For women who have had surgery for early breast cancer, it may not matter whether they receive follow-up chemotherapy before, after or during radiation therapy, according to a new review of studies.

A woman's chances of survival or seeing the cancer return are similar in all three cases, if radiation therapy and chemotherapy begin within seven months after surgery, the review concludes.

However, the studies suggest that certain toxic side effects in the blood and esophagus - common in chemotherapy and radiation patients - may be up to 44 percent more likely when the two therapies are delivered at the same time, said Dr. Brigid Hickey and colleagues at the Southern Zone Radiation Oncology Service in Brisbane, Australia.

The reviewers also note that most of the women in the studies were treated about 10 years ago. "As a result, the trials do not assess the modern types of radiotherapy and newer types of chemotherapy" and other anti-cancer drugs such as Herceptin, Hickey said.

Studies show that radiation therapy can reduce the risk of breast cancer returning in the treated breast and boost the likelihood of survival after breast cancer surgery. Doctors may also prescribe chemotherapy to women at high risk for having the cancer spread to other parts of the body after surgery, to reduce the risk of dying from breast cancer.