What is the optimal intervention for the management and support of xerostomia in patients with Head and Neck Cancer that have undergone radiotherapy?
Background and justification for the study:
Head and Neck cancer (HNC) is one of the most commonly occurring and death-causing cancer worldwide (Epstein & Van Der Waal, 2008). Radiotherapy is used as standard treatment procedure of HNC, often in combination with surgery and/or chemotherapy, the high energy electromagnetic rays (X-rays or γ-rays) used in radiotherapy damages the DNA of the cancer cells resulting in cell death or cell division inhibition (Neeley 2005; Epstein & Van Der Waal, 2008). The radiation dose used for HNC cancer usually exceeds 50Gy. Radiotherapy volumes often contain salivary glands in the proximity of primary disease or entry and exit dose. The salivary glands are sensitive to radiation and therapeutic radiation doses induce its destruction. The saliva post-radiotherapy is reduced in volume, thicker and more acidic causing pain and discomfort to the patient while speaking, chewing and swallowing food; with an associated higher risk of oral infection and dental caries (Acauan et al, 2015 Wang et al, 2016). The prevalence rate of xerostomia is reported in 73.5% – 93% of patients and the complication of it persists in the long-term (6 months to permanent) (Dirix et al, 2008; Pow et al, 2006; Liu et al, 2004). The seriousness of the health issue depends on salivary function before therapy, salivary tissue area exposed radiation total dose, and treatment response of an individual patient (Deasy et al, 2010; Eisbruch et al, 1999). Patient treated may be cured substantially of their cancer (primary disease) but later experience major xerostomia related health issues. Andrews (2001), reported that moderate to severe degree of xerostomia experienced in 64% in long-term survivors (3 years minimum after conventional RT). The major complications of xerostomia are reduced food intake, loss of body weight, and quality of life (QoL).