Vol.
-
No.
- -
2014
Journal of Pain and Symptom Management 1
Original Article
Chronic Pain in Breast Cancer Survivors: Comparison of Psychosocial, Surgical, and Medical Characteristics Between Survivors With and Without Pain Inger Schou Bredal, PhD, Nina A. Smeby, PhD, Stig Ottesen, MD, Torhild Warncke, PhD, and Ellen Schlichting, PhD Oslo University Hospital (I.S.B., S.O., T.W., E.S.) and University of Oslo (I.S.B., N.A.S., S.O.), Oslo, Norway
Abstract Context. According to literature, 25%e60% of women treated for breast cancer, regardless of the stage, experience pain. Many risk factors have been suggested, with many possible confounding factors. Objectives. The aim was to investigate psychosocial, surgical, and medical factors associated with chronic pain by comparing breast cancer survivors with chronic pain with survivors without chronic pain. In addition, we investigated the prevalence, intensity, and body location of chronic pain after breast cancer treatment nationwide. Methods. A nationwide postal survey of 1332 women who received surgery and adjuvant therapy for breast cancer in Norway two to six years before the onset of this study. Results. A total of 832 women (63%) returned the questionnaires, and 41% reported pain, of which 51% had mild, 41% moderate, and 8% severe pain. Among the women who experienced pain, 33.8% reported symptoms and signs of neuropathic pain. Young age (odds ratio [OR], 0.95; 95% CI, 0.93e0.98; P < 0.0001), axillary lymph node dissection with subsequent chemotherapy and radiotherapy (OR, 1.69; 95% CI, 1.07e2.67; P ¼ 0.02), other illness that caused pain (OR, 2.37; 95% CI, 1.72e3.26; P < 0.0001), depression (OR, 2.07; 95% CI, 1.25e3.40; P ¼ 0.004), and anxiety (OR, 1.83; 95% CI, 1.26e2.66; P ¼ 0.002) were associated with chronic pain. Conclusion. Young age, previous comorbidities (such as back pain, arthritis, arthrosis, and fibromyalgia), and combined treatment with axillary lymph node dissection, chemotherapy, and radiotherapy were risk factors for chronic pain. Whether depression or anxiety is a risk factor for chronic pain remains unclear. J Pain Symptom Manage 2014;-:-e-. Ó 2014 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Address correspondence to: Inger Schou Bredal, PhD, Oslo University Hospital HF, AKBPB, Oslo 0424, Norway. E-mail: [email protected] Ó 2014 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Accepted for publication: December 19, 2013.
0885-3924/$ - see front matter http://dx.doi.org/10.1016/j.jpainsymman.2013.12.239
2
Schou Bredal et al.
Vol.
-
No.
- -
2014
Key Words Adjuvant therapy, anxiety, breast cancer, chronic pain, depression, surgery
Introduction The prevalence of chronic pain in breast cancer survivors in Norway is not known. According to literature, the prevalence of chronic pain after breast cancer treatment varies from 25% to 60% in other countries.1e5 Chronic pain is still frequently hidden by breast cancer survivors and is often neglected by health-care professionals.6,7 Many risk factors for chronic pain after breast cancer treatment have been suggested, with many possible confounding factors. The current literature shows that chronic pain is associated with nerve damage related to the surgical technique,8 adjuvant therapy (such as chemotherapy, radiotherapy, and endocrine therapy),9 and younger age.3,5 However, these findings are equivocal because there is a body of literature that found no association between chemotherapy and chronic pain.3,5 Furthermore, younger women are more likely to receive chemotherapy and to be depressed10e12 compared with older women, which may explain the association between age and chronic pain. A recent review article by Andersen and Kehlet1 regarding the risk factors of chronic pain after breast cancer treatment concluded that the findings were inconclusive, although nerve damage and radiotherapy appeared to be significant risk factors for chronic pain after breast cancer treatment. They recommended a comprehensive approach to research into chronic pain after breast cancer. To date, no study has investigated comprehensively the characteristics of breast cancer survivors who experience chronic pain, in the sense of examining all known characteristics simultaneously, including comorbidities that existed before breast cancer surgery and treatment. Chronic pain can have a significant negative impact on the health and daily life of breast cancer survivors.13e15 Thus, it is important to determine the psychosocial, medical, and surgical characteristics of breast cancer survivors with chronic pain. This knowledge will enable physicians and nurses to identify breast cancer patients who are at risk of developing chronic
pain after treatment and are likely to need intervention to prevent additional pain. In addition, survivors who might have chronic pain at follow-up could be identified and could receive pain management. The aim of this study was to identify the psychosocial, medical, and surgical characteristics of breast cancer survivors with chronic pain. In addition, we investigated the prevalence of chronic pain after breast cancer treatment nationwide, as well as its intensity and body location. Persistent pain, daily pain, or pain that occurred regularly for three or more months was defined as chronic pain.16
