Features of using CT and MRI in planning radiation therapy in patients with squamous cell carcinoma of the head and neck

Abstract

Background. Squamous cell carcinoma of the head and neck (SCCHN) holds a significant position in global oncology. The quality of radiotherapy greatly depends on the accuracy of diagnostic procedures and radiation dosing, as even a minor increase in radiation volume can significantly raise the risk of radiation toxicity. Modern visualization methods and dose calculation algorithms are key in ensuring treatment effectiveness and reducing side effects, thereby improving patients’ quality of life. Purpose. To enhance the effectiveness of radiotherapy for SCCHN through the optimization of topometric preparation using modern visualization methods. Materials and Methods. The study was conducted at the State of Organization «Grigoriev Institute for Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine», from January 2020 to October 2022. The study group comprised 41 cases where radiotherapy planning was performed using both CT and MRI. The comparison group included 64 cases using only CT. Radiation planning was carried out on TPS Eclipse, and irradiation was performed on a Clinac 600C linear accelerator in a classical fractionation mode with a daily dose of 2 Gy to a total dose of 66–70 Gy. Results. The clinical effectiveness of radiotherapy was not dependent on the method of planning, and a reduction in radiation volume by 11% using MRI did not affect the outcomes. It was noted that the development of grade III radiation dermatitis in patients with stage III–IV SCCHN was 2.4 times higher when using only CT compared to using both CT and MRI, which is thought to be due to a larger radiation volume. Grade III radiation mucositis was observed 2.25 times more frequently in the comparison group than in the study group. In patients with stage I–II SCCHN, there was no significant difference in effectiveness and toxicity, hence the use of MRI at these stages is not justified. Conclusions. It is necessary to use MRI with CT for planning radiotherapy in patients with stage III–IV SCCHN. This reduces the risk of grade III radiation dermatitis and mucositis compared to using only CT. For planning radiotherapy in patients with stage I–II disease, the use of CT alone is sufficient.