title: Risk factors for double primary malignancies and their clinical implications in patients with sporadic gastric cancer.
abstract: OBJECTIVE
  We carried out a large scale study to identify the risk factors for double primary malignancy (DPM) development in gastric cancer patients and to evaluate the clinical implications for these patients.
  
  
  METHODS
  A total of 2593 patients who underwent gastrectomy for primary gastric cancer from January 2005 to November 2010 were reviewed with regard to DPM. We compared the clinicopathological characteristics, risk factors for developing DPM, and prognosis between the DPM+ group and the DPM- group.
  
  
  RESULTS
  Of the 2593 patients, 152 (5.9%) were diagnosed with DPM. The most common accompanying malignancies were colorectal, lung and thyroid. Multivariate analysis indicated that age (p = 0.016) and MSI status (p = 0.002) were associated with a higher frequency of DPM. 30.3% of patients were diagnosed with DPM within 1 year around perioperative period and 53.3% of patients had DPM detected during 5 years of post-operative follow up periods. Although there was no significant difference in overall survival between the DPM+ and DPM- group, DPM+ patients had a worse prognosis than DPM- patients in stage I gastric cancer.
  
  
  CONCLUSIONS
  Gastric cancer patients over the age of 60 or with a MSI-high status had an increased risk for developing DPM. Further, in stage I gastric cancer, the presence of DPM was associated with a worse prognosis. Therefore, careful pre- and postoperative surveillance is especially important in these patients.
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: I
authors.initials: I
authors.lastname: Cho
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: An
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: I G
authors.initials: IG
authors.lastname: Kwon
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Choi
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Cheong
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: W J
authors.initials: WJ
authors.lastname: Hyung
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea. Electronic address: sunghoonn@yuhs.ac.
authors.forename: S H
authors.initials: SH
authors.lastname: Noh
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001707:Biopsy, Needle; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D009378:Neoplasms, Multiple Primary / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome
keywords: Double primary malignancy; Gastric cancer; Microsatellite instability; Prognosis