Materials and Methods Study Population A random sample of 1650 women aged 18e 75 years who were treated for breast cancer two to six years before the onset of the study was identified in the Cancer Registry of Norway. Each of the 10 hospitals that had treated these women received a list of the names of their patients, to evaluate if they were eligible for the study. Exclusion criteria were death, metastatic disease, cognitive impairment, serious psychiatric illness, or other malignancies. Of these 1650 women, 1364 were eligible, and a study questionnaire was sent to them between 2009 and 2010. Thirty-two of the questionnaires were returned because of unknown addresses. The questionnaires were answered anonymously. The study was conducted in accordance with the Declaration of Helsinki and was approved by the regional ethics committee. Patients were screened using the question ‘‘Do you have/have you experienced pain as a result of your operation and/or treatment for breast cancer?’’ If they answered ‘‘yes,’’ they were asked how many years or months they had experienced pain and were then asked to complete two pain questionnaires aimed at identifying various characteristics of the patients, the impact of pain on function, and pain quality. To determine which of the patients were experiencing pain currently,
Vol.
-
No.
- -
2014
Chronic Pain in Breast Cancer Survivors
only women who indicated on the numeric pain rating scale that they had had pain the previous week were categorized as still having chronic pain. All women supplied their demographic, medical, and surgical data and filled the Hospital Anxiety and Depression Scale.
Questionnaire Using a numeric pain rating scale (zero to 10), a score of one to three was rated as mild, four to seven was rated as moderate, and eight or more was rated as severe pain. Pain scores of four or more have been empirically demonstrated to affect general activity and mood and are considered clinically important for treatment.17 The Brief Pain Inventory Questionnaire. The Brief Pain Inventory was used to record the intensity of the pain experience and the presence of debilitating pain in daily life.18 It consists of 15 items, and responses are ranked on a numeric rating scale that ranges from zero to 10. These items register pain during the previous week and at present (pain severity items) and the extent to which pain affects the social life and daily activities of individuals (pain interference items). It has been validated, translated into Norwegian, and applied to cancer patients.19 The Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs. It is a seven-item scale that identifies pain of predominantly neuropathic origin based on the patient’s current symptoms and signs.20 Each item is rated via a binary response (yes or no) to present symptoms (five items) or clinical signs (two items). It includes a body map for identifying pain areas and an 11-point numeric rating scale that rates ‘‘how bad their pain has been in the previous week.’’ This phrasing is similar to that of the items of the Brief Pain Inventory. The pain is anchored on the following points: zero ¼ no pain and 10 ¼ worst pain imaginable, which results in the patient being scored out of a total of 24 points. A score of 12 or more is regarded as symptoms and signs of neuropathic pain (SSNP). The diagnosis of probable and definite neuropathic pain requires confirmatory evidence from a neurologic examination.21 The self-administered Leeds Assessment of Neuropathic Symptoms
3
and Signs is a well-validated tool of pain selfassessment. It has been translated to Norwegian using standard procedures. The Hospital Anxiety and Depression Scale. It is a 14-item scale: seven measuring anxiety and seven measuring depression.22 Each item is scored on a four-point scale (zero to three). A cutoff score of eight or more is regarded as the presence of clinically significant anxiety or depression.23 The scale has been translated into Norwegian and validated.23
Statistics The PASW Statistics 18 software (SPSS Inc., Chicago, IL) was used for statistical analyses. Patients were categorized as survivors with chronic pain or without chronic pain according to their response to the screening question. Descriptive analyses were used to identify the prevalence, intensity, localization, and quality of the pain. Between-group comparisons were made using the chi-squared test in the case of categorical variables or t-tests in the case of continuous variables. Logistic regression analyses were used to assess each of the variables separately regarding their association with chronic pain. The variables assessed were age, education level, marital status, body mass index (BMI), medical variables (surgery type and adjuvant treatment), and other illnesses associated with pain, anxiety, and depression. Subsequently, multiple logistic regression analyses were performed to assess the association between all variables identified in the univariate analysis using a liberal significance level of P < 0.2524 and chronic pain. The Hosmer-Lemeshow goodness-of-fit test was applied on the final model, in which P > 0.05 indicated support for the model. The significance was set at 5%.
