Is Proton Radiation Therapy Ever Combined With Other Forms of Radiation Therapy or Chemotherapy?

Yes. Conformal proton therapy is often used in conjunction with x-ray therapy. This method boosts the dose to sites of gross disease and allows irradiation of a large volume of tissue. Depending on the amount of cancer within a particular lymph node and the type of cancer that is present, a patient may be at risk for harboring microscopic nests of cancer cells within the nodes. These nodes may lie at some distance from the primary tumor and may not be irradiated if conformal proton treatment alone is delivered to the tumor.

The objective of the treatment plan is to treat both the primary tumor and any areas where a microscopic tumor might hide. X-ray treatment alone will limit the total dose of radiation that can be given, because of the high doses it delivers to large amounts of normal tissue. The solution, therefore, is to use conformal proton beams to treat the primary tumor, and then follow with x-ray therapy to treat the regional nodes. By giving some of the treatment with conformal protons, the total x-ray dose can be reduced substantially.

This reduces the risk of complications and permits treatment of potentially involved lymph nodes. Microscopic cancer within these nodes might be missed if x-rays were not used.