Because of the complexity of breast cancer and the diverse nature of its patient population, no one instrument is both comprehensive and sensitive enough to report clinically meaningful changes in all outcomes across all phases of care and has satisfactory respondent or provider burden. However, based on Mandelblatt's et al.  comprehensive meta-analysis of breast cancer outcomes literature, they believe it is possible to develop a "core" set of questions to measure breast cancer outcomes. After reviewing the articles retrieved in the PubMed search, 21 QOL instruments were identified as being the most used assessments within the breast cancer population. Each instrument is briefly described below and a summary of these instruments can be found in Appendix A (see Additional file 1).
Description of QOL instruments
Beck Depression Inventory (BDI) 
The BDI is a 21-item self-administered scale designed to measure depression. It has one domain, which is depression.
The Breast Cancer Chemotherapy Questionnaire (BCQ) 
The BCQ is a 30-item interviewer-administered questionnaire developed to measure outcomes of women with stage II breast cancer receiving adjuvant chemotherapy. It is comprised of seven domains (consequences of hair loss, positive well-being, physical symptoms, trouble and inconvenience, fatigue, emotional dysfunction, and nausea) .
Breast Cancer Prevention Trial Symptom Checklist (BCPT) [32, 33]
The BCPT is a 43-item self-administered questionnaire designed to examine the physical and psychological symptoms associated with menopause and Tamoxifen usage. This questionnaire is comprised of eight symptoms (hot flashes, nausea, bladder control, vaginal problems, musculoskeletal pain, cognitive problems, weight problems, and arm problems).
Cancer Needs Questionnaire – Short Form (CNQ-SF) 
The CNQ-SF is a 32-item self-administered questionnaire developed to assess cancer patients' needs. It is comprised of five domains (psychological, health information, physical and daily living, patient care and support, and interpersonal communication) .
Cancer Rehabilitation Evaluation System – Short Form (CARES-SF) 
The CARES-SF is a 59-item self-administered questionnaire developed to assess patients' cancer-related problems. The assessment is comprised of six domains (physical, psychosocial, medical interaction, martial, sexual, and global) and is scaled on a five point Likert scale ranging from 0 (Not at all) to 4 (Very much) .
Center for Epidemiologic Studies Depression Scale-10 (CES-D) 
The CES-D-10 is a short 10-item self-administered scale designed to measure depression. The 20-item CES-D is one of the most common screening tests for depression.
Edmonton Symptom Assessment System (ESAS) 
The ESAS is a 9-item self-administered questionnaire designed to measure a variety of symptoms. This questionnaire is comprised of nine domains (pain, tiredness, nausea, depression, anxiety, drowsiness, appetite, well-being, and shortness of breath) and is scaled using a visual analog scale.
European Organization for Research and Treatment of Cancer QOL Cancer Specific Version (EORTC QLQ-C30)
The EORTC QLQ-C30 is a 30-item self-administered cancer specific questionnaire designed to measure QOL in the cancer population. The assessment is comprised of nine domains (physical, role, cognitive, emotional, social, fatigue, pain, nausea and vomiting .
European Organization for Research and Treatment of Cancer QOL Breast Cancer Specific Version (EORTC QLQ-BR23) 
The EORTC QLQ-BR23 is a 23-item self-administered breast cancer specific questionnaire, usually administered with the EORTC QLQ-C30, designed to measure QOL in the breast cancer population at various stages and with patients with differing treatment modalities. The assessment is comprised of five domains (body image, sexuality, arm symptoms, breast symptoms, and systemic therapy side effects) .
Functional Assessment of Cancer Therapy – Breast Symptom Index (FACT-B – FBSI) (44 items) [45, 46]
The FACT-B – FBSI is a 44-item self-administered questionnaire specific to breast cancer patients. The assessment is comprised of six domains (physical well-being, social/family well-being, relationship with doctor, emotional well-being, functional well-being, and additional concerns) .
Functional Assessment of Cancer Therapy – Endocrine Symptom Subscale (FACT-ES) 
The FACT-ES is an 18-item self-administered questionnaire, usually administered with the FACT-B, focusing on endocrine concerns experienced during breast cancer treatment .
