MONDAY, Nov. 28 (HealthDay News) -- If cancer survivors develop a second cancer, it's most likely to be the same type of cancer as the first, researchers report.
About 15 percent of cancer survivors worldwide are diagnosed with a second primary cancer, the authors of the new report pointed out.
In the study, investigators analyzed data from the entire population of Denmark (7.5 million) from 1980 to 2007 and found that about 10 percent (765,255 people) had one or more diagnoses of primary cancer, for a total of 843,118 diagnoses.
Cancer survivors had a 2.2-fold risk of developing a second primary cancer of the same type as the first type of cancer, and a 1.1-fold risk of developing a different type of second primary cancer, the findings showed.
The risk varied, depending on the type of cancer. The risk of a second cancer of the same type was greatest among sarcoma survivors and lower among prostate cancer survivors. The risk of a second cancer of a different type was highest among larynx cancer survivors and lower among prostate cancer survivors, according to the report published Nov. 28 in CMAJ (Canadian Medical Association Journal).
"The striking contrast between the 2.2-fold increased risk of a second primary cancer being the same type as the first and the 1.1-fold increased risk of it being different from the first cancer suggests that characteristics of the individual patient were involved," wrote study author Dr. Stig Bojesen of Herlev Hospital, Copenhagen University Hospital and the University of Copenhagen, and colleagues. "The risk of a second primary cancer seems to be specific to cancer type and is probably driven by the patient's genetic and lifestyle risk factors."
The U.S. Centers for Disease Control and Prevention has more about cancer survivors.
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