Radiation therapy has long been used as a viable treatment option for cancer. While its benefits are well proven in a variety of oncological treatment settings, a new study has revealed that its use may have unintended consequences in treating certain types of cancer.
According to a recent news release from the University of Texas Medical Branch at Galveston a group of researchers have revealed for the first time that young women who were previously given radiation treatment for cervical cancer may in fact be at greater risk for developing colorectal cancer as a result of the treatment, and thus should be screened earlier for the disease than when is traditionally recommended.
The new CPRIT-funded study, which was recently posted online on the website for the journal Medical Oncology and featured Dr. Ana M. Rodriguez as lead author along with Dr. Yong-Fang Kuo and Dr. James S. Goodwin, reports a high level of incidence of secondary colorectal cancer diagnoses among survivors of cervical cancer who had been treated with radiation therapy. The UTMB researchers uncovered the findings by analyzing 64,507 cases of cervical cancer that were reported from 1973-2009 and collected by the National Cancer Institute Surveillance, Epidemiology and End Results program. Researchers were able to note by analyzing the data that a palpable number of cervical cancer survivors who received radiation went on to develop other forms of cancer relatively local where they received radiation — including the colon, rectum and anus — which presented a two to four times greater frequency of cancerous tumors, as compared to a test group of patients who did not receive radiation.
The finalized data included the following findings:
- More than half (52.6 percent) the cervical cancer patients studied received radiation treatment. Colon cancer among those treated with radiation began appearing at significantly higher rates approximately eight years later.
- After eight years, the risk for developing colon cancer was double for women who received radiation compared to 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 three to four times more likely to have developed colorectal cancers than women who had not.
The findings of the study do not come as a complete surprise to cancer researchers, as an estimated 18 percent of cancer diagnoses in the U.S. alone are diagnosed as secondary cancers that develop later in cancer survivors, after initial treatment. Specifically, there have been previous studies that pointed out a relationship between cervical cancer survivors exposed to radiation therapy and a rise in second primary malignancies, however, the new UTMB study is unique in that it also lays out specific preventive recommendations in order to curtail these numbers. Namely, the researchers believe that beginning colorectal cancer screenings in previous cervical cancer patients who received radiation should begin around eight years after their initial cervical cancer diagnosis, rather than waiting until age 50.
“We are confident from our study that it is time to consider new colorectal cancer screening strategies for cervical cancer survivors,” said UTMB’s Dr. Ana M. Rodriguez, assistant professor of obstetrics and gynecology and lead author of the study. ”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.”