This study aimed to investigate the impact of illness perception on the quality of life (QoL) in patients diagnosed with colorectal cancer (CRC) complicated by ascites. The study explores how patients' cognitive and emotional beliefs about their illness relate to their physical, psychological, and social well-being.

Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide, and many patients are diagnosed at advanced stages with complications such as malignant ascites, which severely impairs quality of life (QoL). Illness perception, the framework of beliefs a patient develops about their illness, is known to influence health outcomes. However, this relationship is not well-studied in the specific subgroup of CRC patients with ascites.

This cross-sectional, observational study was designed to fill this gap. A total of 218 patients with CRC and ascites were enrolled. The study collected clinical and demographic data, and assessed illness perception using the Brief Illness Perception Questionnaire (BIPQ) and QoL using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). The primary goal was to analyze the correlation between dimensions of illness perception and domains of QoL, and to identify independent clinical and demographic factors that predict patient QoL. The findings are intended to inform the development of targeted psychosocial interventions to improve patient well-being in this vulnerable population.

Inclusion Criteria:

• Confirmed diagnosis of colorectal cancer with ascites, verified by imaging and pathological examination.
• Patient and/or legal guardian provided informed consent.
• Karnofsky Performance Status (KPS) score ≥50.
• Estimated survival ≥6 months.

Exclusion Criteria:

• Presence of other active malignant tumors.
• Severe physical disability precluding participation.
• Severe cardiac, hepatic, or renal dysfunction not related to CRC.
• Presence of severe psychiatric or cognitive disorders.
• History of alcohol or drug addiction.

The study population included patients diagnosed with colorectal cancer and concomitant ascites. Participants were recruited from those treated at the Hebei Provincial Hospital of Traditional Chinese Medicine between January 2024 and April 2025. All consecutive patients who met the specific inclusion and exclusion criteria during this period and provided informed consent were enrolled in this cross-sectional study.