Functional Living Index – Cancer (FLIC) 
The FLIC is a 22-item self-administered questionnaire designed to assess the effect cancer treatment and symptoms have on functional ability in all areas of life. This questionnaire is comprised of five domains (physical functioning, mental functioning, social functioning, general health/well-being, and gastrointestinal symptoms) .
Geriatric Depression Scale – Short Form (GDS-SF)
The GDS-SF is a 15-item self-administered questionnaire designed to assess depression in the elderly. This instrument is comprised of four domains (positive mood; sad mood; boredom, memory problems, and energy level; and staying at home) .
Hospital Anxiety and Depression Scale (HADS) 
The HADS is a 14-item self-administered questionnaire developed to measure anxiety and depression. The questionnaire is comprised of two domains (anxiety and depression) .
Life Satisfaction Questionnaire (LSQ) 
The LSQ is a 32-item self-administered questionnaire developed to measure one's general sense of satisfaction with life as it relates to school, relationships, leisure time, religious practices, and overall health specifically for women with breast cancer. This questionnaire is comprised of six domains (quality of family relation, physical symptoms, socioeconomic situation, quality of daily activities, sickness impact, and quality of close friend relation) .
Medical Outcome Study's 36-Item Short Form Health Survey (SF-36) 
The SF-36 is a 36-item self-administered questionnaire developed to assess health-related QOL. It is comprised of eight domains (physical functioning, role limitations due to physical health, role limitations due to emotional problems, energy/fatigue, emotional well-being, social functioning, bodily pain, and general health) .
Rotterdam Symptoms Checklist (RSCL) – Modified
The RSCL-Modified is a 28-item self-administered questionnaire developed to assess symptom-related distress among cancer patients. This instrument is comprised of two domains (physical distress and miscellaneous variables) .
Satisfaction with Life Domains Scale for Breast Cancer (SLDS-BC)
The SLDS-BC is a 32-item self-administered questionnaire comprised of five domains (social functioning, appearance, physical functioning, communication with medical providers, and spirituality) .
Spitzer Quality of Life Index (QL-Index)
The QL-Index is a 5-item interviewer-administered or self-administered questionnaire designed to assess health outcomes of those with cancer and other chronic diseases. The questionnaire is comprised of five domains (activity, daily living, health, support, and outlook) .
World Health Organization Quality of Life – Brief Version (WHOQOL-BREF) 
The WHOQOL-BREF is a 26-item self-administered assessment designed to examine domain level profiles assessing quality of life. This assessment is comprised of four domains (physical health, psychological, social relationships, and environment) .
Zung Self-Rating Depression Scale (SDS) 
The Zung SDS is a 20-item self-administered scale designed to measure depression .
Benefits of QOL assessments
Overall benefits of QOL assessments
The overall benefits of QOL assessments include their use in preventive intervention and their potential to inform clinicians about the patient's illness as well as how certain treatments may affect the QOL of that patient. Jacobsen et al. report that an understanding of QOL also improves communication between physicians and patients . Evaluation of the advantages of QOL assessments has led the National Institutes of Health and the National Cancer Institute to conclude that QOL measures should be incorporated into research studies when possible.
Benefits of QOL assessment in clinical practice
Magruder-Habib et al.  and Rubenstein et al.  reported significantly more changes to treatment in the intervention group, participants who were assessed using a QOL instrument, as compared to the control group, who were not assessed. In one study, physicians took more action on the patient-reported categories listed in the chart of the experimental group as compared to the control group (73% and 68.5%, respectively) . Gold and Baraff  and Mazonson et al.  reported significantly more referral rates to other professionals in the intervention group as compared to the control group. One study reported that physicians found the questionnaires to be more useful for those patients who had a worse initial functioning score .
In a study by Detmar et al. , almost 97% of the patients stated that the QOL profile provided an accurate summary of their functioning and well-being. Fifty-seven percent reported their physicians used the profile explicitly during their visits, 79% believed the profile enhanced physician awareness of their health problems, and 87% thought it would be useful to introduce a QOL assessment as a standard part of the outpatient clinical experience. With regard to the length of time for an office visit, this study did not find statistical significance in the length of office visit; however, the control group visits took longer than the intervention group (20.4 minutes vs. 19.8 minutes, respectively) .
Role of QOL assessment in facilitating communication
A study conducted by Mazonson et al.  reported an increase in patient-physician communication in the intervention group as compared to the control group. Wagner et al.  found a moderate percentage (67%) of patients reported positive attitudes about completion of the assessment as well as sharing their feelings and physical abilities with their physician. Furthermore, the study reported that more patients wanted physicians to inquire about their feelings (80%) as opposed to their physical abilities (71%). Street et al.  reported that most patients wanted physicians to inquire about their vitality, physical functioning, and role limitations due to physical issues, and only half of the patients felt that these problems were currently being discussed. Other studies reported that at least a moderate percentage of physicians said that they had made changes within their practice since the implementation of a QOL instrument [70–72].
Studies have reported that QOL issues in intervention groups were discussed significantly more frequently when QOL assessments, specifically the EORTC-C30, were used compared to control groups (no QOL assessment used) [68, 73]. Taenzer et al. revealed that patients reported 49% of the QOL items they identified were addressed by their physician during their clinical visit . In Detmar et al. , 10 of the 12 QOL issues were discussed more frequently in the intervention group; however, only three issues reached statistical significance: social functioning, fatigue, and dyspnea. Intervention group physicians were able to identify a larger percentage of patients with moderate to severe QOL issues, such as problems with daily activities, feelings, social activities, pain, and fatigue, compared to the control group's physicians, who only could identify problems in daily activities and pain. The most noteworthy increase was the discussion of less observable issues, such as social functioning, or those that are more diffuse and long-term in nature, such as fatigue, that are usually left unaddressed by physicians .
In the same study by Detmar et al. , patients in the intervention group received significantly more counseling from their physicians on how to manage their health problems than did the control group. In examining patient satisfaction, the only statistically significant difference between the two groups was shown for the amount of emotional support received, with the intervention group receiving more than the control group. Overall, patients in the intervention group exhibited a statistically significant improvement over time in regards to mental health and role functioning. All of the physicians stated that the profiles offered a useful overall representation of their patient's health-related experiences and indicated that it also assisted with communication, particularly in regards to psychosocial topics and "unexpected" symptoms such as sleep disturbances .
Role of QOL assessment in clinical decision-making
Bendsten et al. reported that physicians have reported that a holistic approach, including QOL, is necessary when treating patients . Greenhalgh and Meadows, Di Maio and Perrone, and Le et al. have found that one important benefit of QOL assessment is to encourage shared decision making and to facilitate communication between physicians and patients[25, 75, 76] by providing feedback to the patients regarding their progress, goals, and expectations . According to Donaldson as well as Deyo and Carter, QOL measures can also be used for monitoring disease progression (i.e., survival) or response to treatment (i.e., toxicity, side effects, and adverse effects) [18, 77]. Other potential benefits of QOL measurement include detection of treatable issues that are normally overlooked during patient care such as education about the disease and nutritional counseling as well as obtaining a baseline upon entering care or therapy. QOL measurement could potentially be helpful in monitoring a reduction of functional capacity and in identifying other physical and emotional problems. Donaldson as well as Bendsten et al. and Le et al. have found that timely feedback can result in a reduction in anxiety, thus preventing fewer visits and calls with improved satisfaction with care [18, 74, 76]. If patients were to take on the role of more self-management with the use of QOL assessment's implementation, it could lead to more efficient use of resources, and thereby reduce costs .
Detmar et al.  (2002) discovered that even though all of the physicians reported they would like to continue using QOL assessments in their daily practice, several suggested the need for more tailored assessments to specific patient groups, such as the site of pain and use of pain medication for patients with bone metastases . Another study by Middeke et al. found that all the participating physicians reported the QOL profiles were easy to understand and clinically relevant, and more than half of the physicians indicated the profiles had provided them with additional information that led to a more complete diagnosis .
Treatment plans can also be altered or contingent upon an individual's QOL. Di Maio and Perrone  found that elderly cancer patients prefer treatments that potentially improve their QOL over that of their survival; only 22% chose chemotherapy if a hypothesized survival benefit of three months was given, and 68% chose chemotherapy if it would substantially reduce symptoms, even if no significant increase in survival was expected.
Benefits of non-visit based assessment platforms
A study by Donaldson revealed that the Internet, computers, telephones, and hand held devices now allow QOL assessment to become non-visit based. These platforms provide a highly efficient, timely, and individualized approach to QOL assessment, and provide better privacy and confidentiality.
By allowing patients to complete password-protected QOL assessments whenever they are away from doctors' offices and are experiencing symptoms, patients may submit their reports at any time of the day. PRO reports submitted during the day can be reviewed immediately by physicians, and those submitted after office hours would be viewed the next morning. By evaluating PRO reports, physicians may triage patients to determine which cases are most urgent and to decide on appropriate treatment customized for each patient. Triage is usually performed by using a threshold score, with people above the determined score to be given more urgent care. These methods also allow for ongoing monitoring of patient treatment and management to evaluate their effectiveness .
Acceptability of QOL assessments
Healthcare providers and patients alike find QOL assessments acceptable in helping breast cancer patients to overcome areas of QOL that have been affected by the disease. Several studies have demonstrated the reasons why the implementation of QOL assessments is found acceptable by physicians.
Healthcare provider acceptability
Finlay and Dunlap as well as Bezjak et al. report that healthcare providers agree that QOL assessments are valuable in clinical practice [26, 28]. Bezjak et al (2001) conducted a survey of 271 Eastern Cooperative Oncology Group (ECOG) physicians and found that 94% of respondents disagreed with the statement "I do not plan to incorporate QOL data in my practice." In addition, 75% disagreed with the statement "I would only be willing to use formal QOL assessment if required to do so by my institution or regulatory body." Eighty-two percent indicated it was likely that they would increase their use of QOL in the care of future patients .
Several studies, including those done by Wagner et al., Wasson et al., and Moore et al., have reported at least a moderate percentage of physicians had positive attitudes about the implementation and feasibility of QOL assessments within routine practice [24, 70, 80]. Moore et al.  and Rubenstein et al.  showed a large percentage of internists and family physicians reported the QOL information as accurate and would use the instrument with other patients in the future. Other studies examined the physician's perception of the efficacy of the measures in routine practice. All of them found at least a moderate percentage of physicians who showed positive attitudes [24, 70–72, 80, 81].
Another study by Taenzer et al. found an overwhelmingly positive response from oncology nurses regarding the usefulness of a computer-administered questionnaire's generated report, with 91% stating the report indicated appropriate concerns, 91% stating it guided the clinical interaction, 82% stating it promoted communication, and 74% stating the report indicated areas of need for the patients . Velikova reported that when assessing the oncologists' checklists, it was found the clinicians thought the health-related QOL information was very useful in 43% of the visits, somewhat useful in 28% of the visits, a little useful in 21% of them, and not useful in 9% of the visits .
Stiggelbout et al.  found that it was feasible to use questionnaires to evaluate patients' feelings regarding quality of life versus quantity of life. Apolone et al.  examined the acceptability of QOL questionnaires among patients and found the response rate was 64% with few missing items on the questionnaires. These results provide an example of the acceptability of QOL questionnaires for patients, and the EORTC QLQ-C30 in particular for this study .
To be acceptable, questionnaires must be sensitive to the needs of patients. Cancer patients found assessments that asked questions in the form of words rather than only numbers and had fewer answer options to be acceptable. Additionally, studies by Pijls-Johannesma et al. have revealed that questionnaires that did not ask questions that were overly personal, sensitive, or irrelevant were favored by respondents .
Problems with QOL assessments and barriers to implementation
Morris et al.  found that although 80% of healthcare professionals believed that information obtained from QOL assessments is valuable, fewer than 50% of them implemented QOL assessments in their practice. The researchers attributed the problems to an unwillingness of physicians to use the assessments because they are considered unnecessary, the belief of some practitioners that they do not have appropriate instruments, and logistical problems such as limited resources and time .
Problems due to characteristics of QOL assessments
Even though QOL information is clinically valuable, physicians often view it as providing "soft" data that does not permit "hard" measurement such as that obtained in the laboratory. Barriers to implementation can also arise due to the types of questions asked. Questions that are too personal, sensitive, or irrelevant are more likely to be omitted by respondents. For example, some questionnaires ask respondents about their careers. Pijls-Johannesma et al. report that such questions are irrelevant in the elderly population, as many respondents are retired .
Problems with implementation related to patient population
Potential problems with QOL assessments can occur prior to their implementation in clinical practice. Few studies have yet assessed QOL on long-term survivors (greater than 5 years after diagnosis), as most assess patients one year after diagnosis. It is necessary to include long-term survivors who are willing to participate in the study so that their views can be fully integrated into the initial instrument development.
Particularly in the elderly, QOL assessments can be difficult to incorporate into a clinical practice because there are a higher rate of illiteracy, worse compliance with questionnaires, cognitive disorders, comorbidities, and non-validated instruments within this population. Di Maio and Perrone  found a decrease in compliance in the elderly, as only 21.5% of the elderly patients completed the QOL questionnaire administered after six months, whereas 37.2% of younger patients completed the questionnaire. As mentioned above, Detmar et al.  did not find any significant difference in the length of time between the control visit and the intervention visit.
Problems with implementation related to their use by healthcare professionals
Findings by Deyo and Carter reveal that physicians are less familiar with QOL assessments than with imaging or physiological tests and often are unfamiliar with how to interpret the results or respond to them . Limited time is often mentioned as one of the problems associated with utilizing a QOL assessment in daily practice; however, one study by Maguire et al. found that it only took an average of 60 seconds longer for the physician to extract all of the patient's current problems .
Problems with implementation due to logistical and resource constraints
Gotay et al. state that other barriers to implementation of QOL assessments include staff and financial limitations with respect to the amount needed to produce high-quality data, quality control, monitoring procedures, data collection, and submission . Some researchers believe that interviews or semi-structured interviews conducted by professionals should be used instead of self-assessments to minimize the amount of missing data .
As reported by Velikova et al. and Allenby et al., QOL measures traditionally are collected by printed self-report questionnaires and entered into a database manually [16, 90], which, according to McDonald and Barnett, is still the most commonly used method [91, 92]. A study by Le et al. revealed that this method, however, is fraught with high labor costs, poor turnaround time, and errors . Fairly recently, optical mark-recognition systems have been developed to enhance the transfer of the data into databases. This form of input can process a large amount of data and is practical for mailed questionnaires. Nevertheless, this system has problems, such as requiring special forms, recognizing multiple answers, missing data, and examining the database for errors. Velikova et al. and Allenby et al. report that more recently, electronic means of administering QOL assessments have been introduced which combat some of the problems associated with the printed forms and optically read systems. Results are compiled automatically in the database and are available in real time for clinical use [16, 90].
Computerized QOL assessments have several advantages. They provide more accurate results, and as such, represent a picture of patients' QOL more clearly. Additionally, the use of technology to facilitate the implementation of QOL assessments increases efficiency and allows utilization by a wider population.
According to a study by Buxton et al., a touch-screen computerized system has advantages over paper-and-pencil QOL questionnaires, which include the ability to increase the font size for those with visual difficulties, reduce the number of missed items, decrease the need for paper, analyze the patient's information immediately, and easily store and retrieve the data . Allenby et al. report that electronic completion of QOL questionnaires also can reduce the potential of errors with after-survey data input and can reduce the length of time it takes to administer the questionnaires . Taenzer et al.  found patients took an average of 8.6 minutes to complete an electronic version of the EORTC QLQ-C30 questionnaire as opposed to 11 minutes to complete its paper version. In another study by Velikova et al. examining the difference between the electronic version of the EORTC QLQ-C30 and its paper version, patients took less time to complete the touch-screen version (8.3 minutes) as opposed to the paper version (9.6 minutes) . Bliven et al. state that the Internet allows for the collection of patient-reported data at multiple locations, at frequent time intervals, and at little cost . It is also reported by Le et al. that touch screens or pen-based computers are appealing because they are portable and do not require the respondents to use a keyboard or a mouse .
In a study by Velikova et al. comparing the touch-screen versions and paper versions of the EORTC QLQ-C30 and the HADS, the quality of the data extracted from a touch-screen version was found to be excellent, with no missing or problematic responses, mainly because the patient could not progress through the questionnaire without answering each question. In contrast, 1,032 errors were reported from the paper version; 357 being patient related errors (such as missing responses, multiple answers, or changed answers) and 725 being scanner related errors (such as not recognizing the responses). More than 92% of the optically read questionnaires had scanning, verification, or database errors, which caused significant additional work for the research staff who had to check and verify the quality of the database after each scanning of the paper questionnaires . The same study found that 52% of the patients surveyed preferred the touch-screen computer, compared to 24% preferring the paper version. Overall, 76% of all patients found the computer version to be acceptable (either preferring it specifically or finding it as acceptable as the paper version). Administration preference was not found to be related to age, gender, order of presentation, or time for completion .
In one study by Allenby et al., patients reported the touch-screen system to be very easy to use in regards to their ability to read the screen (95% of the patients), entering of an identification number (76%), following the instructions (74%), and choosing the appropriate answer (71%) . In another study, 99% of patients found the touch screen easy to use, 98% stated the instructions were easy to follow, 98% stated the questions were easy to read on the screen, and 99% stated the time it took to complete the survey was acceptable .
Another study by Taenzer et al. found 41% of women liked computer-administered questionnaires, 45% were neutral, and 14% said they did not like such questionnaires. If participants had prior experience with the program, their attitudes towards the computer-administered questionnaire changed, with 80% stating they liked the method, 11% stating they were neutral, and only 8% stating they did not like the method . Similarly, Newell et al. reported that 89% of oncology patients stated they would be willing to fill out a subsequent touch-screen questionnaire, with 73% of those patients being over the age of 50 and 59% having never used a computer before the assessment . Bliven et al.  found that in spite of nearly half of the respondents stating they had no prior computer experience, computer literacy was not significantly associated with the respondent's ability to complete successfully the computerized questionnaire.
A study by Velikova et al. that examined the use of computer technology in QOL assessments found that primary outcomes on the FACT-G  showed a significant improvement in the intervention group, who completed the EORTC QLQ-C30  and the HADS  on a touch-screen computer in the clinic and received feedback from the physician, as compared to the control group, who did not complete questionnaires before the visit. With further analyses, a significant improvement was also detected between the attention-control group, who completed the questionnaires but did not receive any feedback from the physician and the control group. In examining emotional well-being, the intervention group showed a higher score than the control. No difference was found, however, between the attention-control and control groups. Those patients who decided not to complete the study had a significantly lower FACT-G score at baseline than patients who finished the study. A sizeable percentage of patients in the intervention group had significant improvement in QOL after only three visits. The average number of visits needed for one person to benefit was 4.2 .
In examining the transcripts of the visits in the above-mentioned study, it was found that the intervention group had a higher number of EORTC QLQ-C30 symptoms being discussed than the control group. More discussion of chronic symptoms, such as difficulty sleeping, lack of appetite, and fatigue were observed without extending the visits. When QOL data were discussed with patients during their third visit, the mean change of the FACT-G score was higher than when QOL data were not mentioned .
Problems with computerized assessment
Velikova et al. found that patients had difficulty with the handheld computers because of the small screens as well as the software design, which prevented the patients from changing their answers. The handheld computers also had technical difficulties resulting in unreliable downloaded data and administrative problems in ensuring the security of the portable computers and the data contained within them . Entering the demographic information on the touch-screen computer was difficult and time consuming because if patients made a mistake, they would have to delete their responses and start again.
Another study by Buxton et al. found 23% of patients had problems using the touch-screen because of its lack of appropriate responsiveness to touch due to the wearing-down of equipment towards the end of the study . It would be of importance to include potential users of QOL assessments from the beginning to determine confounding issues and correct them before implementation of the system.