title: The Incidence Characteristics of Second Primary Malignancy after Diagnosis of Primary Colon and Rectal Cancer: A Population Based Study.
abstract: BACKGROUND
  With the expanding population of colorectal cancer (CRC) survivors in the United States, one concerning issue is the risk of developing second primary malignancies (SPMs) for these CRC survivors. The present study attempts to identify the incidence characteristics of SPMs after diagnosis of first primary colon cancer (CC) and rectal cancer (RC).
  
  
  METHODS
  189,890 CC and 83,802 RC cases were identified from Surveillance, Epidemiology and End Results Program (SEER) database. We performed rate analysis on incidence trend of SPMs in both CC and RC. Expected incidence rates were stratified by age, race and stage, calendar year of first CRC diagnosis and latency period since first CRC diagnosis. The standardized incidence ratios (SIRs), measure for estimating risk of SPMs, were calculated for CC and RC respectively.
  
  
  RESULTS
  The trends of incidence of SPMs in both CC and RC were decreasing from 1992 to 2012. Both CC and RC survivors had higher risk of developing SPMs (SIRCC = 1.13; SIRRC = 1.05). For CC patients, the highest risks of SPM were cancers of small intestine (SIR = 4.03), colon (SIR = 1.87) and rectum (SIR = 1.80). For RC patients, the highest risks of SPMs were cancers of rectum (SIR = 2.88), small intestine (SIR = 2.16) and thyroid (SIR = 1.46). According to stratified analyses, we also identified incidence characteristics which were contributed to higher risk of developing SPMs, including the age between 20 and 40, American Indian/Alaska Native, localized stage, diagnosed at calendar year from 2002 to 2012 and the latency between 12 and 59 months.
  
  
  CONCLUSIONS
  Both CC and RC survivors remain at higher risk of developing SPMs. The identification of incidence characteristics of SPMs is extremely essential for continuous cancer surveillance among CRC survivors.
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Guan
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Yinghu
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Yinggang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Zhixun
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Yan
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Guiyu
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.|Department of Colorectal Surgery, Cancer Institute & Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Xishan
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D018426:SEER Program; D055815:Young Adult