ESTRO 2024 - Abstract Book

S2915

Interdiscplinary - Other

ESTRO 2024

Material/Methods:

From March 2022 to October 2023, patients with non-metastatic prostate cancer (stage IVA allowed) seen at the radiotherapy (RT) department were asked to accomplish the EPIC-F along with validated Filipino versions of the International Prostate Symptoms Score (IPSS), International Index of Erectile Function-F (IEFF-5), and EORTC Prostate Cancer Module (PR-25)(for validity testing), at baseline, at 10-14 days later (for reliability testing), and after ≥15 RT sessions (for sensitivity testing).

Data analysis was conducted using JAMOVI Version 2.3.17.0. Pearson correlation, Cronbach’s alpha, and linear regression were utilized for validity, reliability, and sensitivity testing, respectively. Alpha was set at 0.05.

Results:

The validation cohort consisted of 52 patients, aged 54-86 years (70.1 ±6.9), with stage I (15%), II (29%), III (37%), or IVA (19%) disease; 10 (19%) had no biochemical recurrence after prior RT (post-operative, 5; definitive, 5); 42 were for RT (post-operative, 15; definitive, 27); 15 (29%) were on hormonotherapy. Validity. The EPIC-F urinary domain exhibited strong convergent validity with IPSS (r=0.834, p <0.010) and PR-25 urinary scale (r=0.756, p <0.010). There was moderate correlation between the EPIC-F bowel domain and the PR 25 bowel scale (r=0.457, p <0.001), the sexual domain and the IIEF (r=0.551, p <0.011), and the hormonal domain and the PR-25 hormonal scale (r=0.554, p <0.010). These indicate that the EPIC-F measures the same constructs as the validated instruments. EPIC-F sexual, bowel, or hormonal domain scores did not correlate with IPSS scores, while EPIC-F urinary, bowel, or hormonal domain scores did not correlate with IIEF scores. These indicate that they measure separate and non-overlapping constructs, confirming divergent validity. Reliability. The EPIC-F demonstrated high internal consistency in the urinary (Cronbach’s α= 0.866), bowel (Cronbach’s α= 0.815), sexual (Cronbach’s α= 0.844), and hormonal domains (Cronbach’s α= 0.783). These indicate that the questions consistently pertain to their assigned domain.

Test-retest reliability showed moderate correlation between baseline and retest scores for the EPIC-F urinary (0.688, p<0.001), bowel (0.527, p<0.001), and sexual (0.509, p<0.001) domains, indicating stability.

Sensitivity. Sensitivity testing included data from 18 patients aged 56-81 (70.3 ±6.5), with stage II (33%), III (50%), IVA (17%), before and after RT (post-operative - 64Gy/32F, 39%; definitive - 70Gy/28F, 61%). Half were on hormonotherapy. The EPIC-F was found to be sensitive in detecting changes in the urinary (p=0.042), sexual (p=0.001), and hormonal (p<0.001) domains.

Table 1. Psychometric Properties of the EPIC-F

Convergent Validity (n=52)

Domain

Comparison

Correlation Coefficient

p-value

IPSS

0.834

<0.010

Urinary

PR-25 Urinary

0.756

<0.010

Bowel

PR-25 Bowel

0.457

<0.001