Background
Every year in Germany about 15,000 people between the ages of 15 to 39 are diagnosed with cancer, compromising about 3% of all new cases. The 5-year survival rate in this group is presently approximately 80% [
1]. According to the National Comprehensive Cancer Network definition (NCCN) [
2] this age group is referred to as “adolescent and young adults” (AYA), although the exact ages represented in this field of research vary greatly.
AYAs represent a specific age group, which, in medical and psycho-social regards, is distinct from children and middle-aged as well as older adult (40+) cancer patients. They are at a time in life characterised by unique and complex physical, cognitive, and psycho-social developmental tasks [
3]. Having cancer presents the affected person with many changes and challenges that collide with their current developmental tasks. The disease can decelerate their development and result in their original goals having to be discarded in the short term or long-term. In a recent systematic review by Quinn et al. [
4] about QoL in AYA cancer patients, nearly 35 studies concluded, that AYA cancer survivors are more likely to have poorer QoL compared with the age-matched general population and older cancer survivors.
Consequences of the disease and its treatment might lead to prolonged or new dependency on parents or a lengthy interruption of education, training, or professional life and financial problems. People in this age group are doubly burdened by the challenging but ordinary developmental tasks every young person faces and the difficulties of coping with a life-threatening illness [
5]. Thus, the time after treatment is often the most difficult phase of the disease because survivors have to simultaneously pursue their personal goals while also overcoming long-term consequences of their illness such as, for example, infertility caused by chemotherapy, fears of recurrence, and so on [
6‐
8].
In the AYA-HOPE survey [
9], 35% of all patients indicated at least one unsatisfied support need (e.g. psychological counselling or pain management) and more than 50% of the 524 AYAs surveyed had information needs concerning the long-term effects of the disease which were not addressed during the course of their treatment [
10]. Galan and colleagues [
11] identified some areas of need shared by both younger and older cancer patients; however they also found others that were specific to AYA cancer patients, such as fertility, sexual health, health behaviour, social support, and relationships with their peers. The lack of information about psychological support services was found to be associated with lower quality of life [
12,
13]. This lack of information can significantly affect patients’ quality of life even several years after they have finished treatment [
12,
14,
15]. Little data exists on AYA cancer survivors’ quality of life. This is due to the fact that the focus of prior studies has been on quality of life issues affecting the older cancer patient, and to the fact that adequate assessment instruments had not been developed to replicate quality of life in the context of a cancer disease specifically for this age group [
4,
13]. Quality of life is, however, of central importance to the development of targeted group-specific support services and the assessment of their effectiveness. Such services could address issues like vocational rehabilitation or dealing with limited physical (e.g. fertility, sexuality) or cognitive functions [
4,
8,
10].
Numerous instruments have been developed to measure health-related quality of life in cancer patients; however, we agree with other colleagues that they are often not suitable for the assessment of age-specific issues in young adult cancer patients [
16‐
18]. Studies on quality of life in AYAs previously used non-specific assessment tools, such as the SF-36 or the EORTC QLQ-C30, which are limited to general dimensions of quality of life and do not account for age-specific issues such as fertility, body-image, or employment challenges [
19‐
21]. Crystal Park and colleagues have therefore developed the Late Adolescence and Young Adulthood Survivorship-related Quality of Life measure (LAYA-SRQL) with a view to understanding the needs of AYAs vis-à-a their unique place in the life course and improving both medical and psychosocial care in a targeted manner [
22]. Clearly defined treatment consequences and efficient screening would help to facilitate the provision of interdisciplinary care. To the best of our knowledge, there are currently no validated standard instruments in Germany for evaluating health-related quality of life in young adult cancer patients and no other quality of life measurements for young cancer patients has been developed in Germany. Considering that German is the most spoken native language in the European Union [
23], there is a need for a validated tool measuring quality of life German-speaking patients aged 15 and 39 years.
The aim of the present study was to formally translate and cross-culturally adapt the German version of the LAYA-SRQL on a sample of outpatient AYA cancer patients and to test the German version for psychometric properties in terms of its reliability and validity.
Discussion
In order to ascertain the support needs of the AYA-group and to reduce the long-term impact of cancer on this population, there is an urgent need for a target group-specific, valid, and practical assessment tool that can be implemented within the context of follow-up care. The LAYA-SRQL is a valid and reliable questionnaire for assessing relevant quality of life domains among adolescent and young adult cancer survivors. So far, there has not been an equivalent instrument within the German-speaking countries. Therefore, the presented study aimed to describe the translation and validation of the age-specific LAYA-SRQL.
