Proton therapy at Harvard.

Fractionated precision high-dose proton radiotherapy has been carried out at the Harvard Cyclotron Laboratory (HCL) since 1973, in a collaborative effort with the Radiation Medicine Department of Massachusetts General Hospital (MGH) and the Retina Service of the Massachusetts Eye and Ear Infirmary (MEEI). This paper will discuss proton treatment in general, treatment planning procedures, and results to date in major patient categories. 846 patients have been treated with fractionated proton therapy at the Harvard Cyclotron, with normal tissue and tumor responses consistent with an RBE of 1.1 for the proton beam. Proton beam therapy is the treatment of choice for patients with uveal melanomas, and chordomas and chondrosarcomas involving the skull base and cervical spine. Improved dose distribution possible with protons have allowed greater doses than are given conventionally to be delivered to patients with prostatic carcinoma, head and neck malignancies, ano-rectal cancers, and retroperitoneal tumors. Doses employed have been usually 10 to 20% greater than normally would be delivered in our department to such tumors. Generally, local control rates have been good.