The goal of this observational study is to understand the emotional and physical burden (distress) experienced by cancer patients as they go through radiotherapy treatmen. Researchers want to learn what specific problems such as physical symptoms, financial worries, or travel issues most affect a patient's well-being and how those feelings change over the course of several weeks of care.

The main questions it aims to answer are:

Does high distress lead to negative clinical results, such as missing radiation appointments, significant weight changes, or needing to be admitted to the hospital unexpectedly? Which groups of patients are at the highest risk for severe distress (for example, those with advanced-stage cancer or those using specific types of health insurance)? What are the most common physical, practical, and emotional problems that cause distress during the different phases of treatment?

Participants will:

Complete a survey about their health history and background before treatment begins.

Rate their distress level on a scale of 0 to 10 (using a tool called a Distress Thermometer) and check off specific concerns from a 42-item list each week during their 2 to 8 weeks of radiotherapy.

Complete one final follow-up assessment one month after finishing their radiotherapy treatment.

Study Rationale and Objective: Psychological distress in cancer patients is a recognized catalyst for negative clinical outcomes, yet it remains under-monitored in many tertiary care settings. This research was designed as a prospective longitudinal study to move beyond single-point prevalence surveys and capture the fluctuating nature of distress throughout the radiotherapy (RT) trajectory. The primary objective was to evaluate the longitudinal patterns of distress and identify independent clinical and socioeconomic predictors that correlate with treatment adherence and unplanned healthcare utilization.

Operational Framework: The study tracked a purposive sample of 374 cancer outpatients across eight distinct assessment phases: Baseline (T0): Pre-treatment assessment of demographic, socioeconomic, and clinical status.

Weekly Monitoring (T1-T8): Real-time tracking of distress levels and symptom accumulation throughout the typical 2- to 8-week RT course.

Follow-up (T9): Post-treatment assessment one month after the completion of radiotherapy.

Multidimensional Assessment: Distress was quantified using the NCCN Distress Thermometer (DT), a 0-10 visual analogue scale, with a score≥4 triggering clinical concern. To identify the specific drivers of this distress, participants utilized a 42-item Problem List covering five critical domains:

Physical: Monitoring the accumulation of RT-related side effects such as fatigue, pain, and changes in appearance.

Practical: Identifying logistical barriers, including financial instability (specifically under the Universal Coverage Scheme), transportation difficulties, and work interference.

Psychological: Tracking anxiety, fear, and sadness. Social/Family: Assessing caregiving burdens and relationship stressors. Spiritual: Exploring concerns regarding faith and the meaning of life. Statistical Focus: The study employed multivariate ordinal logistic regression to isolate independent predictors of distress severity while controlling for age and gender. This rigorous analysis aimed to confirm how clinical factors, such as Advanced Cancer Stage (III-IV), and socioeconomic factors, such as Healthcare Coverage type, significantly increase the risk of high psychological burden. By correlating these predictors with tangible clinical outcomes, including significant weight changes, missed appointments, and unplanned hospital admissions, the study provides an evidence-based rationale for a multidisciplinary, holistic nursing approach in oncology departments.

Inclusion Criteria:

• Patients diagnosed with cancer who are receiving treatment through radiotherapy.
• Individuals aged 18 years or older.
• Ability to communicate effectively and understand the Thai language.
• Voluntary agreement to participate in the research project.

Exclusion Criteria:

• Presence of emergency medical conditions or a clinical necessity to receive treatment by other methods.
• Inability to attend follow-up monitoring assessments as dictated by the study protocol.
• Participants who request to withdraw from the project during the study period.
• Failure to complete the full course of radiotherapy treatment due to disease progression.
• A physician's diagnosis of a brain or neurological condition that interferes with the patient's ability to perceive or assess their own symptoms.

Confidentiality Protocols: The study protocol approved by the Institutional Review Board of the Chulabhorn Royal Academy explicitly states that all participant data will be kept strictly confidential and will be presented only as an aggregate overview.

Data Protection: All personally identifiable information has been removed from the final dataset to ensure anonymization.

Data Destruction: In accordance with the ethical considerations defined in the "Methods for maintaining volunteer confidentiality," the investigators have committed to destroying all recording data and deleting the dataset immediately upon the completion of the research project.

Access Restrictions: The protocol specifies that data is stored in a locked secure cabinet accessible only to the primary investigators to prevent unauthorized viewing.

Consequently, there is no plan to share individual participant data (IPD) with outside researchers, as doing so would conflict with the established privacy protections.