Dyadic Intervention for Psychological Distress of Patients With Colorectal Cancer and Their Spouses

The scale employs a Likert 5-point rating system, ranging from "almost never" to "all the time" with values assigned from 1 to 5 respectively, yielding a total score between 10 and 50. Higher scores indicate greater levels of psychological distress, with a cutoff set at ≥22 points.

The Chinese version of the Illness Cognition Questionnaire comprises three dimensions: helplessness, acceptance, and perceived benefits, each featuring six items, totaling 18 items. It employs a Likert 4-point rating scale, ranging from "completely disagree" to "completely agree." Each dimension is scored independently, with scores ranging from 6 to 24. Higher scores indicate a heightened perception within the respective dimension, and scores from different dimensions are not aggregated.

The scale is designed to evaluate partners' joint coping behaviors in response to shared sources of stress. It utilizes a Likert 5-point rating system, where 1 represents "rarely" and 5 represents "very frequently." Notably, items 7, 10, 11, 15, 22, 25, 26, and 27 are reverse-scored. Additionally, items 36 and 37 assess self-rated satisfaction with binary strategy use and are excluded from the total score calculation. The overall Cronbach's α coefficient for the scale is 0.92, with individual dimension coefficients ranging from 0.67 to 0.91.

The scale, developed by the European Organization for Research and Treatment of Cancer, consists of 30 items. It evaluates five functional domains (physical, emotional, cognitive, social, and role functioning), nine symptom domains (nausea and vomiting, diarrhea, constipation, fatigue, pain, insomnia, appetite loss, dyspnea, and financial difficulties), and one overall health status domain. Scores range from 0 to 100, with higher scores indicating better quality of life. The Cronbach's α coefficient for the overall quality of life scale is 0.809.

Locke-Wallace Marital Adjustment Scale was used to measure marriage quality. Total score was 0-158 points, although higher scores suggest better marriage quality.

Cancer- Related Communication Problems within Couple Scale (CRCP) is a 15- item measure assessing cancer- related communication problems within a cancer couple (e.g. 'My spouse does not ask how cancer affected my life' for patients, and 'My spouse does not ask about how him/her having cancer affects my life' for SCs; Kornblith et al., 2006). Higher scores demonstrate more communication problems within a cancer couple. Coefficient alpha in Chinese cancer patients and their SCs were .805 and .737, respectively (Li et al., 2015).

The Zarit Burden Inventory (Zarit Burden Inventory, ZBI) (Appendix 8) was used to assess the care burden of spouses of colorectal cancer patients. This scale was introduced by Wang Lie et al. [227] in 2006. It consists of 22 items and assesses the social life, economic status, mental status and health status of the primary caregivers in four aspects. The total score ranges from 0 to 88 points. The higher the score, the heavier the care burden. The Cronbach's α coefficient of this scale is 0.87