Breast cancer is the most common cancer in women, although rarely it can appear in men as well. Early breast cancer can be treated with “breast conservation therapy”, involving limited removal of the tumor, sampling of sentinel lymph nodes and whole breast irradiation (with or without chemotherapy depending upon other factors). Tomotherapy produces a very uniform radiation dose through the breast, avoiding “hot spots” which are associated with bothersome skin reactions. This normally requires about 6 weeks of treatment. It may also permit “partial breast irradiation” without requiring an implant. Partial breast irradiation after conservative surgery appears to be as effective as whole breast irradiation in selected women, and only requires 1 week of treatment.

More advanced breast cancer and cancers which have recurred after surgery, radiation, or both might be particularly suitable for Tomotherapy, since treatment can be delivered with one continuous field. This avoids “hot spots” where adjacent fields may overlap during conventional treatment. Since normal heart and lung tissue can be well protected with this technique, long term side effects may be reduced as well.