Relevance of Combined Electron and Photon Beams in Radiotherapy of Head and Neck Cancers in the Era of Intensity-Modulated Radiotherapy

Abstract

Abstract Introduction External beam radiotherapy (EBRT) for head and neck (H&N) cancers continues to be delivered using varied technologies, ranging from the old two-dimensional conventional radiotherapy (2DRT) techniques to the modern three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT) in different centers in India. Due to limitations of spinal cord tolerance, electron and photon beams are combined in 2DRT and 3DCRT techniques for treating nodal volume of the H&N cases. However, many centers having modern technology practice IMRT/VMAT in place of electron beams. The purpose of this study is to analyze the role of combined electron and photon beams in radiotherapy of H&N cancers and its relevance in the modern era of IMRT/VMAT. Materials and Methods Data were collected through a survey conducted on cancer centers in India where radiotherapy is being given by 2DRT, 3DCRT, and IMR/VMAT for the treatment of head and neck cancers. Results The mean percentage of H&N (H&N) cases among all cases were 39.2% (standard deviation [SD]: 14.22), out of which 16.63% (SD: 20.83) were treated with a combination of photon and electron beams and 49.73% (SD: 37.41) were treated with IMRT/VMAT. The average percentage of H&N cases of government institutes was 38.39% (SD: 14.11) and that of private institutes was 40.14% (SD: 14.11). Patients treated with photon and electron combination and IMRT/VMAT were 22.19% (SD: 11.24) and 24.05% (SD: 23.99), respectively, in government institutes, and 10.29% (SD: 11.24) and 79.09% (SD: 26.75) in private institutes. Conclusion As per this study, we conclude that despite the availability of IMRT/VMAT, a combination of electron and photon beams is still relevant in India. Since a large proportion of the patients are still treated with the electron and photon combination, it is imperative that further studies on field–junction dosimetry should be conducted to ensure accurate dose delivery.