Second primary cancer in patients with colorectal cancer after a curative resection

Dig Surg. 2009;26(5):400-5. doi: 10.1159/000229991. Epub 2009 Nov 13.


Background: Colorectal cancer (CRC) patients have an increased risk of developing other malignancies. Understanding the characteristics of the second primary cancer is important to establish an effective surveillance program.

Methods: This study investigated 301 CRC patients to assess the risk factors for postoperative primary cancers arising from organs distinct from the colorectal area (extracolorectal cancers). The observed/expected ratio (O/E ratio) was calculated using the Osaka Cancer Registry, to determine the rate of increase in extracolorectal cancers.

Results: The frequency of postoperative extracolorectal cancers was 12.6%. A logistic regression analysis showed only age to be an independent risk factor for postoperative extracolorectal cancer development. The O/E ratio of overall postoperative extracolorectal cancer was significantly higher than one (O/E ratio 2.6, p < 0.01). In each organ, the frequency of lung and gastric cancers were significantly higher than one, with O/E ratios of 3.2 and 2.7 (p < 0.01 and p < 0.05, respectively).

Conclusion: The frequency of postoperative extracolorectal cancers in CRC patients was significantly higher than that in the normal population, especially for lung and gastric cancers. Clinicians should carefully follow patients for a possible recurrence of CRC and educate CRC patients with regard to the high risk of a second primary cancer.

Publication types

  • Comparative Study

MeSH terms

  • Adenocarcinoma / surgery*
  • Adult
  • Aged
  • Aged, 80 and over
  • Colectomy / methods*
  • Colorectal Neoplasms / surgery*
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Japan / epidemiology
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Neoplasms, Second Primary / epidemiology*
  • Neoplasms, Second Primary / pathology
  • Registries
  • Risk Factors