NEW YORK (Reuters Health) - Women treated with chest radiation for cancers in childhood or adolescence are at increased risk for breast cancer at a young age, and their risk does not appear to plateau over time, according to a new study.

Regular screening for breast cancer is a must in these women, and "further research is required to better define the harms and benefits of lifelong surveillance," senior author Dr. Kevin C. Oeffinger, from Memorial Sloan-Kettering Cancer Center, New York, and colleagues note.

The researchers analyzed results from two dozen studies. They found that in women treated with chest radiation at a young age, the rate of breast cancer by age 40 to 45 years was as high as 20 percent.

Once diagnosed, according to the studies, breast cancers among those women were similar to those of women in the general population.

The researchers also found that mammograms can be used to detect breast cancer among women who had chest radiation as children or adolescents.

The investigators note that along with more information on the pros and cons of lifelong surveillance, research is needed to assess "how estimates of risk and outcome might change, given use of lower radiation doses in contemporary treatment."

The study was funded by the National Cancer Institute.

SOURCE: Annals of Intern Medicine, April 5, 2010.