Development and validation of the symptom assessment scale for patients with nasopharyngeal cancer undergoing radiotherapy

Abstract

Objective

This study aims to develop the Symptom Assessment Scale for Patients with Nasopharyngeal Cancer Undergoing Radiotherapy (SAS-NPC), based on the Symptom Experience Model.

Methods

In Phase 1, a content analysis of the literature and group discussions were conducted to construct an initial pool of 61 items. Following expert review by 16 specialists and cognitive interviews with 10 patients, the pool was refined to 56 items. In Phase 2, a convenience sampling method was used to recruit 625 patients with nasopharyngeal cancer (NPC) undergoing radiotherapy, who assessed and explored the scale items. Phase 3 focused on evaluating the scale's reliability and validity.

Results

The SAS-NPC consists of 7 dimensions and 33 items. Reliability analysis revealed a Cronbach's α coefficient of 0.928 for the total scale, a split-half reliability of 0.790, and a retest reliability of 0.828. Validity analysis showed content validity indices for each item ranging from 0.833 to 1.000, with an overall content validity index of 0.970 for the scale. Exploratory factor analysis (EFA) identified 7 common factors, which accounted for 74.505% of the total variance. Confirmatory factor analysis (CFA) demonstrated good overall model fit.

Conclusions

The SAS-NPC comprehensively captures acute and long-term symptoms associated with patients with NPC undergoing radiotherapy. The scale exhibits strong reliability and validity, making it an ideal tool for assessing NPC symptom burden and facilitating clinical symptom management.