Results Pain Prevalence, Intensity, and Body Location The overall response rate was 63% (n ¼ 834). Of the 834 women, 48% (n ¼ 399) had experienced persistent pain after breast cancer treatment and 41% (n ¼ 343) continued to have pain at the time of investigation. The demographic, surgical, and medical data of women with and without chronic pain are presented in Table 1. Among the women
4
Schou Bredal et al.
Vol.
-
No.
- -
2014
Table 1 Breast Cancer Survivors Demographic, Medical, and Surgical Variables Variable Age (years), mean (SD) Range Age group (years), % 25e45 46e55 56e65 66e75 BMI (kg/m2), mean (SD) Marital status % Married/cohabitant Divorced Single Widowed >12 Years of education, % Employment, % Full time Part time Full-time housewife Retired Disabled On sick leave Surgery, % Breast-conserving surgery Mastectomy (MAS) Sentinel lymph node (SLN) biopsyb Axillary dissection (ALND) Adjuvant therapy, % Radiotherapy Locoregional radiotherapy to the axillary level Chemotherapy Endocrine therapy, % Aromatase inhibitors Tamoxifen Switchedc Herceptin, % Lymphedema, %
All (n ¼ 834)
With Chronic Pain (n ¼ 343)
Without Chronic Pain (n ¼ 491)
56 (7.8) 26e74
55.2 (8.3) 26e71
58.9 (7.2) 36e74
8.9 27.7 45.9 17.5 25.1 (4.2)
58.1 50.7 34.7 34.5 25.4 (4.1)
41.9 49.3 65.3 65.5 24.9 (4.2)
71.0 12.0 11.0 6.0 43.8
71.1 11.5 12.4 5.0 47.4
70.8 12.5 10.2 6.5 41.4
38.2 20.3 1.9 13.2 17.1 9.3
32.0 25.7 2.1 8.6 21.9 9.8
37.9 23.4 1.6 15.2 13.1 8.8
67.5a 39.7 47.1 33.0
67.9 39.9 51.0 39.1
67.2 39.5 44.4 28.9
ns ns 0.05 0.001
75.6 53.2 53.2
78.1 29.2 62.3
73.8 19.8 46.9
0.03 0.016
-
No.
- -
2014
Journal of Pain and Symptom Management 1
Original Article
Chronic Pain in Breast Cancer Survivors: Comparison of Psychosocial, Surgical, and Medical Characteristics Between Survivors With and Without Pain Inger Schou Bredal, PhD, Nina A. Smeby, PhD, Stig Ottesen, MD, Torhild Warncke, PhD, and Ellen Schlichting, PhD Oslo University Hospital (I.S.B., S.O., T.W., E.S.) and University of Oslo (I.S.B., N.A.S., S.O.), Oslo, Norway
Abstract Context. According to literature, 25%e60% of women treated for breast cancer, regardless of the stage, experience pain. Many risk factors have been suggested, with many possible confounding factors. Objectives. The aim was to investigate psychosocial, surgical, and medical factors associated with chronic pain by comparing breast cancer survivors with chronic pain with survivors without chronic pain. In addition, we investigated the prevalence, intensity, and body location of chronic pain after breast cancer treatment nationwide. Methods. A nationwide postal survey of 1332 women who received surgery and adjuvant therapy for breast cancer in Norway two to six years before the onset of this study. Results. A total of 832 women (63%) returned the questionnaires, and 41% reported pain, of which 51% had mild, 41% moderate, and 8% severe pain. Among the women who experienced pain, 33.8% reported symptoms and signs of neuropathic pain. Young age (odds ratio [OR], 0.95; 95% CI, 0.93e0.98; P < 0.0001), axillary lymph node dissection with subsequent chemotherapy and radiotherapy (OR, 1.69; 95% CI, 1.07e2.67; P ¼ 0.02), other illness that caused pain (OR, 2.37; 95% CI, 1.72e3.26; P < 0.0001), depression (OR, 2.07; 95% CI, 1.25e3.40; P ¼ 0.004), and anxiety (OR, 1.83; 95% CI, 1.26e2.66; P ¼ 0.002) were associated with chronic pain. Conclusion. Young age, previous comorbidities (such as back pain, arthritis, arthrosis, and fibromyalgia), and combined treatment with axillary lymph node dissection, chemotherapy, and radiotherapy were risk factors for chronic pain. Whether depression or anxiety is a risk factor for chronic pain remains unclear. J Pain Symptom Manage 2014;-:-e-. Ó 2014 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Address correspondence to: Inger Schou Bredal, PhD, Oslo University Hospital HF, AKBPB, Oslo 0424, Norway. E-mail: [email protected] Ó 2014 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Accepted for publication: December 19, 2013.
