Effect of radical (chemo)radiotherapy on cardiovascular autonomic function in patients with head and neck cancer: a prospective observational study

Purpose Radiotherapy for head and neck cancer irradiates the carotid sinus, yet early effects on cardiovascular autonomic function are poorly described. We prospectively evaluated autonomic function before, at the end of, and six months after definitive radiotherapy with or without concurrent chemotherapy. Methods Thirty-one adults aged 18–74 years with squamous cell carcinoma of the oral cavity, oropharynx, larynx or hypopharynx underwent autonomic function testing at baseline, at the end of treatment and at six months. Each session included a ten-minute supine recording for heart rate and blood pressure variability, followed by deep breathing, Valsalva manoeuvre, lying-to-standing, isometric handgrip and cold pressor tests. Repeated-measures analysis of variance and paired t-tests were used; analyses were exploratory and unadjusted for multiple comparisons. Results Twenty-nine patients completed the end-of-treatment assessment and seventeen the six-month assessment. High-frequency power of heart rate variability was higher than baseline at the end of treatment (P = 0.040) and at six months (P = 0.012). Systolic and diastolic blood pressure and their low-frequency variability increased at the end of treatment but not at six months. Deep breathing, Valsalva, lying-to-standing and handgrip responses did not change. The cold pressor diastolic response showed no overall change (P = 0.093); an isolated baseline-to-six-month difference (P = 0.049) indicated a smaller pressor rise. Conclusion Within six months, conventional autonomic reflex tests showed no significant deterioration, and changes in resting variability were mostly transient. These exploratory findings do not establish baroreflex dysfunction; longer follow-up with direct measurement of baroreflex sensitivity is needed.