Introduction

The incidence of cancer is increasing in Hong Kong at an average annual rate of 3.9% [1]. Because of advances in cancer treatment and therapies over recent decades, many cancer patients are now living longer lives. “Cancer survivor” is a term used to describe those cancer patients who have completed treatment for the disease [2]. There are many definitions to specify the different periods of survivorship. Miller et al. proposed a model they called “seasons of survivorship”, which consisted of four seasons in the cancer trajectory: acute survivorship, transitional survivorship, extended survivorship, and permanent survival [3]. Transitional survivorship is the period of time spent passing from active treatment to watchful waiting and maintenance therapy. Cancer survivors are closely monitored during this period for any sign of progression in the disease. In this study, we define transitional survivorship as the period from 1 to 5 years after the completion of curative active cancer treatment, since in the local context cancer patients are followed up for 5 years to check for any recurrence.

Within the period of transitional survivorship, cancer survivors have to adapt to the changes in their physical, psychological, sexual, and social lives resulting from the disease and its treatment [3]. Although cancer survivors may experience different side effects in variable levels, many of them report to have adverse changes in multiple aspects of quality of life (QOL), and such changes may remain with them throughout the rest of their lives [4]. Impact of different diseases and health status on QOL is regarded as health-related quality of life (HRQOL) [5].

Sexual function is one of the important aspects of QOL, but it is largely disrupted after the diagnosis of cancer and its related treatment [6]. Adverse changes in sexual function may be associated with problems in all areas of QOL—physical symptoms, emotional disturbances, self-esteem, self-perception, sense of well-being, satisfaction with life, relationships with partners, and other social relationships [7]. Sexual dysfunction resulting from cancer and its treatment therefore has negative impacts on HRQOL. Previous studies have found that cancer patients are at higher risk of impaired sexual function [8]. As a result, a great deal of the literature has focused on the sexual function and HRQOL of these individuals following their diagnosis, treatment, and recovery from cancer. However, there is no Chinese version of tools for assessing HRQOL and male sexual function for survivors in transitional cancer survivorship. In fact, Chinese cancer survivors may experience substantial stress on sexuality as traditional Chinese culture emphasizes the continuation of one’s family line [9]. This study aims to translate and develop psychometrically sound and culturally appropriate tools for assessing HRQOL and male sexual function in Chinese cancer survivors.

During this period, after resumption of their sex life, many patients are found to have a greater degree of sexual dysfunction than the normal population because of the physiological and psychological changes resulting from the disease and treatment received. Both male and female cancer survivors suffer from sexual dysfunction, but the problems encountered vary. Male cancer survivors reported suffering from erectile and ejaculation problems, while female survivors experienced vaginal dryness and pain during sexual intercourse resulting in sexual dissatisfaction [10]. Some of them were hesitant to resume sex, and more than half of Asian women completely refrained from having sexual activity because of the sexual dysfunction [11]. Treatment modalities are factors associated with the degree of sexual dysfunction. A population-based study has indicated that pre-operative radiotherapy is a significant cause of greater sexual dysfunction in cancer survivors than in those receiving surgery alone [12]. On the other hand, much of the extant literature focuses on the investigation of sexual function in patients with prostate, breast, or gynecological cancers [13–16]. Yet, there are few studies, if any, examining sexual issue among those surviving other types of cancers. For example, survivors of bladder cancer and Hodgkin’s disease also experience difficulty in sexual function, but they are understudied. Moreover, many of the relevant studies pertaining to survivors’ sexual function so far reported are based on Western samples. As mentioned, traditional Chinese culture places a high value on parenting and the continuation of one’s family line [9], and the impact of sexual problems on HRQOL could therefore be even more substantial among Chinese adult cancer survivors.

Chinese sexual tools for female cancer survivors are available, including Sexual Function After Gynecologic Illness Scale (SFAGIS) and Sexual Function-Vaginal Changes Questionnaire (SVQ) which have been developed and validated in Hong Kong Chinese population [17, 18]. The Chinese SFAGIS was specifically designed for gynecological cancer, and the Chinese SVQ can be applied in all types of cancer to assess sexual function among female cancer survivors. However, there is a lack of such tools with good psychometric properties for male cancer survivors. One available Chinese male generic sexual tool is the International Index of Erectile Function (IIEF) which is a 15-item generic instrument for measuring changes in sexual function. It has been found to be a reliable and valid instrument with a high degree of sensitivity and specificity in detecting erectile dysfunction [19]. As the IIEF is relatively lengthy and not suitable for busy clinical settings, a simplified version (IIEF-5) has been established by retaining five items with a moderate or good discrimination ability to identify the presence or absence of erectile dysfunction. However, the IIEF-5 has not been validated and is not cancer-specific [20]. Another male sexual tool, the Expanded Prostate Cancer Index Composite (EPIC) sexual domain, has not been translated into Chinese. The sexual domain comprises 13 items; nine of which assess sexual function and four the degree of bothersome caused by the sexual problems [21]. Although the EPIC was originally designed for prostate cancer patients, the sexual domain was found to be correlated highly with IIEF-5 but to provide more detailed information on sexual function in men and able to detect a lesser degree of impairment than IIEF-5 [22]. The EPIC sexual domain may be therefore applicable to patients suffering from other cancer types and better able to identify sexual dysfunction.

As for the assessment of HRQOL, multiple instruments with Chinese versions have been used, such as the Functional Assessment of Cancer Therapy-General Scale (FACT-G) and European Organization for Research and Treatment of Cancer (EORTC). These scales were developed to evaluate the acute effects of being newly diagnosed with cancer and after treatment, so may not be appropriate for cancer survivorship. Quality of Life in Adult Cancer Survivors (QLACS) is a validated tool designed to capture the prolonged effects of cancer and its related treatment on cancer survivors, including pain, fatigue, sexual problems, body image disturbance, psychological distress, financial issues, concerns over family and worries about recurrence, and the common problems and concerns encountered by cancer patients after the completion of curative active treatment. The QLACS comprises 47 items clustered into 12 domains: seven generic and five cancer specific [23]. It has been applied in transitional cancer survivors with good psychometric properties. The QLACS is regarded as a reliable and valid instrument for assessing HRQOL among patients with different cancer sites transitioning from active treatment [24, 25].

In view of the lack of validated Chinese tools for assessing HRQOL and male sexual function among cancer survivors, this study aims to translate and adapt the QLACS and EPIC sexual domain into Chinese (Cantonese) and to establish their psychometric properties in Hong Kong Chinese cancer survivors.

Methods

Instruments

The QLACS is an instrument developed for assessing HRQOL in long-term cancer survivors (≥5 years). There are 47 items grouped into 12 domains: seven generic (negative feelings, positive feelings, cognitive problems, sexual problems, physical pain, fatigue, and social avoidance), and five cancer specific (appearance concerns, financial problems, distress-recurrence, distress-family, and benefits). Each item is rated on a 7-point Likert scale ranging from “1 = never” to “7 = always” with respect to the past 4 weeks. For all domains except positive feelings and benefits of having cancer, higher scores indicate more problems or poorer HRQOL [23]. Two summary scores, generic and cancer-specific, and 12 domain scores can be calculated. The QLACS has been tested in transitional cancer survivors with good psychometric properties [24, 25].

The EPIC sexual domain is a subscale of a comprehensive instrument, EPIC, designed to evaluate a male patient’s life and functions following prostate cancer treatment [21]. There are 13 items in the EPIC sexual domain assessing issues concerned with sexual function that appears to be relevant to male patients with other cancer diagnoses. Nine items measure sexual function and four evaluate the degree of bothersome caused by the dysfunction. Subscale and summary scores can be calculated with a maximum weighted score of 100. Higher scores indicate better sexual function. This scale has established psychometric properties in prior work [21].

Translation and cross-cultural adaptation

The Brislin model of translation was used to guide the QLACS and EPIC sexual domain translation [26]. The first step was forward and backward translations on the original version of the scales. The original QLACS and EPIC sexual domain were translated into Chinese (Cantonese) by a bilingual native registered nurse, and then reviewed by a monolingual reviewer for incomprehensible or ambiguous wording. Back translation was performed by another bilingual translator who was “blinded” to the original version to translate the Chinese (Cantonese) version into English. Lastly, the research team checked for linguistic congruence and cultural relevancy of the back-translated version by comparing it to the original English version. Amendment was made on the items which had apparent discrepancies to achieve a maximum equivalent version.

