by Brendon Nafziger
, DOTmed News Associate Editor
Follow-up CT scans for men previously diagnosed with testicular cancer don't appear to up the risk for new tumors, according to a new study.
The study, published Monday online ahead of print in the Journal of Clinical Oncology, tracked thousands of patients, some for nearly a decade.
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Men previously treated for low-grade testicular cancer often have abdominal-pelvic CT scans to monitor for recurring disease. But doctors have long wondered if the ionizing radiation delivered from the scans affect patients' future cancer risk.
Yet in their recent study, a group of Canadian scientists say the scans appear to be safe.
"Second malignancies of the abdomen-pelvis are uncommon in men with low-grade testicular cancer," wrote the researchers, led by Dr. Carl van Walraven of the University of Ottawa. "In this study, the risk of second cancer was not associated with the amount of diagnostic radiation exposure."
The researchers said they used population-based datasets to find every testicular cancer patient in Ontario from 1991 to 2004, excluding only those who had radiation therapy, a previous cancer, retroperitoneal lymph node dissection or were under observation for less than 5 years. Radiation therapy, which uses much higher doses of radiation than CT scans, is linked with cancer recurrence.
The remaining 2,569 men (average age: 35) were observed for a median 11 years -- in general, until the end of 2009, or until they developed a second abdominal-pelvic cancer or died.
These men underwent a median 10 CT scans within the first 5 years of testicular cancer diagnosis, receiving a median radiation exposure of 110 mSv from the scans. Nonetheless, the scans weren't linked with developing a secondary malignancy.
About 14 men -- for a rate of five per 10,000 patients-years of observation -- developed a second tumor, the researchers said, most commonly a colorectal or kidney malignancy.