects of Ionizing Radiation VII models.
  
  
  METHODS
  Patients who underwent a curative resection for gastric cancer between January 2006 and December 2006 and were followed-up until May 2010 were included in this study. The cED was calculated by using the dose-length product values and conversion factors for quantitative risk assessment of radiation exposure. cED and LAR were compared between early and advanced gastric cancer patients and among American Joint Committee on Cancer TNM stage groups (stage I, II, and III). The nonparametric Mann-Whitney U and Kruskal-Wallis tests, followed by a post-hoc analysis with Bonferroni adjustment, were employed as part of the statistical analysis.
  
  
  RESULTS
  The overall median cED was 57.8 mSv (interquartile range [IQR], 43.9-74.7). The cED was significantly higher in the advanced (median, 67.0; IQR, 49.1-102.3) than in the early gastric cancer group (median, 52.3; IQR, 41.5-67.9) (p < 0.001), and increased as the TNM stage increased. For radiation exposure, 62% of all patients received an estimated cED of over 50 mSv, while 11% of patients received over 100 mSv. The median LAR of cancer incidence was 0.28% (IQR, 0.20-0.40) and there were significant differences between the early gastric cancer and advanced gastric cancer group (p < 0.001) as well as among the three TNM stage groups (p = 0.015). The LAR of cancer incidence exceeded 1% in 2.4% of the patients.
  
  
  CONCLUSIONS
  The cED increases proportionally along with tumor stage and, even in early gastric cancer or stage I patients, cED is much higher than that found among the general population. Considering the very good prognosis of early gastric cancer after curative surgery, the cED should be considered when designing a postoperative follow-up CT protocol.
authors.affiliation: Department of Radiology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yeo Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Chung
authors.forename: Joon Seok
authors.initials: JS
authors.lastname: Lim
authors.forename: Joo Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Hye-Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Je Sung
authors.initials: JS
authors.lastname: You
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011829:Radiation Dosage; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome