Physical and psychological correlates of high somatic symptom severity in Chinese breast cancer patients

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1 Received: 22 February 2016 Revised: 2 June 2016 Accepted: 24 June 2016 DOI: /pon.4203 PAPER Physical and psychological correlates of high somatic symptom severity in Chinese breast cancer patients Rainer Leonhart 1 Lili Tang 2 Ying Pang 2 Jinjiang Li 2 Lili Song 2 Irmela Fischer 3 Maike Koch 3 Alexander Wuensch 4 Kurt Fritzsche 3 Rainer Schaefert 5 1 Institute of Psychology, University of Freiburg, Freiburg, Germany 2 Psycho Oncology Department, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Psycho Oncology, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, China 3 Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Freiburg, Freiburg, Germany 4 Division of Psychosocial Oncology, Department of Psychosomatic Medicine and Psychotherapy, TUM MEC, Klinikum rechts der Isar, Technical University Munich, Munich, Germany 5 Department of General Internal Medicine and Psychosomatics, University of Heidelberg Medical Centre, Heidelberg, Germany Correspondence Kurt Fritzsche, MD, Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Freiburg, Hauptstraße 8, D Freiburg, Germany. kurt.fritzsche@uniklinik freiburg.de Abstract Objective: We researched associations between somatic symptom severity (SSS), and physical and psychological factors in Chinese breast cancer patients. Methods: This multicenter cross sectional study enrolled 255 Chinese breast cancer patients of different stages and treatment phases. They answered standard instruments assessing SSS (Patient Health Questionnaire [PHQ] 15), depression (PHQ 9), anxiety (General Anxiety Disorder [GAD] 7), health anxiety (Whiteley 7[WI 7]), illness perception (Brief Illness Perception Questionnaire [IPQ]), illness attribution (Illness Perception Questionnaire Revised [IPQ R]), and sense of coherence (Sense of Coherence [SOC] 9). Logistic regression was applied to identify the strongest correlates with SSS. Results: Our sample of high (PHQ 15 10) and low SSS differed significantly in the following physical and psychological variables: symptom duration (r = 0.339, P <.001), symptom related disability (Karnofsky Index) (r = 0.182, P <.001), depression (r = 0.556, P <.001), anxiety (r = 0.433, P <.001), health anxiety (r = 0.400, P <.001), illness perception (r = 0.349, P <.001), psychological illness attributions (r = 0.217, P <.01), and sense of coherence (r = 0.254, P <.001). In an adjusted stepwise multiple binary logistic regression analysis, higher health anxiety (WI 7, B = 0.388, P =.002), higher depression (PHQ 9, B=0.158, P <.001),youngerage(B = 0.042, P =.048), higher impairment in daily life (B =1.098,P =.010), and longer symptom duration (Wald = , P =.001) showed a significant association with high SSS; the model explained 55.1% of the variance. Conclusions: High somatic symptom burden in breast cancer is associated with physical and psychosocial features. The results are a basis for further research to evaluate the new Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, SSD concept in cancer patients and to better operationalize psychobehavioral factors in this patient group. KEYWORDS breast cancer, health anxiety, oncology, somatic symptom disorder, somatic symptom severity 1 BACKGROUND High somatic symptom severity (SSS) magnifies disability resulting from cancer and reduces overall well being and quality of life. 1 There is a common belief among biomedically oriented oncologists that when somatic symptoms occur in a person with a diagnosed cancer, these symptoms are due to the underlying cancer disease or its treatment. 2 4 However, cancer related somatic symptoms are strongly influenced by physical, as well as cognitive and emotional factors, hence pointing to an association between somatic symptoms, illness perception, depression, anxiety, and cancer itself. 5,6 Leventhal's self regulatory model has been widely used to describe how individuals respond to somatic symptoms regardless of etiology. 7 The model proposes that in facing somatic symptoms, individuals develop a certain cognitive and emotional illness perception that motivates corresponding illness behavior to cope with these symptoms. Some Western studies have found strong evidence supporting the use of some psychological variables to identify people with high SSS. 8,9 Recently, Diagnostic and Statistical Manual of Mental 656 Copyright 2016 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/pon Psycho Oncology. 2017;26:

2 LEONHART ET AL. 657 Disorders, Fifth Edition, defined Somatic Symptom Disorder (SSD) as a new category, de emphasized the central role of medically unexplained symptoms and defined the disorder on the basis of health anxiety, disproportionate and persistent thoughts about the medical seriousness of one's symptoms, and excessive time and energy devoted to these symptoms (B criteria). 9,10 Consequently, the specifier of severity is no longer based on the number of somatic symptoms but on the amount of these psychological features that are specified under the B criteria. Health related anxiety, excessive somatic concerns, and preoccupation have also been described in cancer patients: a preexisting tendency to worry and negative affectivity may, for example, lead to increased worries about somatic symptoms and increased sensitization to pain, together with increased recall of negative health related information. 11 This may be accompanied by inaccurate bodily interception, so that the perception of symptoms in combination with illness worries may lead to the interpretation of harmless bodily sensations as symptoms of cancer progression Culture and cancer perception Traditionally, China was believed to be among low incidence areas of breast cancer. 12 However, in the past 2 decades, China experienced an ever increasing incidence of breast cancer, twice as fast as global rates. 13 According to the latest Chinese Cancer Registry Annual Report 14 from 2014, breast cancer has become the most common cancer among Chinese women. The reason for this is not clear, but consequently breast cancer came more in the focus of Chinese oncology. Similar to patients from Western countries, 15 breast cancer survivors in China experienced a high level of depressive and anxiety symptoms. Higher levels of depression and anxiety were positively associated with a higher level of passive coping style, and negatively with perceived social support, objective social support, and an active coping style. 16,17 However, the cultural background shapes the interpretation of somatic symptoms in cancer patients and thereby influences an individual's illness perception and attribution. 18,19 Up to now, there is a lack of studies on SSS experienced by cancer patients. 1,6 If it is addressed, it is usually interpreted as a consequence of depression 3 or of the underlying physical illness, 4 but it has rarely been studied as a somatizing reaction after adjustment for these potential confounders. To date, no study has focused on the relationship between SSS and psychological variables in Chinese cancer patients. 1.2 Study objectives The aim of this study was to evaluate psychological features among Chinese breast cancer patients with high SSS. Our specific research aims were as follows: 1. to analyze how Chinese breast cancer patients with high SSS (Patient Health Questionnaire [PHQ] 15 10, SOM+) differ from patients with low SSS (PHQ 15 < 10, SOM ) in terms of sociodemographic and clinical data, emotional distress, healthrelated anxiety, illness perception, illness attribution, and sense of coherence; and 2. to evaluate which of these psychological and cognitive variables may serve as the strongest correlates of high SSS, after adjustment for potential confounders. 2 METHODS 2.1 Study design and setting This study is part of the Sino German research network entitled Patients with multiple somatic symptoms in China. We performed a multicenter, cross sectional study in 3 Beijing hospitals (Beijing Cancer Hospital: Department of Psycho oncology and Department of Traditional Chinese Medicine), People's Liberation Army (PLA) Military Hospital (Departments of Medical Oncology and Gynaecology), and Beijing Tiantan Hospital (Breast Surgery Department). The study was approved by the ethic committees of the 2 principal investigators (L.T. and K.F.), university affiliations, the Beijing Cancer Hospital, and the University Medical Centre, Freiburg, Germany. 2.2 Subjects The study was performed under routine clinical conditions on randomly assigned screening days between July 1, 2012 and June 30, Patients who entered a participating department of the above named hospitals on one of the screening days were informed about the study by research assistants and were asked to participate. Written informed consent was obtained from all participants. Research assistants were well trained clinical research nurses or medical master students, which were under the supervision of LT. Inclusion criteria were age older than 18 years, a diagnosis of breast cancer, and adequate reading and writing skills. Exclusion criteria comprised severe physical and cognitive impairment, psychosis, and acute suicidal tendencies. 2.3 Sociodemographic data and physical characteristics The medical records were used to determine duration of cancer (time in days since diagnosis), Karnofsky Performance Index Status (ranges from 0 [ death ] to 100 [ perfect health ]), cancer stage (0 to 4 or unknown), tumor size (Tis, T1 T4), lymph nodes status (NX, N0 N3), metastases (MX, M0, and M1) (for more information, see treatment (surgery, hormonal therapy, chemotherapy, radiotherapy), and other severe diseases. Information on symptom duration, impairment in daily life, and doctor visits was collected. 2.4 Assessment instruments We used the following questionaires: Somatic Symptom Severity Scale of the Patient Health Questionnaire (PHQ 15) ; depression scale of the Patient Health Questionnaire (PHQ 9) 25,26 ; anxiety scale (GAD 7) 27,28 ; health related anxiety (WI 7) 29,30 ; the brief illness perception questionnaire (Brief IPQ) 31,32 ; illness attribution (IPQ R) 31,33 ;

3 658 LEONHART ET AL. and sense of coherence (SOC 9). 34,35 Details on the questionnaires can be found in Supporting Information. psychological variables. For the other data, the percentage of missing data was less than 3% except the Karnofsky Index (7.5% missing). 2.5 Sample size calculation Through G Power, we calculated the sample size that we needed for a t test (2 independent means), 2 tailed for an effect size d = 0.5 (α error probability = 0.05, power (1 β error probability) = 0.95) for a critical t = , df = 208, resulting in a sample size of n = 105 for each group. The estimated effect size is based on our previous study about SSS in general hospital outpatients in China Statistical analyses Statistical analyses were performed with IBM SPSS Statistics 23.0 and MPlus. Two groups (high SSS, PHQ 15 10, SOM+; and low SSS, PHQ 15 < 10, SOM ) were defined. Categorical variables were evaluated using the χ 2 test. Continuous variables were evaluated using the t test. Correlation coefficients were calculated to assess the relationships between SSS, clinical characteristics, and psychological variables. Preliminary univariate analyses were conducted to compare the sociodemographic, clinical, and psychological characteristics between SOM+ and SOM breast cancer patients. Blockwise stepwise binary logistic regressions were used to identify the strongest correlates of high SSS. In the first block, the offered predictors were Whiteley 7, B IPQ, all illness attribution scales, frequency of causes of illness, and SOC 9. In the second block, the offered predictors were PHQ 9, GAD 7, Karnofsky, age, days since diagnosis as interval scaled predictors and doctor visits, duration of symptoms, health insurance, family status, life situation, income, employment, education, and cancer stage as categorical predictors. The Wald test was used as additional method to estimate the significance of coefficients in the multiple binary logistic regression analysis. It is a parametric way of testing the significance of particular explanatory variables in a statistical model, analogous to the t value in linear regression. Cox and Snell R 2 and Nagelkerke R 2 quantify the proportion of variation explained by the regression model; higher values of R 2 indicate a better model fit. Nagelkerke R 2 is a modification of the Cox and Snell R 2 to ensure that it can vary from 0 to 1 because the Cox and Snell R 2 has a value less than 1 even for a perfect model. Because the dependent variable is binary, these are only estimations. Statistical analyses were conducted using an α level of 1% to avoid alpha inflation resulting from multiple tests. For the stepwise regression, we used an α level of 5%. 3 RESULTS 3.1 Study sample A total of 269 breast cancer patients fulfilled the inclusion criteria, and 255 patients (94.8%) provided informed consent. The documentation of the cancer stage in the charts was incomplete (22% unknown). But the patients with missing data and the ones with complete data did not differ regarding SSS and sociodemographic, clinical, or 3.2 Sociodemographic characteristics The sociodemographic characteristics of our 255 patients are shown in Table 1. Overall, SOM+ patients and SOM patients did not significantly differ in their sociodemographic characteristics. SOM+ patients showed a trend to be younger and living with a partner, children, or parents. 3.3 Oncological characteristics and somatic symptoms The sample was representative of typical diagnosis and treatment diversity among women with breast cancer in China 2 4 ; 57% of the patients were diagnosed with stage 1 and 2 cancer. The vast majority of the sample had some type of surgical procedure (n = 229), as well as chemotherapy or hormone therapy (n = 228); n = 103 patients received radiotherapy. Breast cancer patients with high SSS (SOM+ patients) did not significantly differ from SOM patients regarding the following oncological characteristics: time in days since diagnosis, cancer stage, cancer size, involved lymph nodes, metastases, treatment, and other severe diseases. As compared with SOM patients, SOM+ breast cancer patients had a significantly longer symptom duration and a lower Karnofsky score; they were significantly more impaired in their everyday live and visited doctors more often during the last 12 months. The most frequent somatic symptoms in descending order were: feeling tired or having low energy (fatigue), trouble sleeping, pain in arms, legs or joints, nausea, gas, or indigestion, constipation, loose bowel, or diarrhea, feeling your heart pound or race, back pain, stomach pain, and dizziness (see Figure 1). 3.4 Psychological features Breast cancer patients with high SSS (SOM+ patients) significantly differed from SOM patients regarding nearly all analyzed psychological features: As compared with SOM patients, SOM+ breast cancer patients displayed higher depression (PHQ 9), anxiety (GAD 7), and health related anxiety (WI 7); more threatening and negative illness perceptions (B IPQ); more illness attribution to psychological causes (IPQ R); and a lower SOC (SOC 9) (Table 2). 3.5 Relationship between low SSS and other variables An adjusted stepwise multiple binary logistic regression analysis with all sociodemographic, physical, and psychological variables showed a significant relationship between high SSS and higher health anxiety (WI 7, B = 0.388, P =.002), higher depression (PHQ 9, B = 0.158, P <.001), younger age (B = 0.042, P =.048), higher impairment in daily life (B = 1.098, P =.010), and longer symptom duration (Wald = , P =.001). The model revealed a Cox and Snell R 2 of and a Nagelkerke R 2 of 0.511; 79.5% of the subjects were correctly assigned to the groups by this model (see Table 3).

4 LEONHART ET AL. 659 TABLE 1 Sociodemographic characteristics Total SOM (PHQ 15 < 10) SOM+ (PHQ 15 10) χ 2 /t Variable N = 255 N = 144 N = 111 Value df P Age Mean years (SD) 49.8 (10.1) 51.1 (9.9) 48.3 (10.1) Health insurance Yes 215 (86.7%) 122 (87.1%) 93 (86.1%) No 33 (13.3%) 18 (12.9%) 15 (13.9%) Residence Urban 215 (86.0%) 122 (86.5%) 93 (85.3%) Rural 35 (14.0%) 19 (13.5%) 16 (14.7%) Marital status Single 8 (3.1%) 3 (2.1%) 5 (4.5%) Married 230 (90.6%) 131 (91.6%) 99 (89.2%) Married but separated 4 (1.6%) 1 (0.7%) 3 (2.7%) Divorced 7 (2.8%) 5 (3.5%) 2 (1.8%) Widowed 5 (2.0%) 3 (2.1%) 2 (1.8%) Life situation Alone 14 (5.5%) 7 (4.9%) 7 (6.3%) With partner 72 (28.3%) 50 (35.0%) 22 (19.8%) Alone with children 15 (5.9%) 11 (7.7%) 4 (3.6%) With partner and children 135 (53.1%) 68 (47.6%) 67 (60.4%) With parents 16 (6.3%) 6 (4.2%) 10 (9.0%) Other 2 (0.8%) 1 (0.7%) 1 (0.9%) Family income (monthly) Low (under 4000 RMB a ) 132 (53.0%) 73 (52.1%) 59 (54.1%) Middle ( RMB) 81 (32.5%) 50 (35.7%) 31 (28.4%) High (above 8000 RMB) 36 (14.5%) 17 (12.1%) 19 (17.4%) Employment Employed 88 (35.5%) 49 (35.0%) 39 (36.1%) Unemployed 31 (12.5%) 15 (10.7%) 16 (14.8%) Retired 114 (46.0%) 68 (48.6%) 46 (42.6%) Homemaker 13 (5.2%) 6 (4.3%) 7 (6.5%) Student 1 (0.4%) 1 (0.7%) 0 (0.0%) Other 1 (0.4%) 1 (0.7%) 0 (0.0%) Education Elementary school 14 (5.6%) 7 (5.0%) 7 (6.4%) Middle school 53 (21.3%) 31 (22.3%) 22 (20.0%) High school 89 (35.7%) 53 (38.1%) 36 (32.7%) University degree 93 (37.3%) 48 (34.5%) 45 (40.9%) Abbreviation: PHQ, Patient Health Questionnaire. All % are column percentages. a RMB: The renminbi is the currency of the People's Republic of China; 1000 RMB is equivalent to approximately 130 Euro. 4 DISCUSSION 4.1 Summary of main results We performed a cross sectional study to investigate associations between SSS and physical, as well as psychological variables in Chinese breast cancer patients. In answering our first research question, Chinese breast cancer patients with high SSS in comparison with patients with low SSS had higher emotional distress, increased health related anxiety, more negative and threatening illness perception, more psychological illness attributions, and a lower SOC. They had a significantly longer symptom duration, a higher number of doctor visits, more impairment in daily life, and a lower Karnofsky Performance Index. No differences were found regarding sociodemographic characteristics and clinical data such as age, living alone, and cancer stage. In answering our second research question, an adjusted stepwise multiple binary logistic regression analysis found that higher health anxiety, higher depression, younger age, higher impairment in daily life, and longer symptom duration were the strongest correlates of high SSS.

5 660 LEONHART ET AL. FIGURE 1 Proportion of the reported Patient Health Questionnaire (PHQ) 15 symptoms in the total sample (n = 255) 4.2 High SSS in cancer patients In cancer patients with high SSS, the most frequent somatic symptoms were fatigue, trouble sleeping, pain in different parts of the body, and gastrointestinal complaints. The most common somatic symptoms in cancer patients in Western countries are also fatigue, pain, weakness, reduced energy, loss of appetite, dry mouth, constipation, insomnia, dyspnea, tremors, and nausea. 13,14 Fatigue, sleep concerns, memory impairment, and musculoskeletal pain were the most common somatic symptoms reported in patients with cancer experiencing pain or depression in the United States. 1 Higher levels of pain intensity in cancer patients have been found to be associated with mood disturbances like depression, frustration, anger, exhaustion, maladaptive behavioral coping responses, beliefs that pain is related to cancer progression, greater life stress, and feelings of helplessness and hopelessness. 37 When compared with chronic pain patients with similar pain scores, patients with cancer have significantly higher levels of cognitive and behavioral fear responses to pain, and they think and worry more about it High SSS and psychological variables In our own 2 previous studies about psychobehavioral characteristics in a mixed sample of Chinese General Hospital outpatients, we found strong correlations between high SSS and cognitive, affective, and behavioral features such as depression, anxiety, catastrophizing, illness vulnerability, and dysfunctional illness behavior. 22,36 We now found a similar pattern in our more homogenous group of physically ill cancer patients. This once more questions the distinction between medically unexplained and medically explained symptoms Culture influences Historically, there has been a popular belief that Asians manifest a lower prevalence of mood and anxiety disorders than their Western counterparts because they are more prone to experiencing and manifesting distress via somatic pathways. 18,19 The results of our study showed that patients report somatic symptoms and emotional distress together on a high level. 4.5 Strengths and limitations This is the first study that assessed the association between physical and psychological variables, and SSS in Chinese cancer patients. The study population was representative of Chinese breast cancer patients regarding sociodemographic data, cancer stage, and treatment. The study also had some limitations: (1) because of the cross sectional nature of our study, causality could not be inferred. Accordingly, the degree to which the patients' illness related thoughts and emotions are the consequence of breast cancer and its treatment cannot be answered. (2) First or secondline treatment as well as the chance of survival might also be a major source for experienced distress and might influence our results. We have controlled for treatment, but not for first treatment or different pretreatments. We did not assess the chance of survival that is difficult to determine in a specific patient and could primarily be addressed in long term studies. (3) The questionnaire to measure health anxiety (WI 7) originally was developed for patients with

6 LEONHART ET AL. 661 TABLE 2 Relationship between clinical variables and somatic symptom severity (PHQ 15) Total SOM (PHQ 15 < 10) SOM+ (PHQ 15 10) Correlation With PHQ 15 N = 255 N = 144 N = 111 χ 2 Spearman Categorical Variables, χ 2 Test n (%) n (%) n (%) Value df Correlation Cancer stage Stage 0 2 (0.8%) 2 (1.4%) 0 (0.0%) Stage 1 38 (14.9%) 28 (19.4%) 10 (9.0%) Stage (42.0%) 63 (43.8%) 44 (39.6%) Stage 3 28 (11.0%) 10 (6.9%) 18 (16.2%) Stage 4 24 (9.4%) 14 (9.7%) 10 (9.0%) Stage unknown 56 (22.0%) 27 (18.8%) 29 (26.1%) Symptom duration <4 weeks 81 (32.9%) 61 (44.5%) 20 (18.3%) 22.56*** 4.339** 4 weeks to 6 months 55 (22.4%) 28 (20.4%) 27 (24.8%) 6 months to 1 year 45 (18.3%) 21 (15.3%) 24 (22.0%) 1 2 years 26 (10.6%) 14 (10.2%) 12 (11.0%) >2 years 39 (15.9%) 13 (9.5%) 26 (23.9%) Do your complaints affect your daily life? Yes 142 (56.8%) 58 (41.4%) 84 (76.4%) 30.64*** 1.389** No 108 (43.2%) 82 (58.6%) 26 (23.6%) Number of doctor visits during the previous 12 months 0 52 (20.6%) 39 (27.5%) 13 (11.8%) ** (23.4%) 34 (23.9%) 25 (22.7%) (33.3%) 45 (31.7%) 39 (35.5%) (12.3%) 13 (9.2%) 18 (16.4%) >20 26 (10.3%) 11 (7.7%) 15 (13.6%) Continuous Variables, t Test M (SD) M (SD) t Value df Pearson Correlation Time since diagnosis in days (58.20) 5.78 (2.934) 6.63 (2.92) Karnofsky b (range, 0 100) (7.55) (5.64) (9.22) 3.553** ** Depression (PHQ 9) a (range, 0 27) 7.39 (5.80) 4.94 (4.62) (5.66) 8.471*** *** Anxiety (GAD 7) a (range, 0 21) 4.87 (4.77) 3.46 (3.96) 6.68 (5.12) 5.462*** *** Health related anxiety a (WI 7) (range, 0 7) 4.29 (2.07) 3.67 (2.13) 5.09 (1.69) 5.933*** *** Brief IPQ a (total score) (range, 0 80) (12.46) (12.93) (10.57) 4.845*** *** Illness attribution Personal risk factors 8.56 (3.06) 9.02 (3.31) 8.21 (2.82) Psychological causes (3.85) (3.87) (3.63) 3.533*** ** External risk factors (2.90) (2.99) (2.66) 3.072** Burden (2.14) (2.11) (2.13) Medical causes 4.73 (1.75) 4.75 (1.76) 4.71 (1.75) Number of causes 6.15 (2.96) 5.78 (2.94) 6.63 (2.92) Sense of coherence b (SOC 9) (range, 9 63) (9.73) (9.49) (9.65) 3.166** *** Abbreviation: M, mean; PHQ, Patient Health Questionnaire; SD, standard deviation. All % are column percentages. a A higher score represents a poorer condition. b A higher score represents a better condition. ***P <.001. **P <.01. hypochondriasis without severe medical conditions. (4) The factor structure of the IPQ R has to be interpreted cautiously. (5) It should be noted that the research approach used a Western biopsychosocial model of illness. Therefore, possible culture specific characteristics may not have been identified, even if there appear to be cross cultural similarities in psychobehavioral characteristics of SSS.

