Because advances in therapy have increased long-term survival for women with 
cervical cancer, it is important to study the risk of secondary primary 
malignancies in high-dose organ areas. From the 1973-2009 National Cancer 
Institute Surveillance, Epidemiology, and End Results (SEER) program, we studied 
the risk of developing cancer of the colon and rectum in 64,507 cervical cancer 
patients over 35 years after initial radiation treatment. We also assessed 
change in risk over time. Kaplan-Meier estimator for survival curve and Cox 
proportional hazards models was used. More than half (52.6%) of the cervical 
cancer patients received radiation treatment. In the analyses adjusted for 
race/ethnicity, age, marital status, surgery status, stage and grade, the risk 
of colon cancer between those both with and without XRT diverged beginning at 
approximately 8 years. After 8 years, the hazard ratio for developing colon 
cancer was 2.00 (95% CI 1.43-2.80) for women with radiation versus those without 
radiation treatment. The risk of rectal cancer diverged after 15 years of 
follow-up (HR 4.04, 95% CI 2.08-7.86). After 35 years of follow-up, the absolute 
risk of developing colon cancer was 6.5% for those who received radiation versus 
2.5% for those without, and 3.7 versus 0.8% for rectum. The risk of colon and 
rectum cancer over 20 years of follow-up after radiation remained the same 
across three eras (1973-1980, 1981-1990, and 1991-2000). Radiation-induced 
second cancers of the colon and rectum may occur 8 years after radiation 
treatment for cervical cancer.