The effect of Mepitel Film on acute radiation-induced skin reactions in head and neck cancer patients: a feasibility study.

OBJECTIVE: Mepitel Film significantly decreases acute radiation-induced skin reactions in breast cancer patients. Here we investigated the feasibility of using Mepitel Film in head and neck cancer patients (ACTRN12614000932662). METHODS: Out of a total of 36 head and neck cancer patients from New Zealand (NZ) (n = 24) and China (n = 12) recruited between June 2015 and December 2016, 33 patients complied with protocol. Of these, 11 NZ patients followed a management protocol; 11 NZ patients and 11 Chinese patients followed a prophylactic protocol. An area of the neck receiving a homogenous radiation dose of > 35 Gy was divided into two equal halves; one half was randomized to Film and the other to either Sorbolene cream (NZ) or Biafine cream (China). Skin reaction severity was measured by Radiation Induced Skin Reaction Assessment Scale and expanded Radiation Therapy Oncology Group toxicity criteria. Skin dose was measured by thermoluminescent dosimeters or gafchromic film. RESULTS: Film decreased overall skin reaction severity (combined Radiation Induced Skin Reaction Assessment Scale score) by 29% and moist desquamation rates by 37% in the Chinese cohort and by 27 and 28%, respectively in the NZ cohort. Mepitel Film did not affect head movements but did not adhere well to the skin, particularly in males with heavy beard stubble, and caused itchiness, particularly in Chinese patients. CONCLUSION: Mepitel Film reduced acute radiation-induced skin reactions in our head and neck cancer patients, particularly in patients without heavy stubble. Advances in knowledge: This is the first study to confirm the feasibility of using Mepitel Film in head and neck cancer patients.

Couch modelling for volumetric modulated arc therapy (VMAT).

The aim of this work was to investigate the impact of the accuracy of a certain couch model on the overall accuracy of the dose calculation. For this purpose two models of the Varian Exact Couch (Varian Medical Systems, Palo Alto, CA, USA) for use in the planning of volumetric modulated arc therapy (VMAT) were created in Monaco 5.1 (Elekta, Stockholm, Sweden). The first was a simplistic model, with the relative electron densities (ED) of structures based entirely on CT Hounsfield units (HU). The second couch model was obtained by assigning the appropriate EDs to the relevant couch structures. Instead of getting EDs from the CT scan using the Hounsfield units to ED conversion, the second approach was to determine the optimal ED iteratively. The values accepted for the second couch model were the EDs that produced the best agreement between Monaco calculations and the measured couch attenuation. Finally, the performance of the two couch models in clinical prostate VMAT plans was compared.