7 662 LEONHART ET AL. TABLE 3 Prediction of the belonging to a high somatic symptom group (PHQ 15 10) using a stepwise multiple binary logistic regression analysis (hierarchical design) Variables B SE B Wald P Exp (B) 95% CI 95% CI+ Health anxiety (WI 7) Negative illness perception (B IPQ) Depression (PHQ 9) < Age complaints affect daily life (yes) Symptom duration <4 weeks < weeks to 6 months months to 1 year years Constant Cox and Snell R 2 = 0.379; Nagelkerke R 2 = % CI /+, 95% confidence interval of Exp (B); B, regression coefficient; Exp (B), exponential coefficient, odds ratio for dummy variables; PHQ, Patient Health Questionnaire; SE B, standard error of the regression coefficient; Wald, ratio of B 2 to SE B 2. Reference category for symptom duration was more than 2 years (category 5). Cox and Snell R 2 and Nagelkerke R 2 quantify the proportion of variation explained by the regression model. 5 CONCLUSIONS The major clinical implication of this study was to broaden the view on psychological variables, which should be measured and addressed routinely in cancer patients. A simple measure of cognitive, affective, and behavioral aspects associated with the bothersome somatic symptoms may be important. 40 Our study is a good basis for further research to evaluate the new Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, SSD concept in cancer patients and to better operationalize psychobehavioral factors in this patient group. ACKNOWLEDGMENTS We are very grateful to the Chinese team that worked on this study. Data analyses and writing of the manuscript were supported by grant GZ 690 awarded by the Centre for Sino German Research Promotion in Beijing to Kurt Fritzsche and Zhao Xudong. Furthermore, we extend our sincere thanks to Shikai Wu, Fang Li, and Pilin Wang for the support during the data collection. We thank Anne Kristin Toussaint and Ricarda Nater Mewes for their suggestions to improve the manuscript. The cooperation of the participating patients is also gratefully acknowledged. We thank the American Journal Experts for proofreading the manuscript. REFERENCES 1. Kroenke K, Zhong X, Theobald D, Wu J, Tu W, Carpenter JS. Somatic symptoms in patients with cancer experiencing pain or depression: prevalence, disability, and health care use. Arch Intern Med. 2010;170: Chaturvedi SK, Maguire GP. Persistent somatization in cancer: a controlled follow up study. J Psychosom Res. 1998;45: Chaturvedi SK, Maguire GP, Somashekar BS. Somatization in cancer. Int Rev Psychiatry. 2006;18: Andritsch E, Dietmaier G, Hofmann G, Zloklikovits S, Samonigg H. Global quality of life and its potential predictors in breast cancer patients: An exploratory study. Support Care Cancer. 2007;15: Chaturvedi SK, Hopwood P, Maguire P. Non organic somatic symptoms in cancer. Eur J Cancer. 1993;29: Novy D, Berry MP, Palmer JL, Mensing C, Willey J, Bruera E. Somatic symptoms in patients with chronic non cancer related and cancer related pain. J Pain Symptom Manage. 2005;29: Leventhal H, Brissette I, Leventhal EA. The common sense model of self regulation of health and illness. In: Cameron LD, Leventhal H, eds. The Self regulation of Health and Illness Behaviour. London: Routledge;2003: Rief W, Mewes R, Martin A, Glaesmer H, Braehler E. Are psychological features useful in classifying patients with somatic symptoms? Psychosom Med. 2010;72: Voigt K, Wollburg E, Weinmann N, et al. Predictive validity and clinical utility of DSM 5 Somatic Symptom Disorder comparison with DSM IV somatoform disorders and additional criteria for consideration. J Psychosom Res. 2012;73: American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. (DSM 5)Arlington, VA: American Psychiatric Publishing; 2013: Zaza C, Baine N. Cancer pain and psychosocial factors: a critical review of the literature. J Pain Symptom Manage. 2002;24: Ferlay J, Soerjomataram I, Dikshit R, et al. Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN Int J Cancer. 2015;136:E359 E Fan L, Zheng Y, Yu KD, et al. Breast cancer in a transitional society over 18 years: trends and present status in Shanghai, China. Breast Cancer Res Treat. 2009;117: Chinese Cancer Registry Annual Report, 113, National Office for Cancer Prevention and Control, National Center for Cancer Registry, Disease Prevnetion and Control Bureau, MOH (ed). Military Medical Sciences Press: Beijing, Mehnert A, Brähler E, Faller H, et al. Four week prevalence of mental disorders in patients with cancer across major tumor entities. J Clin Oncol. 2014;32: Lam WW, Bonanno GA, Mancini AD, et al. Trajectories of psychological distress among Chinese women diagnosed with breast cancer. Psycho Oncology. 2010;19: Wang F, Liu J, Liu L, et al. The status and correlates of depression and anxiety among breast cancer survivors in Eastern China: a populationbased, cross sectional case control study. BMC Public Health. 2014;14:326

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