The German version of the Expanded Prostate Cancer Index Composite (EPIC): translation, validation and minimal important difference estimation

The Romanian translation and validation of the Extended Prostate Cancer Index Composite in patients undergoing radical prostatectomy

Background and aims

To evaluate the quality of life in patients treated for prostate cancer in detail, an accessible, extensive, and easy-to-administer questionnaire is needed. The self-administered 50-item "Expanded Prostate Cancer Index Composite" (EPIC) is an instrument used for this purpose, but it is not officially translated into Romanian. The aim of the study was to translate and validate the Romanian version of the EPIC.

Methods

We translated and culturally adapted the EPIC into Romanian. For validation, we included a retrospective analysis of 112 patients who underwent robotic radical prostatectomy and a prospective study including 120 consecutive patients hospitalized before surgical treatment. Baseline and follow-up assessments took place before and at six months, two, and five years post-surgery, between January 2014 and December 2015. We performed cross-sectional correlations between the EPIC, AUASI, and SF-12 at baseline, factor analysis, and calculated the internal consistency.

Results

For most EPIC domains and subscales, our a priori-defined criteria for reliability were fulfilled (Cronbach's alpha 0.7-0.9). Cross-sectional correlations between EPIC scales and AUASI domain ranged from 0.23-0.69, and SF-12 domains ranged from 0.21-0.53 and 0.22-0.61, respectively. The retrospective analysis showed a medium acceptability and understanding of the EPIC questionnaire. In the prospective study, the revised EPIC draft showed an overall higher acceptability with a responding rate of 66% at a 5-year follow-up. All domains exhibited good internal consistency except for the hormonal section (Cronbach's α = 0.67) at the 6-month follow-up.

Conclusion

The Romanian version of the EPIC is reliable, responsive and valid for measuring HRQL in prostate cancer patients. The EPIC questionnaire proved to be an exhaustive and reproducible instrument for evaluating the quality of life in Romanian prostate cancer patients.

Converting between the International Prostate Symptom Score (IPSS) and the Expanded Prostate Cancer Index Composite (EPIC) urinary subscales: modeling and external validation

BACKGROUND

Prostate-related quality of life can be assessed with a variety of different questionnaires. The 50-item Expanded Prostate Cancer Index Composite (EPIC) and the International Prostate Symptom Score (IPSS) are two widely used options. The goal of this study was, therefore, to develop and validate a model that is able to convert between the EPIC and the IPSS to enable comparisons across different studies.

METHODS

Three hundred forty-seven consecutive patients who had previously received radiotherapy and surgery for prostate cancer at two institutions in Switzerland and Germany were contacted via mail and instructed to complete both questionnaires. The Swiss cohort was used to train and internally validate different machine learning models using fourfold cross-validation. The German cohort was used for external validation.

RESULTS

Converting between the EPIC Urinary Irritative/Obstructive subscale and the IPSS using linear regressions resulted in mean absolute errors (MAEs) of 3.88 and 6.12, which is below the respective previously published minimal important differences (MIDs) of 5.2 and 10 points. Converting between the EPIC Urinary Summary and the IPSS was less accurate with MAEs of 5.13 and 10.45, similar to the MIDs. More complex model architectures did not result in improved performance in this study. The study was limited to the German versions of the respective questionnaires.

CONCLUSIONS

Linear regressions can be used to convert between the IPSS and the EPIC Urinary subscales. While the equations obtained in this study can be used to compare results across clinical trials, they should not be used to inform clinical decision-making in individual patients.

TRIAL REGISTRATION

This study was retrospectively registered on clinicaltrials.gov on January 14th, 2022, under the registration number NCT05192876.

Missingness in the expanded prostate cancer index short form (EPIC-26) - prevalence, patterns, and explanatory factors

BACKGROUND

Researchers and clinicians using common clinical assessments need to attend to the prevalence of missing data to ensure the validity of the information gathered. The Expanded Prostate Cancer Index Short Form (EPIC-26) is a commonly used measurement scale used for assessing patients' quality of life, but the measure lacks comprehensive analysis on missing data. We aimed to explore the quantity of missing answers in EPIC-26 and to characterize patterns and possible explanations of missing data in the survey.

METHODS

The survey sample consisted of 625 Finnish prostate cancer patients who participated in a study with a 1-year follow-up with three measurement points (0, 6, and 12 months). Descriptive statistics were used to describe the study population and missingness level. A logistic regression was performed for each EPIC domain to study factors related to missingness during the follow-up.

RESULTS

Proportions of missing answers in EPIC-26 were low (3.1-3.9%) between survey rounds. As much as 37% of patients left at least one question unanswered during their follow-up. The hormonal domain produced the most missing answers. Questions about breast tenderness/enlargement (question 13.b.), hot flashes (question 13.a.), frequency of erections (question 10.), and ability to reach orgasm (question 8.b.) were most frequently left unanswered. Higher age, lower education level, no relationship, more severe cancer, lower function scores in some EPIC domains, lower treatment satisfaction or self-rated health were associated with missingness.

CONCLUSIONS

Questions 13.b. and 13.a. might be considered female-specific symptoms, thus difficult to comprehend unless patients had already experienced side effects from androgen deprivation therapy. Questions 10. and 8.b. might be difficult to answer if the patient has been sexually inactive. To improve the measure's validity, the questionnaire's hormonal section requires additional explanation that the inquired symptoms are common treatment side effects of anti-androgen therapy; questions 8-10 require a not-applicable category for sexually inactive patients.

Dose-Volume Histogram Parameters and Quality of Life in Patients with Prostate Cancer Treated with Surgery and High-Dose Volumetric-Intensity-Modulated Arc Therapy to the Prostate Bed

INTRODUCTION

Prostate bed radiotherapy (RT) is a major affecter of patients' long-term quality of life (QoL). To ensure the best possible outcome of these patients, dose constraints are key for optimal RT planning and delivery. However, establishing refined dose constraints requires access to patient-level data. Therefore, we aimed to provide such data on the relationship between OAR and gastrointestinal (GI) as well as genitourinary (GU) QoL outcomes of a homogenous patient cohort who received dose-intensified post-operative RT to the prostate bed. Furthermore, we aimed to conduct an exploratory analysis of the resulting data.

METHODS

Patients who were treated with prostate bed RT between 2010 and 2020 were inquired about their QoL based on the Expanded Prostate Cancer Index Composite (EPIC). Those (n = 99) who received volumetric arc therapy (VMAT) of at least 70 Gy to the prostate bed were included. Dose-volume histogram (DVH) parameters were gathered and correlated with the EPIC scores.

RESULTS

The median age at the time of prostate bed RT was 68.9 years, and patients were inquired about their QoL in the median 2.3 years after RT. The median pre-RT prostate-specific antigen (PSA) serum level was 0.35 ng/mL. The median duration between surgery and RT was 1.5 years. The median prescribed dose to the prostate bed was 72 Gy. A total of 61.6% received prostate bed RT only. For the bladder, the highest level of statistical correlation (p < 0.01) was seen for V10-20Gy, Dmean and Dmedian with urinary QoL. For bladder wall, the highest level of statistically significant correlation (p < 0.01) was seen for V5-25Gy, Dmean and Dmedian with urinary QoL. Penile bulb V70Gy was statistically significantly correlated with sexual QoL (p < 0.05). A larger rectal volume was significantly correlated with improved bowel QoL (p < 0.05). Sigmoid and urethral DVH parameters as well as the surgical approach were not statistically significantly correlated with QoL.

CONCLUSION

Specific dose constraints for bladder volumes receiving low doses seem desirable for the further optimization of prostate bed RT. This may be particularly relevant in the context of the aspiration of establishing focal RT of prostate cancer and its local recurrences. Our comprehensive dataset may aid future researchers in achieving these goals.

Hemorrhagic Cystitis: Making Rapid and Shrewd Clinical and Surgical Decisions for Improving Patient Outcomes

Hemorrhagic cystitis (HC) can be one of the most challenging clinical scenarios for urologists to manage. It most commonly occurs as a toxicity of pelvic radiation therapy or in patients treated with the oxazaphosphorine class of chemotherapy. Successful management of HC necessitates a stepwise approach with a thorough understanding of the various treatment options. Once ensuring hemodynamic stability, conservative management includes establishing bladder drainage, manual clot evacuation, and continuous bladder irrigation through a large-bore urethral catheter. If gross hematuria persists, operative cystoscopy with bladder clot evacuation is often required. There are multiple intravesical options for treating HC, including alum, aminocaproic acid, prostaglandins, silver nitrate, and formalin. Formalin is an intravesical option that has caustic effects on the bladder mucosa and is most often reserved as a last-line intravesical treatment. Non-intravesical management tools include hyperbaric oxygen therapy and oral pentosan polysulfate. If needed, nephrostomy tube placement or superselective angioembolization of the anterior division of the internal iliac artery can be performed. Finally, cystectomy with urinary diversion is a definitive, albeit invasive, treatment option for refractory HC. While there is no standardized algorithm, treatment modalities typically progress from less to more invasive. Clinical judgement and shared decision-making with the patient are required when choosing therapies for managing HC, as success rates are variable and some treatments may have significant or irreversible effects.

Symptom burden and health-related quality of life six months after hyperbaric oxygen therapy in cancer survivors with pelvic radiation injuries

PURPOSE

Late radiation tissue injuries (LRTIs) after treatment for pelvic cancer may impair health related quality of life (HRQoL). Hyperbaric oxygen therapy is an adjuvant therapy for LRTIs, but limited studied. The aim of this study was to explore the development and association between symptoms of LRTI and HRQoL following hyperbaric oxygen treatment.

METHODS

A pretest-posttest design was used to evaluate the changes in pelvic LRTIs and HRQoL from baseline (T1), immediately after treatment (T2) and at six-month follow-up (T3). EPIC and EORTC-QLQ-C30 were used to assess LRTIs and HRQoL. Changes were analysed with t-tests, and associations with Pearson's correlation and multiple regression analyses.

RESULTS

Ninety-five participants (mean age 65 years, 52.6% men) were included. Scores for urinary and bowel symptoms, overall HRQoL, all function scales and the symptoms scales sleep, diarrhoea, pain and fatigue were significantly improved six months after treatment (P-range = 0.00-0.04). Changes were present already at T2 and maintained or further improved to T3. Only a weak significant correlation between changes in symptoms and overall HRQoL was found (Pearson r-range 0.20-0.27).

CONCLUSION

The results indicate improvement of pelvic LRTIs and HRQoL following hyperbaric oxygen therapy, corresponding to minimal or moderate important changes. Cancer survivors with pelvic LRTIs and impaired HRQoL may benefit from undergoing hyperbaric oxygen therapy. Especially the reduced symptom-severity and improved social- and role function can influence daily living positively.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03570229. Released 2. May 2018.

Creation and validation of the harmonized Arabic version of the Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC-CP)

Objectives

Tocreate and validate a translated Arabic version of the Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC-CP), a validated patient-reported outcome (PRO) widely used for assessing the quality of life in patients with prostate cancer (PCa).

Patients and Methods

Using the established protocol as defined by the Professional Society for the Health Economics and Outcomes Research (ISPOR) for translating patient care questionnaires, a harmonised translated Arabic version of EPIC-CP was created. The questionnaire was tested in native Arabic speakers from four different Arabic countries (Saudi Arabia, United Arab Emirates, Jordan, and Kuwait). Cronbach’s alpha and interclass coefficient correlation (ICC) analyses were used to test the internal consistency and test–retest reliability, respectively. In addition, PCa characteristics were collected for participants.

Results

In total, 168 patients with PCa participated in the study (39 from Saudi Arabia, 23 from United Arab Emirates, 65 from Jordan, and 41 from Kuwait). In all, 52 (31%) participants repeated the questionnaire for test–retest reliability analysis. The median (interquartile range [IQR]) age of patients included in the study was 66 (61–71) years. The median (IQR) PSA level was 9.8 (6–19) ng/mL. Most patients had Grade Group 2 PCa at diagnosis (31%), clinical stage cT1 (42%), managed primarily by urology (79%), and the primary treatment was radical prostatectomy (71%). The total Cronbach’s alpha coefficient was 0.84 demonstrating an acceptable internal consistency. The total ICC was also acceptable at 0.64.

Conclusion

The Arabic version of the EPIC-CP is a reliable and valid tool for assessing health-related quality of life for Arabic patients with PCa.

Decision Regret and Quality of Life after Focal Therapy with Vascular-Targeted Photodynamic Therapy (TOOKAD®) for Localized Prostate Cancer

PURPOSE

The aim of the study was to assess quality of life (QoL), decision involvement, and decisional regret after treatment with vascular-targeted photodynamic therapy (VTP) (TOOKAD®) for unilateral low-risk prostate cancer.

METHODS

Validated questionnaires (EORTC QLQ-C30 and QLQ-PR25) capturing QoL post-treatment, involvement in decision-making (Control Preferences Scale) and decision regret (Decisional Regret Scale), were given to patients at the 12-month visit after undergoing VTP at our institution between May 2018 and February 2021.

RESULTS

Out of 44 patients, 36 patients were included in this study and 31 (86.1%) responded to the questionnaires. Mean overall health score capturing QoL at 12 months was 79.3 (standard deviation: ±18.1). 70.9% of the patients (n = 22) had no decision regret, and 67.8% of men (n = 21) had an active role in decision-making. In control biopsy at 12 months post-treatment, 19.4% of patients (n = 7) presented with local recurrence and progression to higher Gleason score (GS) was found in 13.8% of patients (n = 5). Patients (n = 3) presenting with tumor recurrence or progression to higher GS in control biopsy showed a significantly higher level of decision regret (p < 0.009).

CONCLUSION

Only 9.7% of men (n = 3) felt a strong emotion of regret at 12 months after VTP. Level of decision regret was significantly higher in patients with local recurrence or tumor progression detected in control biopsy. QoL was stable after VTP.

Standardising the Assessment of Patient-reported Outcome Measures in Localised Prostate Cancer. A Systematic Review

CONTEXT

Prostate cancer (PCa) is the second most common cancer among men worldwide. Urinary, bowel, and sexual function, as well as hormonal symptoms and health-related quality of life (HRQoL), were prioritised by patients and professionals as part of a core outcome set for localised PCa regardless of treatment type.

OBJECTIVE

To systematically review the measurement properties of patient-reported outcome measures (PROMs) used in localised PCa and recommend PROMs for use in routine practice and research settings.

EVIDENCE ACQUISITION

The psychometric properties of PROMs measuring functional and HRQoL domains used in randomised controlled trials including patients with localised PCa were assessed according to the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) methodology. MEDLINE and Embase were searched to identify publications evaluating psychometric properties of the PROMs. The characteristics and methodological quality of the studies included were extracted, tabulated, and assessed according to the COSMIN criteria.

EVIDENCE SYNTHESIS

Overall, 27 studies evaluating psychometric properties of the Expanded Prostate Cancer Index Composite (EPIC), University of California-Los Angeles Prostate Cancer Index (UCLA-PCI), European Organisation for Research and Treatment of Cancer (EORTC) quality of life core 30 (QLQ-C30) and prostate cancer 25 (QLQ-PR25) modules, International Index of Erectile Function (IIEF), and the 36-item (SF-36) and 12-item Short-Form health survey (SF-12) PROMs were identified and included in the systematic review. EPIC and EORTC QLQ-C30, a general module that assesses patients' physical, psychological, and social functions, were characterised by high internal consistency (Cronbach's α 0.46-0.96 and 0.68-0.94 respectively) but low content validity. EORTC QLQ-PR25, which is primarily designed to assess PCa-specific HRQoL, had moderate content validity and internal consistency (Cronbach's α 0.39-0.87). UCLA-PCI was characterised by moderate content validity and high internal consistency (Cronbach's α 0.21-0.94). However, it does not directly assess hormonal symptoms, whereas EORTC QLQ-PR25 does.

CONCLUSION

The tools with the best evidence for psychometric properties and feasibility for use in routine practice and research settings to assess PROMs in patients with localised PCa were EORTC QLQ-C30 and QLQ-PR25. Since EORTC QLQ-C30 is a general module that does not directly assess PCa-specific issues, it should be adopted in conjunction with the QLQ-PR25 module.

PATIENT SUMMARY

We reviewed and appraised the measurement properties of patient-reported outcome measure questionnaires used for patients with localised prostate cancer. We found good evidence to suggest that two questionnaires (EORTC QLQ-C30 and QLQ-PR25) can be used to measure urinary, bowel, and sexual functions and health-related quality of life.

Dose-volume histogram parameters and patient-reported EPIC-Bowel domain in prostate cancer proton therapy

Purpose

To analyze rectal dose and changes in quality of life (QOL) measured with the Expanded Prostate and Cancer Index Composite (EPIC) bowel domain in patients being treated for prostate cancer with curative-intent proton beam therapy (PBT) within a large single-institution prospective registry.

Materials and Methods

Data was collected from 243 patients with localized prostate cancer treated with PBT from 2016 to 2018. The EPIC survey was administered at baseline, end-of-treatment, 3, 6, and 12 months, then annually. Dose-volume histogram (DVH) parameters for the rectum were computed, and rectal dose was analyzed using BED (α/β = 3), EQD_2Gy, and total dose. Repeated measures mixed models were implemented to determine the effect of patient, clinical, and treatment factors (including DVH) on patient-reported bowel symptom burden (EPIC-Bowel).

Results

Treatment overall resulted in changes in EPIC-Bowel scores (baseline score = 93.7), most notably at end-of-treatment (90.6) and 12 months (89.7). However, they returned to baseline at 36 months (92.9). On multivariate modeling, rectal BED D₂₅ (Gy) ≥23% was significantly associated with decline in QOL scores measuring bother (p < 0.01; 4.06 points different).

Conclusion

Rectal doses, specifically BED D₂₅ (Gy) ≥23%, are significantly associated with decline in bowel bother-related QOL in patients undergoing definitive radiotherapy for localized prostate cancer. This study demonstrates BED as an independent predictor of bowel QOL across dose fractionations of PBT.

Health-related quality of life in men with localized prostate cancer treated with radiotherapy: validation of an abbreviated version of the Expanded Prostate Cancer Index Composite for Clinical Practice in Spain

Background

Health-related quality of life (HRQoL) is greatly affected by prostate cancer (PCa) and associated treatments. This study aimed to measure the impact of radiotherapy on HRQoL and to further validate the Spanish version of the 16-item Expanded Prostate Cancer Index Composite (EPIC-16) in routine clinical practice.

Methods

An observational, non-interventional, multicenter study was conducted in Spain with localized PCa patients initiating treatment with external beam radiotherapy (EBRT) or brachytherapy (BQT). Changes from baseline in EPIC-16, University of California-Los Angeles Prostate Cancer Index (UCLA-PCI), and patient-perceived health status were longitudinally assessed at end of radiotherapy (V2) and 90 days thereafter (V3). Psychometric evaluations of the Spanish EPIC-16 were conducted.

Results

Of 516 patients enrolled, 495 were included in the analysis (EBRT, n = 361; BQT, n = 134). At baseline, mean (standard deviation [SD]) EPIC-16 global scores were 11.9 (7.5) and 10.3 (7.7) for EBRT and BQT patients, respectively; scores increased, i.e., HRQoL worsened, from baseline, by mean (SD) of 6.8 (7.6) at V2 and 2.4 (7.4) at V3 for EBRT and 4.2 (7.6) and 3.9 (8.2) for BQT patients. Changes in Spanish EPIC-16 domains correlated well with urinary, bowel, and sexual UCLA-PCI domains. EPIC-16 showed good internal consistency (Cronbach’s alpha = .84), reliability, and construct validity.

Conclusion

The Spanish EPIC-16 questionnaire demonstrated sensitivity, strong discriminative properties and reliability, and validity for use in clinical practice. EPIC-16 scores worsened after radiotherapy in different HRQoL domains; however, a strong tendency towards recovery was seen at the 3-month follow-up visit.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12955-021-01856-z.

Comparative Effectiveness Research in Localized Prostate Cancer: A 10-Year Follow-up Cohort Study

PURPOSE

Long-term comparative effectiveness research on localized prostate cancer treatments is scarce, and evidence is lacking especially for brachytherapy. The aim of this study was to assess the long-term impact of the side effects of radical prostatectomy, brachytherapy, and external radiation therapy on patients with localized prostate cancer at 10 years, using propensity score analyses.

METHODS AND MATERIALS

This was a prospective observational study of a cohort of men who received a diagnosis of clinically localized prostate cancer (clinical stage T1 or T2, low and intermediate risk group) and were treated with radical prostatectomy (n = 139), brachytherapy (n = 317), or external radiation therapy (n = 194). Treatment decisions were jointly made by patients and physicians. Patient-reported outcome (PRO) evaluation included the Expanded Prostate Cancer Index Composite and Short Form-36, administered centrally by telephone interviews before and annually after treatment. The Expanded Prostate Cancer Index Composite covers urinary, bowel, sexual, and hormonal domains. To assess PRO changes over time, while accounting for correlation among repeated measures, generalized estimating equation models adjusted by propensity scores were constructed.

RESULTS

The PRO completion rate at 10 years was 85.8%. Generalized estimating equation models showed that the pattern of radical prostatectomy side effects, with substantial urinary incontinence and sexual dysfunction, remained until 10 years after treatment (standard deviation [SD], -1.1 and -1.3, respectively). Brachytherapy produced late deterioration in urinary continence (SD, -0.4) and sexual function (SD, -0.9) that appeared midterm, but the differences from radical prostatectomy remained statistically significant at 10 years (P < .001 after adjusting by propensity score). External radiation therapy showed similar results to brachytherapy, but with bowel bother (SD, -0.3).

CONCLUSIONS

Although late deterioration in radiation therapy groups attenuated differences from radical prostatectomy, relevant PRO differences still remained after 10 years. Our findings support that brachytherapy is the treatment option that causes the least impact on PROs; it is therefore an alternative to be considered when making evidence-based decisions on localized prostate cancer treatment.

Measuring Quality of Life Following Robot-Assisted Radical Prostatectomy

BACKGROUND

Prostate cancer (PCa) represents the most common solid organ malignancy in men. Fortunately, at the time of diagnosis, the majority of cases are staged as localized or regional disease, conferring excellent 5- and 10-year cure rates. There are several first line treatment options including surgical approaches such as robot-assisted radical prostatectomy (RARP) and radiation therapy (RT) available to patients with localized disease that offer similar PCa oncologic outcomes but are associated with potentially significant side effects which may impact health-related quality of life (HRQOL) domains. Recently, clinicians and investigators have sought to better understand these changes in HRQOL metrics with the utilization of patient-reported outcomes (PRO). Given that RARP represents the most common surgical treatment for PCa in the United States, there has been a particular interest in assessing these outcomes derived by patient perspectives to more fully appreciate treatment-related impact on quality of life following RARP.

OBJECTIVE

This narrative review sought to explore the instruments available to measure quality of life after RARP, a review of the PRO data after RARP, and future directions for assessing and improving quality of life outcomes following this surgery.

CLINICAL USE

There are several treatment options for men diagnosed with local and regional prostate cancer with similar oncologic outcomes but differing patterns of side effects affecting post-treatment quality of life. Understanding data reported directly by patients following RARP about their side effects and quality of life gives providers additional information for appropriate preoperative counseling for patients choosing between treatment options for their prostate cancer.

Psychometric validation of the German version of the EPIC-26 questionnaire for patients with localized and locally advanced prostate cancer

PURPOSE

For patients with prostate cancer, validated and reliable instruments are essential for measuring patient-reported outcomes. The aim of this study was to validate the German version of the widely established Expanded Prostate Cancer Index Composite with 26 items (EPIC-26).

METHODS

A German translation of the original questionnaire was tested in 3094 patients with localized or locally advanced (any T, any N and M0) prostate cancer with treatment intent (including radical prostatectomy, brachytherapy, active surveillance, watchful waiting). They completed the EPIC-26 questionnaire before treatment. A total of 521 of them also completed a questionnaire 12 months afterward. Internal consistency, sensitivity to change, and construct validity were assessed.

RESULTS

The internal consistency of all domains was sufficient (Cronbach's alpha between 0.64 and 0.93). Item-to-scale correlation coefficients showed acceptable associations between items and their domain score (all > 0.30), with the lowest scores for "bloody stools" (r = 0.37) and "breast problems" (r = 0.32). Confirmatory and exploratory factor analysis confirmed the five-dimension structure of the EPIC-26 (comparative fit index 0.95).

CONCLUSIONS

Psychometric evaluation suggests that the German version of the EPIC-26 is a well-constructed instrument for measuring patient-reported health-related symptoms in patients with prostate cancer.

Validation of the Italian version of the abbreviated expanded prostate Cancer index composite (EPIC-26) in men with prostate Cancer

Background

This study aims to validate and evaluate the psychometric properties and reliability of the Italian version of the Expanded Prostate Cancer Index Composite – Short Form (EPIC-26), a measure of quality of life (QoL) for prostate cancer patients.

Methods

Two hundred and eighty-four prostate cancer patients completed the Italian version of the EPIC-26 questionnaire at 45 days (T1) and 3 months (T2) after robot-assisted radical prostatectomy (RARP). Psychometric properties were evaluated using structural equation modeling: the goodness of fit of the correlated five-factor model (CFFM) for the EPIC-26 was assessed using the confirmatory factor analysis (CFA), while longitudinal invariance was conducted to assess the ability of the EPIC-26 to measure QoL construct over time. Test-retest reliability was assessed as well by considering intraclass correlations.

Results

At T1, the CFFM model displayed a good fit to data. Similarly, the model showed an adequate fit also at T2. Results of the reliability analysis attested the acceptable internal consistency and test-retest reliability of each dimension: all Cronbach’s alphas could be classified as acceptable (i.e., above .65) except for low Cronbach’s alpha for hormonal dysfunction at T1 (i.e., .638) and urinary irritation at both waves. (i.e., respectively .585 and .518). Finally, psychometric properties were invariant over time and each of the five dimensions of QoL displayed from moderate (all ICCs above .500) to good test-retest reliability (i.e. ICC for urinary incontinence = .764).

Conclusions

Results of the CFA and the measurement invariance analysis demonstrated the validity of the Italian version of the EPIC-26 to assess QoL in prostate cancer patients. Its reliability and good psychometric qualities are well-supported, thus providing a valid tool to assess health-related quality of life and its change over time in prostate cancer patients.

Development and Validation of Crosswalks for Patient-reported Sexual and Urinary Outcomes Between Commonly Used Instruments

BACKGROUND

Patient-reported outcome measures (PROMs) have become widely adopted in the care of patients with prostate cancer, but there is no validated crosswalk between two commonly used instruments, the Expanded Prostate Cancer Index Composite Short Form (EPIC-26) and the Memorial Sloan Kettering (MSK) instrument, which consists of the International Index of Erectile Function-6 (IIEF-6) questionnaire and the MSK radical prostatectomy urinary outcome scale.

OBJECTIVE

To develop and validate bidirectional crosswalks between the sexual and urinary domains (single domain in MSK, separate incontinence and irritative/obstructive domains in EPIC-26) of the MSK and EPIC-26 instruments.

DESIGN, SETTING, AND PARTICIPANTS

Radical prostatectomy (RP) patients completing instruments at MSK and Michigan Urological Surgery Improvement Collaborative (MUSIC) between January and May of 2017 were invited to enroll. Stratified random sampling (by institution, MSK urinary function score, and MSK erectile function score) was used to divide patient data into training and test sets. Models were developed to predict the domain score for each instrument using the other's item responses and domain scores. Performance was evaluated using capped root-mean-squared error and accuracy at established thresholds.

RESULTS AND LIMITATIONS

We received 517 instruments at MSK and 1033 within MUSIC, which were assigned to training (825), post-RP test (412), and pre-RP test (313) sets. We found the crosswalks to have low error and high accuracy. Although the crosswalks are more accurate if responses to each item are known, it is possible to convert between instruments on the basis of a total domain score.

CONCLUSIONS

The crosswalks are a valid way to convert between sexual and urinary domains of the MSK and EPIC-26 instruments.

PATIENT SUMMARY

We developed and validated a set of formulas that allow conversion of sexual and urinary function scores between the Memorial Sloan Kettering and Expanded Prostate Cancer Index Composite Short Form patient-reported outcome questionnaires. These crosswalks allow seamless transition between the two questionnaires.