Radiation therapy for cervical cancer increases risk for colorectal cancer
Young women treated with radiation for cervical cancer should begin colorectal cancer screening earlier than traditionally recommended, according to new research.
The researchers, from the University of Texas Medical Branch at Galveston, found a high incidence of secondary colorectal cancers among cervical cancer survivors treated with radiation. So, they have offered new recommendations that the younger women in this group begin colorectal cancer screening about 8 years after their initial cervical cancer diagnosis instead of waiting until age 50 years. The study was published in Medical Oncology (2014; doi:10.1007/s12032-014-0943-2).
An estimated 18% of malignancies in the United States are secondary cancers that develop in cancer survivors. Previous studies have indicated that cervical cancer survivors treated with radiation have an increased risk for second primary malignancies, yet no preventive recommendations have been established.
This study analyzed 64,507 cervical cancer cases collected from 1973 to 2009 by the National Cancer Institute Surveillance, Epidemiology and End Results program. Among cervical cancer survivors studied, colon, rectum, and anus tumors were found to be 2 to 4 times more frequent in the group treated with radiation than in the group not treated with radiation.
The study found that more than half (52.6%) the patients with cervical cancer studied received radiation treatment. Colon cancer among those treated with radiation began appearing at significantly higher rates approximately 8 years later. After 8 years, the risk for developing colon cancer was double for women who received radiation compared with those who had not. Their risk of rectal cancer quadrupled after 15 years.
After 35 years, women who had received cervical cancer radiation therapy were 3 to 4 times more likely to have developed colorectal cancers than women who had not.
"We are confident from our study that it is time to consider new colorectal cancer screening strategies for cervical cancer survivors," said lead author Ana M. Rodriguez, MD, MPH, assistant professor of obstetrics and gynecology at UT Galveston. "As more people are surviving their cancer diagnosis, we need to learn more about the outcomes 10, 20, 30, even 40 years later and how to take care of their long-term medical needs."