Taste alteration can cause problems such as loss of appetite, inadequate energy intake and weight loss in oncology patients, increasing the risk of malnutrition and negatively affecting the quality of life of patients. It is thought that other problems mentioned can be prevented and quality of life can be improved with effective management of taste alteration. This study was planned as a randomized controlled, pre-test-post-test and experimental design to determine the effect of oral cryotherapy application on chemotherapy-induced taste alteration, thus on appetite level, malnutrition risk and quality of life.

Taste changes disrupt the nutritional plan of patients, causing weight loss and an increased risk of malnutrition, and may negatively affect quality of life. However, this symptom is generally not considered life-threatening and is not considered as important or overlooked by healthcare professionals as other symptoms (nausea, vomiting, oral mucositis, pain, etc.). There is limited data in the literature regarding the management of taste changes in patients receiving chemotherapy. Studies have shown that oral cryotherapy is a method that can be used in the management of taste changes associated with chemotherapy, but more comprehensive studies are needed regarding its effectiveness.Therefore, this study was planned as a randomized controlled, pre-test-post-test and experimental design to determine the effects of oral cryotherapy on chemotherapy-induced taste changes, appetite level, malnutrition risk and quality of life.The patients included in the study will be divided into two groups by simple randomization method: patients who will receive ice cubes in the mouth (intervention/oral cryotherapy group) and patients who will not receive the application (control group).This planned study will be conducted with a total of 70 patients, 35 in the intervention group and 35 in the control group, who received treatment at the Recep Tayyip Erdoğan University Training and Research Hospital Oncology Center, Medical Oncology Department, Outpatient Chemotherapy Unit between July 2024 and July 2025 and who meet the inclusion criteria for the study.Patients who are receiving treatment in an outpatient chemotherapy unit, who can communicate verbally, who are literate, who know their diagnosis, who have an Eastern Cooperative Oncology Group (ECOG) performance score of 2 or below, who are using five chemotherapeutic agents that cause taste alteration alone or in combination (cisplatin, docetaxel, paclitaxel, oxaliplatin, vincristine), who verbally state that they have taste alteration, who do not smoke or drink alcohol or have quit, who do not use statins, hypothyroidism, antidiabetic, antipsychotic, antidepressant, hyperthyroidism, antidepressant, antihistamine, anti-inflammatory, antibiotic or antifungal medications, who do not have Chronic Kidney Disease, metabolic and liver (cirrhosis) disease and who volunteer to participate in the study will be accepted to this study.Patients whose treatment was postponed at least twice in a row, who could not be reached by phone calls, who had a World Health Organization Oral Toxicity Scale score of 1 and above, who had neutropenia (neutrophils; 1000 μL and below), who received radiotherapy to the head and neck region, who had head/neck, stomach and liver cancer, who had tooth sensitivity, who had a changed chemotherapy protocol or who were to be administered a protocol other than the specified agents, who experienced a change in taste before starting the chemotherapy protocol and who did not want to continue the study will be excluded from the study.The data of the study will be collected using the "Introductory Information Form", "ECOG Performance Scale", "World Health Organization Oral Toxicity Scale (WHOTS)", "Chemotherapy-Induced Taste Alteration Scale (C-TAS)", "Simplified Appetite Assessment Questionnaire (SNAQ)", "Malnutrition Universal Screening Tool (MUST)", "Body Mass Index Monitoring Form", "Nutritional Parameters Monitoring Form", "Oral Ice Application Record Form" and "European Organization for Research and Treatment of Cancer Quality of Life Scale (EORTC QLQ-30-Version 3.0)".Before starting the study, the scales and follow-up forms specified for the intervention (oral cryotherapy) and control groups will be filled out by the researcher in a face-to-face interview. The patients in the intervention group will be subjected to oral ice application protocol during three courses (the first course in which the researcher is seen and the second and third courses/an average of two months) at the hospital when they come for treatment, and at home on the days they do not come for treatment, and will be monitored by phone and a reminder message will be sent. During chemotherapy, ice cubes will be applied to the patients in the first hour they start receiving chemotherapy and three consecutive ice cubes (each ice cube takes an average of 1.5-2 minutes to melt/total average of 4.5-6 minutes) during the same period, and the same application will be repeated three hours later. The patients will be asked to apply ice cubes at home six times (an average of 27-36 minutes/day) at two or three-hour intervals for seven days, including the day they receive chemotherapy, and to record their applications on the "Oral Ice Application Follow-up Form".At the end of the study (approximately two months later), the scales will be re-applied to the patients in the intervention and control groups in a face-to-face interview. The pre-test and post-test data from the intervention and control groups will be collected by the researcher using a face-to-face interview technique at a time when the patients are receiving chemotherapy and are available.

Inclusion Criteria:

• Those receiving treatment in an outpatient chemotherapy unit,
• Able to communicate verbally,
• Literate,
• Eastern Cooperative Oncology Group (ECOG) Performance Score of two or below,
• Knowing their diagnosis,
• Taking five chemotherapeutic agents that cause taste changes, either alone or in combination (cisplatin, docetaxel, paclitaxel, oxaliplatin, vincristine),
• Verbally stating that they experience taste changes,
• Not smoking or quitting alcohol,
• Not using statins, hypothyroidism, antidiabetic, antipsychotic, hyperthyroidism, antidepressant, antihistamine, anti-inflammatory, antibiotic and antifungal drugs,
• Not having Chronic Renal Failure (CKD), metabolic (diabetes, thyroid disease, etc.) and liver (hepatitis, cirrhosis) diseases,
• Individuals who volunteered to participate in the study were included in the study.

Exclusion Criteria:

• Patients who have had their treatment postponed at least twice in a row,
• Those with a World Health Organization Oral Toxicity Scale score of 1 and above,
• Those who have received radiotherapy to the head and neck region,
• Those with head/neck, stomach and liver cancer,
• Those who cannot be reached during phone calls,
• Those whose chemotherapy protocol has changed or who will be applied to a protocol other than the specified agents,
• Those with neutropenia (neutrophils; 1000 mcL and below),
• Those with tooth sensitivity,
• Those who have experienced a change in taste before starting the chemotherapy protocol** and
• Those who do not want to continue the study will be excluded from the study.

The data obtained from the study will be collected using a simple randomization method and a computerized randomization program will be used (www.randomizer.org). The groups determined in the program will be the intervention group and the control group; Group 1 and Group 2 will be written on two different papers and will be determined by the chemotherapy unit nurse by drawing lots. Patients who meet the sampling criteria will be divided into two randomized groups as patients who will be applied intraoral ice (intervention group) and patients who will not be applied (control group). Patients who meet the study inclusion criteria will be numbered and delivered to the researcher by the chemotherapy unit nurse on each application day. The patient will be included in the group according to the number given to the patient.