In addition, adaptation process is suggested to be conducted for instruments which are to be used across cultures in order to attain a semantic, idiomatric, experiential, and conceptual equivalent version for local culture use [27]. The guidelines for cross-cultural adaption of scales by Beaton, Bombardier, Guillemin, and Ferraz were considered in the translation process of the QLACS and EPIC sexual domain, specifically experiential equivalence between items in a different culture [27].

The final Chinese (Cantonese) version of QLACS (QLACS-C) and EPIC (EPIC-C) sexual domain was subjected to semantic equivalence and content validity tests by an expert panel, and also disseminated to two cancer survivors for assessing whether the translated version was understandable, relevant, and comprehensive to measure HRQOL and male sexual function.

Reliability

The reliability of the QLACS-C and EPIC-C sexual domain was assessed by testing their internal consistency and test-retest reliability. As sexual function and HRQOL are relatively stable outcomes in cancer survivors, test-retest reliability was assessed for the first 50 recruited participants in the study with a time interval of 2 weeks.

Recruitment process

The sample for the study was drawn from patients attending follow-up at the oncology out-patient clinic at an acute hospital in Hong Kong. Inclusion criteria for subject recruitment included the following: a history of cancer of any types, age above 18 at the time of diagnosis, completed all curative active cancer treatment within the last 1 to 5 years, able to read Chinese and communicate in Cantonese, and with no known psychiatric illness.

All eligible participants were approached and invited to join the study. The study aims were explained, with information sheets, and consent forms were distributed. After written consent is obtained, demographic data was collected, and the instruments were distributed for self-administration. For those participants who had low literacy level, the data was gathered in face-to-face interviews. The first 50 participants (male and female) to be recruited were contacted via telephone at a 2-week interval to collect data on the QLACS-C, and the first 50 male subjects was reassessed by means of the EPIC-C sexual domain for test-retest reliability.

Validity

The validity of the QLACS-C and EPIC-C sexual domain was assessed by conducting factor analysis and testing their divergent and convergent validities. Confirmatory factor analysis was conducted to verify the 12-factor structure of the QLACS-C and two-factor structure of the EPIC-C sexual domain. Goodness-of-fit criteria, including the chi-square statistic to degree of freedom ratio (χ2/df) ≤3.00, root mean square error of approximation (RMSEA) <0.08, standardized root mean square residua adjusted (SRMS) <0.08, comparative fit index (CFI) ≥0.90, and non-normed fit index (NNFI) ≥0.90 were used to determine the overall data-model fitness [28]. The physical well-being subscale of the Traditional Chinese version of the Functional Assessment of Cancer Therapy-General (TCHI FACT-G) version 4 was used to perform divergent validity with the EPIC sexual domain. The TCHI FACT-G version 4 and IIEF were adopted to test the convergent validity of the QLACS-C and EPIC-C sexual domain, respectively.

Ethics

Ethical approval was obtained from the Ethics Committee, Faculty of Medicine, the Chinese University of Hong Kong. Where patient samples were recruited, further ethical approval was sought and obtained from the participating hospital.

Results

Sample

A convenience sample of 289 Hong Kong Chinese cancer survivors was recruited. It included 70 males and 219 females, mainly diagnosed with cancers in female breast and genital organs (n = 166), lip, oral cavity and pharynx (n = 46), and digestive organs (n = 33). The age of the participants ranged from 21 to 83 with a mean of 53.5, and majority of them were married (71%). Most participants had stages I or II cancer (55%), and the major type of treatment received was surgery plus chemotherapy and radiotherapy (20%), followed by chemotherapy plus radiotherapy (10%), surgery alone (10%), or surgery plus radiotherapy (10%). More than half of the participants had completed treatment for 1 to 3 years (59%). The demographic and clinical data of the participants is presented in Table 1.

