Abstract
Radiation therapy continues to evolve and play an ever larger role in the management of primary tumors of the sacrum. Radiation therapy has become much more precise, and the principle advances in radiation have been in the sparing of normal tissues around tumors. Highly conformal photon radiation, carbon ion radiation, and proton radiation are all the so-called high precision radiation delivery methods. This relative sparing allows much higher doses to be delivered to the tumor rendering previously “radiation-resistant” tumors susceptible to radiation's affects. Chondrosarcoma and chordoma have the reputation for being radiation resistant and both are commonly found in the sacrum. However, the literature continues to expand with reports of good local control with radiation as an adjuvant to surgery and, in some cases, as stand-alone treatment. However, the side effects of radiation increase as the dose increases. Even though there is relative sparing of normal tissue, there continues to be off-target effects and the true side effect profile for high precision radiation therapy is not known.