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

Abstract

SUMMARY 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. Seventytwo 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 d, was delivered to the open areas using a single field with either 6 M V 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% (41164). 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 Oh. 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.

Dosimetric characteristics of a newly designed grid block for megavoltage photon radiation and its therapeutic advantage using a linear quadratic model

“…Megavoltage GRID radiation therapy is a new paradigm in the management of bulky ͑Ͼ8 cm͒ malignant tumors. [1][2][3][4] The Department of Radiation Medicine at the University of Kentucky has utilized a modified spatially fractionated technique with megavoltage x-ray beam for treatment of advanced tumors. 3,4 Dosimetric characteristics of these GRID radiation fields for both photon and electron beams have been studied by several investigators.…”

“…[1][2][3][4] The Department of Radiation Medicine at the University of Kentucky has utilized a modified spatially fractionated technique with megavoltage x-ray beam for treatment of advanced tumors. 3,4 Dosimetric characteristics of these GRID radiation fields for both photon and electron beams have been studied by several investigators. [5][6][7] It is interesting to know that the published clinical results [1][2][3][4] were obtained with a prototype GRID block that was constructed by placing several segments of copper tubing between two plastic trays and filling the space between the tubes with cerrobend material.…”

“…3,4 Dosimetric characteristics of these GRID radiation fields for both photon and electron beams have been studied by several investigators. [5][6][7] It is interesting to know that the published clinical results [1][2][3][4] were obtained with a prototype GRID block that was constructed by placing several segments of copper tubing between two plastic trays and filling the space between the tubes with cerrobend material. Therefore, the differences in attenuation between the copper tubing and cerrobend material, as well as the nondivergent match problem of the copper tubing to the divergent beam, brought about a challenge to the design of the prototype GRID block.…”

A novel, yet simple MLC‐based 3D‐crossfire technique for spatially fractionated GRID therapy treatment of deep‐seated bulky tumors

“…1 Traditional GRID therapy treatments have shown great tumor response of bulky lesions with an overall response rate increase of 62% to 91% when they were treated with a single-dose of GRID therapy (≥15 Gy) followed by conventional extremal beam radiotherapy. 2 Another study of 71 patients with advanced or bulky tumors of varying histologies demonstrated that 78% response rate for pain palliation and 58.5% and 72.5% objective clinical response rate for mass effect after GRID therapy of 10 to 20 Gy dose with or without additional external beam radiation. 3 All these early clinical studies demonstrated no significant skin toxicity with GRID therapy.…”

Application of Spatially Fractionated Radiation (GRID) to Helical Tomotherapy using a Novel TOMOGRID Template

“…With the advent of the modern megavoltage energy linear accelerator with skin sparing capabilities, the use of GRID technique gradually disappeared. The GRID technique using megavoltage X-ray was started in the late 1980s (1,2) as a palliative treatment of bulky tumors. Currently GRID therapy is performed either by using a commercially available GRID block (3,4) or multileaf collimator (MLC) (5) of a linear accelerator.…”