Table 1 The demographic and clinical data of the participants (n = 289)
Full size table

Cross-cultural adaptation, semantic equivalence, and content validity

A panel of six oncology-specialized health care professionals was invited to rate semantic equivalence between the each item of the original English and the final version of QLACS-C and EPIC-C sexual domain independently. The cultural relevance and representativeness of the items to measure HRQOL and male sexual function of cancer survivors were also assessed. A content validity index (CVI) with a 4-point Likert scale was used (1 = not appropriate/relevant, 2 = somewhat appropriate/relevant, 3 = quite appropriate/relevant. 4 = most appropriate/relevant). All items in the QLACS-C achieved a CVI of 0.83 to 1.0 for semantic equivalence and content validity, while for the EPIC-C sexual domain, all items had a CVI of 1.0 both for semantic equivalence and content validity. Therefore, the QLACS-C and EPIC-C sexual domain were considered to be a semantically equivalent and content valid instrument.

Two female and two male cancer survivors were recruited to assess whether the QLACS-C and EPIC-C sexual domain were understandable. Moreover, they were asked to comment on the relevance, importance, and comprehensiveness of the instrument content. All survivors reported that the items were easily understandable, culturally acceptable, without any ambiguous and embarrassment wording. No modification was made to the QLACS-C and EPIC-C sexual domain.

Internal consistency

Internal consistency was high for the QLACS-C with a Cronbach’s alpha of 0.96 for generic summary scale and 0.83 for cancer-specific summary scale. Cronbach’s alpha for the subscales ranged from 0.76 (sexual function) to 0.92 (physical pain) in the generic domains, and 0.71 (appearance concerns) to 0.89 (distress-recurrence) in the cancer-specific domains. For the EPIC-C sexual domain, the internal consistency of the overall scale was also high, with a Cronbach’s alpha of 0.96. Cronbach’s alphas for the function subscale and bother subscale were 0.96 and 0.93, respectively. This indicated the high reliability of both scales.

Test-retest reliability

The test-retest reliabilities for the QLACS-C and EPIC-C sexual domain with the 2-week interval were also satisfactory. Intra-class correlation coefficients of the generic and cancer-specific summary scales of the QLACS-C were 0.79 and 0.82, respectively. For the EPIC-C sexual domain, intra-class coefficients of the overall scale was 0.82, and that of the function and bother subscales were 0.85 and 0.71, respectively.

Convergent and divergent validity

Convergent validity of the QLACS-C was tested by correlating it with the Chinese version of TCHI FACT-G version 4. The Pearson product moment correlation found strong correlations between these two scales (r = 0.77 for generic summary scale; r = 0.57 for cancer-specific summary scale), indicating that the QLACS-C measures the same or has a similar construct as the TCHI FACT-G.

Convergent and divergent validities of the EPIC-C sexual domain was assessed by correlating it with the Chinese version of IIEF and the physical well-being subscale of TCHI FACT-G version 4. The Pearson product moment correlation found strong correlations between the EPIC-C sexual domain and the IIEF (r = 0.67 for the total score, r = 0.64 for function subscale, r = 0.60 for bother subscale), indicating that these two scales measures the same or has a similar construct. Conversely, the Pearson product moment correlation found weak correlations between the EPIC-C sexual domain and the physical well-being subscale of TCHI FACT-G version 4 (r = 0.11 for the total score, r = 0.09 for function subscale, r = 0.14 for bother subscale), indicating that these two scales measures different constructs.

Factor analysis

The results of confirmatory factor analysis supported the 12-factor structure of the QLACS-C in the Chinese population. The data model fit was supported with χ2/df = 1.34, RMSEA = 0.04, SRMS = 0.065, CFI = 0.99, and NNFI = 0.99. For the factorial validity of the EPIC-C sexual domain, its two-factor structure was mostly supported, with χ2/df = 1.79, SRMS = 0.078, CFI = 0.98, and NNFI = 0.98. However, the fit statistic of RMSEA was 0.109 above the criterion level of 0.08.

Discussion

The main purpose of the study was to translate and develop psychometrically sound and culturally appropriate tools for assessing HRQOL and male sexual function in Hong Kong Chinese cancer survivors. Our findings support that the QLACS-C and EPIC-C sexual domain are reliable and valid scales for collecting empirical information about Chinese cancer survivors’ HRQOL and male sexual function in a clinical setting. Moreover, the scales were found to be equivalent to the original English version in terms of their relevancy and representativeness to measure HRQOL and male sexual function among Chinese cancer survivors.

Furthermore, our study contributes to the HRQOL and male sexual function instrument development literature. A large sample of 289 participants (70 of them were male participants) was employed for the instrument translation and validation. This establishes the psychometric properties of QLACS-C and EPIC-C sexual domain and supports their uses in Chinese population.

Sexual function is considered to be a culturally sensitive topic, and it is not routinely assessed in clinical settings in Hong Kong. Chinese sexual tools for female cancer survivors have been developed and validated by the research team [17, 18], and male sexual function scale is now developed. Using the EPIC-C sexual domain can yield incremental information related to sexual function of male cancer survivors, so that those with sexual problems can be identified and referred for appropriate counseling and provided with intervention.

Negative changes in physical, psychological, sexual, and social lives resulting from cancer and its treatment may be profound and prolonged. Using the QLACS-C can capture the prolonged impacts of the disease and its related treatment on cancer survivors, including pain, fatigue, sexual problems, body image disturbance, psychological distress, financial issues, concerns over family and worries about recurrence, the common problems, and concerns after the completion of curative active treatment. Hence, appropriate interventions and counseling targeting improvement in the various aspects of QOL can be developed and provided to those high risk group of cancer survivors, and ultimately improve their HRQOL.

At the time of the validation process, confirmatory factor analysis supported the hypothesized 12-factor structure of the QLACS-C in Chinese cancer survivors. However, the two-factor structure of the EPIC-C sexual domain was partially supported. Previous literature indicated that the conceptualization of HRQOL varies across cultures. Culture influences the definition and dimensions of HRQOL [29]. Cultural context was also found to be relevant to sexual function. Attitudes to sexual activity, sexual behavior, and report of sexual dysfunction were influenced by cultural values [30]. As a result, development of culturally appropriate instrument is an important endeavor [29, 30]. Cross-cultural adaptation is an essential process in instrument translation and validation [31]. Confirmatory factor analysis indicated that the QLACS-C is a cross-culturally valid instrument for assessing HRQOL. For the EPIC-C sexual domain, fair goodness-of-fit index might be due to small sample size, 70 male participants, which limited the credibility of the results. The EPIC-C sexual domain should also be adopted in larger sample of male cancer survivors for retesting in future study. In the current study, the expert panel and male participants reported that the EPIC-C sexual domain was culturally acceptable.

The majority of the participants were middle-aged women with diagnosis of breast and gynecological cancer. The results of the study could not be generalized to the whole population of cancer survivors. Further testing of the QLACS-C which involves males and females with diversified clinical and demographic backgrounds are recommended.

Conclusions

We have translated and validated the Chinese (Cantonese) version of QLACS and EPIC sexual domain from its original English version. Our study shows that the scales are well understood and accepted by Chinese cancer survivors in a clinical setting, with good reliability and validity. The development of such psychometrically sound and culturally appropriate scales for assessing HRQOL and male sexual function in Hong Kong Chinese cancer survivors will advance our understanding of transitional cancer survivorship in Hong Kong and provide guidance for the development of cancer care services in the sexual area. The QLACS-C and EPIC-C sexual domain can be adopted in overseas countries with Chinese population in order to provide culturally sensitive cancer care. Besides, sexuality issue among all types of cancer survivors especially those who are understudied should be explored and investigated so that we can provide appropriate sexual care to support them as they adapt to changes in sexuality after diagnosis and treatment.

Relevancy to clinical practice

The QLACS-C and EPIC-C sexual domain can be used in clinical practice and research to assess HRQOL and male sexual problems in Chinese cancer survivors. Hence, appropriate interventions and counseling targeting improvement in the sexual function can be developed and provided to those high risk group of cancer survivors, and ultimately improve their HRQOL.