Abstract
ObjectivesThe clinical outcomes of patients treated with spatially fractionated GRID radiotherapy (SFGRT) for bulky tumors of the head and neck at a single institution were evaluated retrospectively. Endpoints of interest included tumor response, symptom improvement, treatment tolerance, and adverse events.MethodsInstitutional review board approval was obtained prior to study initiation. The institutional database was queried for patients with tumors of the head and neck treated with SFGRT between August 2007 and April 2015. Medical records of identified patients were reviewed for treatment details and clinical endpoints of interest. SFGRT was delivered in one fraction of 15 gray (Gy) or 20 Gy; 6 megavolt (MV) or 18 MV photon beams were passed through a multileaf collimator (MLC)-based or brass GRID template. All patients had a planned course of conventionally-fractionated external beam radiotherapy (EBRT) to begin on the day following SFGRT delivery.ResultsTwenty-one consecutive patients meeting study criteria were identified. The most common tumor histology was squamous cell carcinoma. Median patient age was 59 years (range 13 - 83 years); median maximum tumor dimension was 9.5 centimeters (cm) (range 5.0 - 25.0 cm). Fifteen patients (71.4%) completed their full course of EBRT. Twelve patients were treated with palliative intent for local tumor symptoms, of which 54.5% experienced some degree of symptom improvement. Of nine patients treated with curative intent, 44.4% achieved a clinical complete response (CR). Concurrent chemotherapy was administered in 12 patients, with all patients being treated having definitively received chemotherapy. Radiation Therapy Oncology Group (RTOG) grade three or higher skin toxicity occurred in five patients; no grade five events were reported.ConclusionsOur institutional experience suggests that SFGRT is a feasible treatment option for the palliative or definitive management of large tumors of the head and neck. In combination with EBRT, SFGRT can provide timely symptom management and improve patient quality of life in the palliative setting. In the definitive setting, the addition of chemotherapy to SFGRT and EBRT can result in an excellent clinical response. Treatment toxicity was found to be within an acceptable range. When considering SFGRT for patients with these challenging presentations, careful patient selection is needed to identify those who will likely tolerate a full course of EBRT following SFGRT, as these patients are most likely to receive maximal benefit from SFGRT treatment. More data on the feasibility and efficacy of this radiation modality will be helpful for continued optimization of SFGRT delivery and patient selection.
Highlights
The treatment of large solid tumors, whether in the setting of palliation or definitive cure, poses a significant clinical challenge
Twelve patients were treated with palliative intent for local tumor symptoms, of which 54.5% experienced some degree of symptom improvement
Our institutional experience suggests that spatially fractionated GRID radiotherapy (SFGRT) is a feasible treatment option for the palliative or definitive management of large tumors of the head and neck
Summary
The treatment of large solid tumors, whether in the setting of palliation or definitive cure, poses a significant clinical challenge. Brachytherapy is a useful local treatment option given the limited associated normal tissue exposure to radiation and the potential for dose escalation, but this technique is frequently limited by tumor location, as well as clinical resources in the form of physician or medical physicist training and equipment not readily available in many centers. An alternate method for the delivery of high dose radiotherapy is spatially fractionated GRID radiotherapy (SFGRT) With this technique, radiation is delivered through evenly spaced holes in a grid template overlying the tumor, resulting in a dose distribution similar to that of interstitial brachytherapy; in lieu of physical catheters, external pencil beamlets send the dose through the holes in the grid template to the tumor volume. Adjacent normal structures are spared using this method as minimal or no clinical or planning margin is added to the tumor volume, in an approach akin to stereotactic radiosurgery [3]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call