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Secondary and tertiary prevention research often assesses and intervenes on processes that affect the cancer experience. These include health-related quality of life and medical adherence and, because there are often no reliable biomedical markers for these factors, self-report is the primary assessment method. Although we describe both quality of life and medical adherence in more detail below, self-report can be more generally improved by including collateral reports from spouses or family members and/or utilizing structured clinical interviews (rather than "paper and pencil" self-report).
Quality of life. It is well established that many cancer patients experience reduced quality of life (QoL), and that QoL has become an important outcome measure in cancer research. Reduced QoL can be identified through specific limitations in physical, role, cognitive, emotional, and social functioning. QoL decrements have been well documented among multiple populations, such as in breast (Roth, Lowery, Davis, & Wilkins, 2005 xClose
Roth, R.S., Lowery, J.C., Davis, J., & Wilkins, E.G. (2005). Quality of life and affective distress in women seeking immediate versus delayed breast reconstruction after mastectomy for breast cancer. Plastic and Reconstructive Surgery, 116(4), 993-1002.) and colorectal cancer patients (Arndt, Merx, Stegmaier, Ziegler, & Brenner, 2004 xClose
Arndt, V., Merx, H., Stegmaier, C., Ziegler, H., & Brenner, H. (2004). Quality of life in patients with colorectal cancer 1 year after diagnosis compared with the general population: A population-based study. Journal of Clinical Oncology, 22(23), 4829-4836.), among many others. Researchers often create their own QoL self-report instruments, although several published measures are available (e.g., the SF-36; McHorney, Ware, Lu, & Sherbourne, 1994 xClose
McHorney, C.A., Ware, Jr., J.E., Lu, J.F., & Sherbourne, C.D. (1994). The MOS 36-item Short-Form Health Survey (SF-36): III. Tests of data quality, scaling assumptions, and reliability across diverse patient groups. Medical Care, 32(1), 40-66.).
The Functional Assessment of Cancer Therapy (FACT-G; Cella et al., 1993 xClose
Cella, D.F., Tulsky, D.S., Gray, G., Sarafian, B., Lloyd, S., Linn, E., et al. (1993). The Functional Assessment of Cancer Therapy (FACT) scale: Development and validation of the general measure. Journal of Clinical Oncology, 11(3), 570-579.; Fairclough & Cella, 1996 xClose
Fairclough, D.L., & Cella, D.F. (1996). Functional Assessment of Cancer Therapy (FACT-G): Non-response to individual questions. Quality of Life Research, 5, 321-329.) questionnaires are a validated set of general measures (n = 3), cancer specific measures (n = 18), cancer specific-symptom measures (n = 11), treatment specific measures (n = 4), and symptom specific measures (n = 12). Evidence suggests that the FACT-G has smaller coefficients of variations and larger effect sizes compared to other commonly used tools (Cheung, Goh, Thumboo, Khoo, & Wee, 2005 xClose
Cheung, