A comparative study assessing the different patterns of radiation reactions in head and neckcancer patients undergoing radiation therapy at different times of the day-in the morning versus evening

Background: Human oral mucosa, is a prime target for radiation induced toxicity in patients undergoing radiotherapy for head and neck cancer. The oral cavity is highly susceptible to direct and indirect toxic effects of cancer chemotherapy and ionizing radiation. In our study we investigated the role of chronotherapy with respect to radiation induced mucositis occurring in the normal oral mucosa and treatment response in tumor tissue in cancer patients undergoing radiation therapy to head and neck region. Materials and Methods: This non-randomized clinical study was done to compare the two different timing schedules in the management of head and neck cancer by external beam radiation therapy by cobalt-60 (Theratron780C). In morning arm (arm A), Patients received external beam radiotherapy (EBRT) by cobalt-60 with SSD of 80cm with daily fractions, five days a week, between 8AM–10 AM whereas in evening arm (arm B), patients received EBRT by cobalt-60 with daily fractions, five days a week, between 3PM–5 PM. Both the arms received same radiation regimen. Results: The study concluded that in the morning arm the onset of oral mucositis was observed to be significantly delayed and the duration of mucositis was also significantly shorter as compared to the evening arm. Statistically significant difference in severity of mucositis was found between the two arms. Conclusion: Since there is no active measure to minimize normal tissue toxicity, chronomodulated radiotherapy would be a feasible and cost effective treatment strategy that can be put into clinical practice.