Arnadi Shivashankara - Department of Biochemistry, Father Muller Medical College, Mangalore, Karnataka, India
Saira Pais - Department of Radiation Oncology, Father Muller Medical College, Mangalore, Karnataka, India
Paul Simon - Father Muller Research Centre, Mangalore, Karnataka, India
Faizan Kalekhan - Father Muller Research Centre, Mangalore, Karnataka, India
Ashwin Lobo - Department of Biochemistry, Father Muller Medical College, Mangalore, Karnataka, India
Sucharitha Suresh - Department of Community Medicine, Father Muller Medical College, Mangalore, Karnataka, India
Raees Tonse - Department of Radiation Oncology, Father Muller Medical College, Mangalore, Karnataka, India
Thomas George - Father Muller Research Centre, Mangalore, Karnataka, India
Manjeshwar Baliga - Father Muller Research Centre, Mangalore, Karnataka, India

Background: Radiation dermatitis is known to be a major side-effect occurring following cancer treatment. We conducted the present study to understand whether salivary lactate dehydrogenase (LDH) could be conducive to predict the development of radiation-dermatitis in the head and neck cancer (HNC) patients undergoing curative radiotherapy (۶۰-۷۰ Gy).Method: This was a prospective study performed on HNC patients requiring curative radiotherapy. Saliva was collected at two points from the willing volunteers. The first time point was prior to the first fraction of ۲ Gy radiation and the second one was ۲۴ hours after the first fraction and before exposure to the second fraction. The saliva collected at the both time points were analyzed for the levels of salivary LDH using standard procedure. The patients were provided with the standard care throughout the treatment period and the incidence and severity of radiation dermatitis was noted down using a proforma sheet throughout the ۷-week treatment period.Results: The results suggested that with exposure to ۲ Gy fraction, there was an increase in the level of salivary LDH (۳۸۷.۱۱ ± ۱۸.۹۸ IU/L vs. ۳۶۸. ۱۳ ± ۱۹.۵۶IU/L); this increase was significant (t = ۲۰.۰۶ and P < ۰.۰۰۱). The LDH data was stratified based on the severity of dermatitis [mild (grades ۱ and ۲) vs. severe (grades ۳ and ۴)] in accordance to the Radiation Therapy Oncology Group/European Organization for Research and Treatment Cancer (RTOG) grading. The LDH values were subjected to Karl Pearson’s correlation analysis with the grade of dermatitis and the results indicated a P value of ۰.۰۱۹ and R value of ۰.۲۴.Conclusion: For the first time, our study revealed that salivary LDH could be a useful marker to understand the development of radiation-induced dermatitis in HNC patients undergoing curative radiotherapy. The most advantageous aspect herewith is that the collection of saliva does not require skilled people or special equipment; it cou ld be done at repeated intervals and without causing any invasive process.

Head and neck neoplasms, Saliva, Lactate dehydrogenase, Radiotherapy, Radiodermatitis