0885-3924/$ - see front matter http://dx.doi.org/10.1016/j.jpainsymman.2013.12.239
2
Schou Bredal et al.
Vol.
-
No.
- -
2014
Key Words Adjuvant therapy, anxiety, breast cancer, chronic pain, depression, surgery
Introduction The prevalence of chronic pain in breast cancer survivors in Norway is not known. According to literature, the prevalence of chronic pain after breast cancer treatment varies from 25% to 60% in other countries.1e5 Chronic pain is still frequently hidden by breast cancer survivors and is often neglected by health-care professionals.6,7 Many risk factors for chronic pain after breast cancer treatment have been suggested, with many possible confounding factors. The current literature shows that chronic pain is associated with nerve damage related to the surgical technique,8 adjuvant therapy (such as chemotherapy, radiotherapy, and endocrine therapy),9 and younger age.3,5 However, these findings are equivocal because there is a body of literature that found no association between chemotherapy and chronic pain.3,5 Furthermore, younger women are more likely to receive chemotherapy and to be depressed10e12 compared with older women, which may explain the association between age and chronic pain. A recent review article by Andersen and Kehlet1 regarding the risk factors of chronic pain after breast cancer treatment concluded that the findings were inconclusive, although nerve damage and radiotherapy appeared to be significant risk factors for chronic pain after breast cancer treatment. They recommended a comprehensive approach to research into chronic pain after breast cancer. To date, no study has investigated comprehensively the characteristics of breast cancer survivors who experience chronic pain, in the sense of examining all known characteristics simultaneously, including comorbidities that existed before breast cancer surgery and treatment. Chronic pain can have a significant negative impact on the health and daily life of breast cancer survivors.13e15 Thus, it is important to determine the psychosocial, medical, and surgical characteristics of breast cancer survivors with chronic pain. This knowledge will enable physicians and nurses to identify breast cancer patients who are at risk of developing chronic
pain after treatment and are likely to need intervention to prevent additional pain. In addition, survivors who might have chronic pain at follow-up could be identified and could receive pain management. The aim of this study was to identify the psychosocial, medical, and surgical characteristics of breast cancer survivors with chronic pain. In addition, we investigated the prevalence of chronic pain after breast cancer treatment nationwide, as well as its intensity and body location. Persistent pain, daily pain, or pain that occurred regularly for three or more months was defined as chronic pain.16
Materials and Methods Study Population A random sample of 1650 women aged 18e 75 years who were treated for breast cancer two to six years before the onset of the study was identified in the Cancer Registry of Norway. Each of the 10 hospitals that had treated these women received a list of the names of their patients, to evaluate if they were eligible for the study. Exclusion criteria were death, metastatic disease, cognitive impairment, serious psychiatric illness, or other malignancies. Of these 1650 women, 1364 were eligible, and a study questionnaire was sent to them between 2009 and 2010. Thirty-two of the questionnaires were returned because of unknown addresses. The questionnaires were answered anonymously. The study was conducted in accordance with the Declaration of Helsinki and was approved by the regional ethics committee. Patients were screened using the question ‘‘Do you have/have you experienced pain as a result of your operation and/or treatment for breast cancer?’’ If they answered ‘‘yes,’’ they were asked how many years or months they had experienced pain and were then asked to complete two pain questionnaires aimed at identifying various characteristics of the patients, the impact of pain on function, and pain quality. To determine which of the patients were experiencing pain currently,
Vol.
-
No.
- -
2014
Chronic Pain in Breast Cancer Survivors
only women who indicated on the numeric pain rating scale that they had had pain the previous week were categorized as still having chronic pain. All women supplied their demographic, medical, and surgical data and filled the Hospital Anxiety and Depression Scale.
