Background and purpose: We created a scoring system incorporating dosimetric and clinical factors to assess the risk of severe, acute skin reactions in patients undergoing intensity-modulated radiation therapy (IMRT) to treat head and neck cancer (HNC).
Materials and methods: A total of 101 consecutive patients who received definitive IMRT or volumetric modulated arc therapy (VMAT) with a prescription dose of 70 Gy to treat HNC between 2013 and 2017 in our hospital were enrolled. Skin V5Gy, V10Gy, V20Gy, V30Gy, V40Gy, V50Gy, and V60Gy values delivered 5 mm within the body contour were compared between patients with Grades 1-2 and Grade 3 dermatitis. A scoring system was created based on logistic regression analysis (LRA) that identified the most significant dosimetric and clinical factors.
Results: The V60Gy was significantly associated with radiation dermatitis grade in both LRA and recursive partitioning analysis (RPA). A scoring system incorporating the V60Gy, concurrent chemotherapy status, age, and body mass index was used to divide all patients into three subgroups (0-1, 2-3, and 4-6 points) in the RPA. The incidence of Grade 3 dermatitis significantly differed among the subgroups (0, 20.5, and 58.6%, respectively, P < 0.01).
Conclusions: A risk analysis model incorporating dose-volume parameters successfully predicted acute skin reactions and will aid in the appropriate management of radiation dermatitis.
Keywords: Head-and- neck cancer; IMRT; Skin dose; VMAT.