title: Second primary cancer after surgery for colorectal cancer without lymph node metastasis.
abstract: OBJECTIVE
  Colorectal cancer patients without lymph node metastasis usually show a favorable prognosis with low recurrence rates; however, there is an increased risk of the development of a second primary cancer. Understanding the features of a second primary cancer is important to establish an effective postoperative follow-up program for colorectal cancer without lymph node metastasis.
  
  
  METHODS
  The clinicopathological data on 801 patients with Dukes' A and Dukes' B colorectal cancer were examined in respect to second primary cancer.
  
  
  RESULTS
  In patients with Dukes' A cancer, the incidences of recurrence and second primary cancer were similar. When tumor invasion was limited within subserosa in Dukes' B patients, the incidence of a second primary cancer was almost two-thirds that of recurrence. More than half of the second primary cancers again developed from the colorectum, followed by stomach and lung.
  
  
  CONCLUSIONS
  When colorectal cancer patients without lymph node metastasis show tumor invasion limited within the subserosa, postoperative follow-up should monitor a balance of recurrence with a second primary cancer.
authors.affiliation: Department of Surgery, Clinical Research Institute, National Kyushu Medical Center, Chuo-ku, Fukuoka, 810-8563 Japan. yoikeda@qmed.hosp.go.jp
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Kishihara
authors.forename: Hideki
authors.initials: H
authors.lastname: Saitsu
authors.forename: Motonori
authors.initials: M
authors.lastname: Saku
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Maehara
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology*; D003266:Continuity of Patient Care; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000453:epidemiology*; D016609:Neoplasms, Second Primary / Q000175:diagnosis / Q000453:epidemiology*; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000453:epidemiology