Timing of Radiation and Chemotherapy with Breast Cancer

Last Modified: November 1, 2001

Dear OncoLink "Ask the Experts,"
In patients with node negative breast cancer undergoing radiation therapy after lumpectomy, what is the best timing for radiation therapy with respect to chemotherapy (such as eight 3 week cycles of CMF)?

The optimal timing of radiation therapy and chemotherapy under such circumstances is unclear. There are, however, four options;

  1. Radiation therapy followed by chemotherapy.

  2. Chemotherapy followed by radiation therapy.

  3. Radiation therapy concurrently with cyclophosphamide and 5-FU chemotherapy followed by chemotherapy.

  4. Chemotherapy, then radiation therapy, then chemotherapy again (i.e. "sandwich").
Long delays before beginning radiation therapy (>16 weeks) are associated with an increased risk of local relapse. However, there is no clear evidence that such delays result in decreased chances of survival. There is also no clear evidence that a delay in starting chemotherapy until after XRT is completed results in decreased survival. At the University of Pennsylvania, option #3 is utilized for most patients, though in some patients, option #1 is used.


  1. Overmoyer, B., Fowble, B., Solin L., Goldstein, L., Glick, J.: The long term results of conservative surgery and radiation with concurrent chemotherapy for early stage breast cancer. (Abstract). Proceedings of the American Society of Clinical Oncology 11:90, 1992.

  2. Fowble, B., Solin, L.J., Schultz, D.J., Goodman, R.L.: Ten year results of conservative surgery and irradiation for stage I and II breast cancer. International Journal of Radiation Oncology, Biology, Physics, 21:269-277, 1991


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