Dose volume related acute oral toxicities during head and neck cancer irradiation

Purpose: To study the relationship between the Dosimetric Parameters of three-dimensional conformal radiotherapy (3D-CRT) in head and neck cancers (HNC) and the resulting acute oral toxicities.
Materials and Methods: This prospective cohort study consisted of 43 HNC patients with stage (II-IVA) visiting Department of Radiation Oncology, SMS Medical College and Attached Hospitals Jaipur, Rajasthan from May 2019 to April 2020 who received definitive Concurrent Chemo-Radiotherapy (CCRT). Target volume and Organ at Risks (OARs) were identified and contoured as per Radiotherapy Guidelines DAHANCA 2019. During treatment, acute symptoms including oral mucositis, oral pain, xerostomia and dysphagia, were scored weekly during CCRT and at 1 month and 3 month post RT follow up as per CTCAE toxicity criteria (v4.03) and the accumulated scores were related individually in terms of dose–volume variables by studying dose volume histograms (DVH).
Results and Observations: Of total 43 HNC patients (34 male and 9 female), mean age of patients was 55.88 ± 12.08 years. 76% of study population was addicted with regular smoking habit and 15% were having tobacco chewing history while 9% were indulged in smoking and alcohol consumptions both. Study population comprised of 9 oral cavity, 15 oropharyngeal, 6 hypopharyngeal and 15 laryngeal cancer patients. Among the complications (grade ≥2) assessed in the study; dysphagia was the most common to be observed in 83.72% of the study population followed by mucositis and xerostomia seen in 72.09% and 69.76% of patients respectively. When comparing the mean dose and volume of OARs irradiated in the several analyzed structures, it was observed that the patients who developed lower grades (grade≤1) of complications the Dmean and volume (V%) irradiated were smaller in the parotid, oral cavity, constrictors of the pharynx than those who developed higher grades (grade ≥2) of complications. Only one patient developed grade 4 of toxicity and the same patient defaulted with the treatment at week 6 of treatment.
Conclusion: Patients undergoing CCRT treatment for HNC with techniques like 3D-CRT, by considering dosimetric parameters we can spare the OARs better without compromising dose to GTV, the early assessment of toxicities during treatment the probability of late complication of dysphagia and xerostomia can be predicted and the timely intervention of these toxicities can improve the overall quality of life (QOL) of HNC patients. Further studies should be encouraged to define a reasonable and acceptable value of normal tissue tolerance of radiation for routine clinical practice.