Background
Cancer is one of the leading causes of morbidity and mortality worldwide [
1,
2]. An estimated 3.2 million new cancer cases were diagnosed in Europe in 2008 [
1]. The most frequent forms of cancer were colorectal cancers (13.6% of all cancer cases), breast cancer (13.1%), lung cancer (12.2%) and prostate cancer (11.9%). In Germany, recent epidemiological estimates indicate a projected annual incidence rate for 2010 of about 450,000 cancer cases [
3]. Cancer incidence statistics show an enhanced 5-year survival rate up to 62% for women and 57% for men, including all cancer stages. The average age of onset of cancer is 69 years for both genders. For the population of 82 million people in Germany, these developments lead to a prevalence of 1.4 million cancer patients within the range of five years post diagnosis and 2.1 million cancer patients in whom the diagnosis is back up to 10 years [
3].
Given both the high cancer incidence and continuous advances in cancer detection, multimodal treatments and targeted therapies, the proportion of cancer survivors continues to grow in industrialized countries. Cancer survivorship covers a variety of medical conditions and periods that are divided into acute survival, middle and long-term survival including disease-free survival as well as cancer recurrence and chronic disease [
4]. Thus, short, middle and long-term survivorship has significant implications for both clinical and psychosocial research as well as for health care services research [
5‐
7].
Comprehensive patient-centered care in oncology has been emphasized in international guidelines and standards [
8], implying cancer prevention and early detection as well as high quality evidence-based medical treatment, rehabilitation and palliative care. Improving the quality of care requires recognition and addressing patients’ distress, mental disorders and supportive care needs during treatment and after care. Thus, psychosocial and psycho-oncological support services considerably contribute to improving the quality of life of patients as a central outcome criterion of oncological care [
9].
Emotional distress is common after a cancer diagnosis [
10], and is often a result of a variety of problems that can affect every aspect of life according to different stages of the disease. Typical issues relate to physical symptoms and problems such as pain, functional impairments and states of chronic fatigue, family burden such as the uncertainty about individual roles and responsibilities, existential concerns such as isolation or meaning in one's life as well as social, financial and occupational problems [
11].
Many cancer patients suffer from a high symptom burden, which can remain for months and years after the initial cancer therapy or can occur again in the face of long-term therapy or complications in the disease trajectory. High symptom burden is associated with a significant increase in feelings of helplessness and hopelessness and may adversely impact a patient’s quality of life [
12‐
14]. The spectrum of emotional reactions and psychosocial consequences ranges along a continuum including anxiety, fear, sadness and depression, helplessness and hopelessness as well as adjustment disorders, anxiety disorders, posttraumatic stress disorder, depression, family conflicts or existential crises [
11,
15‐
17].
Empirical studies investigating the prevalence of mental disorders and the frequency of psychosocial burden in cancer patients have gained increasing importance during recent years [
18]. This research is of particular significance for the development and implementation of psychosocial support offers within the health care system. Recent meta-analytical evidence indicates that the overall prevalence of mental disorders among cancer patients ranges from 9.8% to 38.2% in various cancer settings [
19,
20]. In an international review conducted by Mitchell et al. [
19] including 94 interview-based studies, the prevalence of depression by DSM or ICD criteria in oncological and hematological settings (70 studies) was 16.3% (95% CI 13.4–19.5); the prevalence of dysthymia was 2.7% (95% CI 1.7–4.0); the prevalence of adjustment disorder was 19.4% (95% CI 114.5–24.8); and the prevalence of anxiety disorders was 10.3% (95% CI 5.1–17.0). However, combination diagnoses were prevalent among up to 38.2% (95% CI 28.4–48.6) of patients. The prevalence of depression by DSM or ICD criteria in palliative-care settings (24 studies) was 16.5% (95% CI 13.1–20.3); the prevalence of adjustment disorder was 15.4% (95% CI 10.1–21.6); the prevalence of anxiety disorders was 9.8% (95% CI 6.8–13.2); and combination diagnoses were prevalent among up 29.0% (95% CI 10.1–52.9) of patients. Accordingly, Singer et al. [
20] observed prevalence rates up to 32% (95% CI 27–37) among cancer patients in acute hospitals.
However, few trials have examined the prevalence of mental disorders in cancer patients taking into account the wide spectrum of mental disorders including substance abuse or somatoform disorders, different health care settings as well as different tumor entities and disease stages for both genders. Fewer studies have examined the 4-week-, 12-month-, and lifetime prevalence rates of comorbid mental disorders in cancer patients [
21] and the association between comorbid mental disorders and psychological distress.
The presence of a mental disorder or psychological symptom burden is not necessarily associated with subjective needs of patients for professional psychosocial support and the utilization of relevant offers [
22]. Although a variety of psychological interventions have been shown to be effective in the reduction of psychosocial symptom distress and the improvement of quality of life [
23‐
25], however, improving distress screening and the access of cancer patients to adequate psychosocial care remains a critical concern [
26]. Thus epidemiological data about mental comorbidity, psychological symptom burden and supportive care needs are essential for the evidence based implementation of psychosocial support offers within oncological health care.
Objectives
Although there has been extensive research looking at emotional distress among various cancer entities, there is limited evidence regarding prevalence rates of comorbid mental disorders in cancer patients across different tumor entities and care settings from an epidemiological point of view. Main research aim of this epidemiological cross-sectional multi-center study is to detect the 4-week-, 12-month-, and lifetime prevalence rates of comorbid mental disorders according to the ICD-10/DSM-IV (organic, including symptomatic, mental disorders, mental and behavioral disorders due to psychoactive substance use, mood disorders, neurotic, stress-related and somatoform disorders, and behavioral syndromes associated with physiological disturbances and physical factors); and to further assess psychological distress and psychosocial supportive care needs in cancer patients across all major tumor entities within the in- and outpatient oncological health care and rehabilitation settings in Germany.
Secondary aims are to examine the impact of demographic, functional, cancer- and treatment-related risk factors on the occurrence of mental comorbidity, psychosocial distress, specific supportive care needs and use of psychosocial support offers. Associations between mental comorbidity, psychosocial distress, supportive care needs, quality of life and medial decision-making will be also examined.
Discussion
Primary purpose of this epidemiological multi-center study was to detect the 4-weeks-, 12-months-, and lifetime-prevalence rates of comorbid mental disorders according to the ICD/DSM in cancer patients. We aim to enroll a representative sample of patients in terms of tumor entities and cancer care facilities. On the basis of epidemiological data on the prevalence of mental disorders and distress, the needs and demands for the type and extent of psychosocial support offers can be estimated.
This study was methodologically strong relative to many studies previously conducted. Our study used a cancer-incidence-based recruitment strategy for both genders and a multi-methodological approach including a computer-based structured clinical interview for the assessment of mental disorders including adjustment disorder as well as validated questionnaires for the assessment of subjective emotional distress and supportive care needs. Our targeted sample size is larger than those of earlier studies in cancer patients which allow a variety of subgroup analyses stratified by important risk factors such as cancer progress and limited physical functioning.
We use a statistical model that takes different sources of variability into regard in order to allow reliable projections for cancer comorbidities that have to be faced in Germany over the next years.
In summary, our study will provide a large data set offering detailed and valid information about the specific mental comorbidities, problems and emotional distress among cancer survivors with various tumor entities and disease states. The data further will provide information about specific demographic, functional, cancer- and treatment-related risk factors for mental comorbidity and psychosocial distress, specific supportive care needs and use of psychosocial support offers.
Thus, epidemiological data provide an important basis for the implementation of both information and psychosocial support offers in different health care settings. The identification of predictors for psychosocial support needs in cancer patients allow an early and specific assignment and referral of those patients to adequate psychosocial support offers. Medical health care will be improved by the prevention of chronification of mental disorders and the enhancement of compliance, treatment satisfaction, quality of life and communication between the cancer patient and the health care team.
Competing interests
The authors declare that they have no competing interests.
Authors’ contribution
All authors collectively drafted the study protocol and approved the final manuscript. AM is its guarantor.