Questionnaire Using a numeric pain rating scale (zero to 10), a score of one to three was rated as mild, four to seven was rated as moderate, and eight or more was rated as severe pain. Pain scores of four or more have been empirically demonstrated to affect general activity and mood and are considered clinically important for treatment.17 The Brief Pain Inventory Questionnaire. The Brief Pain Inventory was used to record the intensity of the pain experience and the presence of debilitating pain in daily life.18 It consists of 15 items, and responses are ranked on a numeric rating scale that ranges from zero to 10. These items register pain during the previous week and at present (pain severity items) and the extent to which pain affects the social life and daily activities of individuals (pain interference items). It has been validated, translated into Norwegian, and applied to cancer patients.19 The Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs. It is a seven-item scale that identifies pain of predominantly neuropathic origin based on the patient’s current symptoms and signs.20 Each item is rated via a binary response (yes or no) to present symptoms (five items) or clinical signs (two items). It includes a body map for identifying pain areas and an 11-point numeric rating scale that rates ‘‘how bad their pain has been in the previous week.’’ This phrasing is similar to that of the items of the Brief Pain Inventory. The pain is anchored on the following points: zero ¼ no pain and 10 ¼ worst pain imaginable, which results in the patient being scored out of a total of 24 points. A score of 12 or more is regarded as symptoms and signs of neuropathic pain (SSNP). The diagnosis of probable and definite neuropathic pain requires confirmatory evidence from a neurologic examination.21 The self-administered Leeds Assessment of Neuropathic Symptoms
3
and Signs is a well-validated tool of pain selfassessment. It has been translated to Norwegian using standard procedures. The Hospital Anxiety and Depression Scale. It is a 14-item scale: seven measuring anxiety and seven measuring depression.22 Each item is scored on a four-point scale (zero to three). A cutoff score of eight or more is regarded as the presence of clinically significant anxiety or depression.23 The scale has been translated into Norwegian and validated.23
Statistics The PASW Statistics 18 software (SPSS Inc., Chicago, IL) was used for statistical analyses. Patients were categorized as survivors with chronic pain or without chronic pain according to their response to the screening question. Descriptive analyses were used to identify the prevalence, intensity, localization, and quality of the pain. Between-group comparisons were made using the chi-squared test in the case of categorical variables or t-tests in the case of continuous variables. Logistic regression analyses were used to assess each of the variables separately regarding their association with chronic pain. The variables assessed were age, education level, marital status, body mass index (BMI), medical variables (surgery type and adjuvant treatment), and other illnesses associated with pain, anxiety, and depression. Subsequently, multiple logistic regression analyses were performed to assess the association between all variables identified in the univariate analysis using a liberal significance level of P < 0.2524 and chronic pain. The Hosmer-Lemeshow goodness-of-fit test was applied on the final model, in which P > 0.05 indicated support for the model. The significance was set at 5%.
Results Pain Prevalence, Intensity, and Body Location The overall response rate was 63% (n ¼ 834). Of the 834 women, 48% (n ¼ 399) had experienced persistent pain after breast cancer treatment and 41% (n ¼ 343) continued to have pain at the time of investigation. The demographic, surgical, and medical data of women with and without chronic pain are presented in Table 1. Among the women
4
Schou Bredal et al.
Vol.
-
No.
- -
2014
Table 1 Breast Cancer Survivors Demographic, Medical, and Surgical Variables Variable Age (years), mean (SD) Range Age group (years), % 25e45 46e55 56e65 66e75 BMI (kg/m2), mean (SD) Marital status % Married/cohabitant Divorced Single Widowed >12 Years of education, % Employment, % Full time Part time Full-time housewife Retired Disabled On sick leave Surgery, % Breast-conserving surgery Mastectomy (MAS) Sentinel lymph node (SLN) biopsyb Axillary dissection (ALND) Adjuvant therapy, % Radiotherapy Locoregional radiotherapy to the axillary level Chemotherapy Endocrine therapy, % Aromatase inhibitors Tamoxifen Switchedc Herceptin, % Lymphedema, %
All (n ¼ 834)
With Chronic Pain (n ¼ 343)
Without Chronic Pain (n ¼ 491)
56 (7.8) 26e74
55.2 (8.3) 26e71
58.9 (7.2) 36e74
8.9 27.7 45.9 17.5 25.1 (4.2)
58.1 50.7 34.7 34.5 25.4 (4.1)
41.9 49.3 65.3 65.5 24.9 (4.2)
71.0 12.0 11.0 6.0 43.8
71.1 11.5 12.4 5.0 47.4
70.8 12.5 10.2 6.5 41.4
38.2 20.3 1.9 13.2 17.1 9.3
32.0 25.7 2.1 8.6 21.9 9.8
37.9 23.4 1.6 15.2 13.1 8.8
67.5a 39.7 47.1 33.0
67.9 39.9 51.0 39.1
67.2 39.5 44.4 28.9
ns ns 0.05 0.001
75.6 53.2 53.2
78.1 29.2 62.3
73.8 19.8 46.9
0.03 0.016
