Spatially fractionated (GRID) radiation for palliative treatment of advanced cancer

Abstract

To evaluate the use of single large doses spatially fractionated radiation (GRID) therapy either alone or in combination with conventional radiation in the palliative treatment of advanced cancer. Sixty-one patients with advanced cancer who had exhausted conventional approaches to palliative treatment with surgery, chemotherapy and/or radiotherapy were treated with high dose GRID therapy using high energy photons. Seventy-two symptomatic areas of disease were irradiated. A 50:50 GRID (open to closed areas) was utilized and a single fraction of 1,000–2,000 cGy to dmax was delivered to the open areas using a single field with either 6 MV or 25 MV photons. Follow-up ranged from 2 weeks to 28 months. Short follow-up times in some patients was due to their end stage disease. Patients were analyzed for palliation of symptoms and normal tissue morbidity. Sixty-four of 72 treatments were evaluable for palliative response. The results of treatment indicated a 27% (17/64) complete palliative response. A partial response was obtained in 64% (41/64). Overall response rate was 91%. Pain was the primary reason for treatment. Twenty-eight percent complete pain relief and 62% partial pain relief was achieved with GRID therapy. Symptoms related to large tumor masses were completely relieved in 19% and partially relieved in 71%. No acute morbidity was observed in spite of the large single doses delivered. Eight patients who were followed 12 to 28 months have shown no late morbidity. The use of spatially fractionated GRID therapy to deliver large single doses of radiation for palliative treatment has proven effective, especially for patients with short life expectancies. Further optimization of the GRID radiation distribution and maximum tolerable doses need to be established. Radiat Oncol Invest 1996;4:41–47. © 1996 Wiley-Liss, Inc.