The data supported the reliability and validity of the German version as well as the replication of the 10-factorial structure of the original questionnaire in our sample.
Internal consistencies of all eight subscales demonstrated good reliability with Cronbach’s alpha >0.7 and also CR > 0.7. In contrast to the original scales, internal consistencies in the German version were lower except for the “Education” and “Health Care” dimensions. As already described in the original LAYA-SRQL, the German sample reported being most satisfied with “Relationship” and “Education”. The dimension of “Health Care” showed better means in the German sample. This may be due to the differences between the German and the American health care system. Participants in both samples were most dissatisfied with issues encompassed by the “Fertility”, “Intimacy”, and “Cognition” dimensions, a finding that has emerged in previous studies as well [
14,
29]. Our results show that the German LAYA-SRQL strongly correlated with the SF-12v2 tool for measuring health-related quality of life, which confirmed the convergent validity of the scale.
Along with the value of these results, this study does have some limitations. Due to the cross-sectional study design we were not able to measure test-retest reliability. Further studies should examine this issue.
Furthermore, we could not conduct non-responder analyses because of the different ways participants could access the study and the fact that the cooperating hospitals did not document their recruitment efforts in detail. Strengths of the study include its sample size since the AYAs were difficult to recruit and the low rate of missing values for conducting confirmatory factor analysis.
Additionally, the high number of “not applicable” answers of the dimension “Spirituality” has to be considered in future research. This fact might have its roots in a cultural pattern; thus, the cultural environment must be considered when measuring spirituality [
30]. Spirituality (according to a broader concept of religion) has a higher level of importance in the USA than in Germany [
31]. Cross-cultural research between the USA and Germany revealed that self-identifying as being “spiritual” or “religious” is much more common in the USA [
32,
33]. There are many more widely recognized spiritual practices, religions, and denominations of Christian churches in the USA than in Germany allowing for more individualized selections of a religious community. The USA is an example of the religious market model in terms of the theory of pluralization in contrast to the theory of secularization, which is predominant in Germany [
34]. The Protestant community and the Catholic community are the two major churches in Germany. Most German members of a religious community were raised in religious homes and they rarely change their religion. The German churches are more secularized (e.g. with the implementation of church tax) and therefore the construct cannot be transferred to the German context [
33,
35]. Also, according to surveys, even 27 years after German reunification half of the people in former East Germany describe themselves as not being religious or spiritual in contrast to people from former West Germany [
36,
37]. But we cannot make any statement according to the socialization in our sample, because we have only asked where the participants live at the time of the survey and not where they grew up or were socialized.
There have been various studies from Anglo-American regions that have measured spirituality within the context of health-related quality of life [
38‐
40]. And some measurements have included spirituality as a psychological or social domain such as the MHIQ or the WHQOL-100 [
41,
42].
Although a link has been found between quality of life and spirituality, little is known about the causal direction of this association. Previous research indicates positive effects of spirituality on quality of life especially for older cancer patients and patients in palliative treatment [
43‐
46]. So far though, there has been a paucity of research investigating the impact of spirituality on quality of life in adolescent and young adult cancer patients. We therefore recommend assessing the “spiritual quality of life” based on additional modules of quality of life measures (e.g. FACIT-Sp [
47] or WHOQOL-SRPB [
48]). But there is ongoing controversy in research whether to integrate or exclude spirituality and religion in the concept of health-related quality of life [
49].
Additionally, further research should investigate the application of the German scale in clinical practice with a larger sample to enable comparisons between several tumour entities. Because, as already mentioned by Park et al. [
22], some issues like fertility may not be relevant to all AYAs (e.g. the adolescents and younger adults) longitudinal studies with a broader age range should be conducted to compare quality of life issues between age subgroups within the AYA population and to observe developments according to treatment related sequelae.
Conclusions
In summary, the presented data support a valid and reliable instrument for measuring health-related quality of life that provides valuable information for physicians in the management with young cancer patients.
Good psychometric properties confirmed the use of the German satisfaction scale of the LAYA-SRQL in psychooncological research of the AYA population. Future studies should consider reducing the scale of this assessment tool for more economical use in clinical follow-up care.