Whole saliva physico-biochemical changes and quality of life in head and neck cancer patients following conventional radiation therapy: a prospective longitudinal study

We investigated the physico-biochemical changes in saliva and its relation to quality of life (QOL) in head and neck cancer patients following conventional radiation therapy (RT). 53 consecutive head and neck cancer patients underwent conventional RT using telecobalt photons. We analyzed objective sialometry and sialochemical parameters of salivary gland function and a physician reported Oral Assessment Protocol to assess the patients' QOL during (baseline, 3 and 6 weeks) and post RT (3 and 6 months). Statistical analysis was done using SPSS software (version 15.0; SPSS, Inc., Chicago, IL, USA). Stimulated salivary flow rates had shown a consistent decline during and in post-RT analysis (P < 0.001). A significant correlation was seen between mean salivary flow rates at 6 months post-RT and mean salivary electrolytes and amylase levels during the same period (P < 0.001). Mean global QOL scores had significantly worsened during RT and were still significantly poorer at 6 months than initial pre-RT levels (P < 0.001). Further, significant correlation was established between salivary pH values with global QOL scores at 6 months (P = 0.05). Radiation-induced hyposalivation invariably persists and correlates with poor global QOL scores seen during and following conventional RT. Post RT, there is a trend for biochemical reversal toward pre-irradiation levels suggesting a subsiding inflammation or a probable functional recovery.