Retrospective Observational Study of Oral Complications and Quality of Life in Head and Neck Cancer Patients Treated With Radiotherapy or Chemoradiotherapy.

Radiotherapy, with or without chemotherapy, is the standard treatment for patients diagnosed with head and neck cancer, a disease that accounts for approximately 5% of all cancers diagnosed worldwide and whose incidence is estimated to increase by approximately 64% by 2050. Head and neck cancer is the sixth most common cancer worldwide, with a 5-year survival rate of 50-60%.

Treatment with radiotherapy (RT) or chemoradiotherapy (CRT) in patients with head and neck cancer is frequently associated with the development of acute complications affecting the oropharyngeal cavity, such as oral mucositis, a common toxicity that may lead to multiple functional consequences during oncological treatment. Medium- to long-term complications, also referred to as chronic complications, significantly affect quality of life and include dysphagia, odynophagia, xerostomia, loss of taste, mucosal atrophy, and fibrosis, among others.

Oral mucositis, the most common oral complication during treatment, affects 90-100% of patients with head and neck cancer treated with radiation therapy. The incidence of severe oral mucositis (WHO grade 3-4) in patients with head and neck cancer receiving chemoradiotherapy is approximately 65-70%, whereas in those receiving radiotherapy alone, the incidence is 57%.

In some patients, mucositis may cause significant oral pain that impacts food and fluid intake, leading to serious difficulties and limitations in nutrition and a substantial deterioration in quality of life. Furthermore, in severe cases, oral mucositis may result in additional complications such as infections, treatment interruptions and delays, and even treatment discontinuation.

The literature indicates that severe forms of oral mucositis are responsible for 20-30% of early interruptions in oncological treatment, potentially compromising treatment success and patient survival.

Routine clinical practice for patients with head and neck cancer includes, in addition to RT/CRT, the use of topical agents intended to protect the oral mucosa against treatment-induced toxicity. Standard clinical practice in these patients may include, among other supportive measures, the use of mouthwash and/or topical gel based on natural ingredients olive oil, betaine, and xylitol, an intellectually protected composition (Mucosa Innovations S.L.).

Retrospective studies provide valuable complementary evidence to clinical trials by capturing the effectiveness and safety of treatments in routine clinical practice settings. In this context, the present protocol aims to retrospectively identify patients with head and neck cancer who were exposed, as part of routine daily practice, to the oral mucosal supportive measures described above, while describing the sociodemographic characteristics and clinical variables collected during routine clinical care. The study aims to contribute to a better understanding of, and to help address existing gaps in the management of patients with head and neck cancer.

This protocol describes a retrospective observational study designed to collect data on oral complications and their functional impact in quality of life in patients treated in the Oncological Radiotherapy Unit according to the implemented standard of care for oncological treatment (RT/CRT) and oral mucosal management through topical approachs such as the previously described gel and mouthwash.

The aim of this trial is to identify the presence of oral complications, such as oral mucositis, its severity, time to onset and functional impact on quality of life during treatment in patients with head and neck cancer treated with radiotherapy or chemoradiotherapy, as well as during the post-treatment follow-up period, in patients who received topical oral mucosal care.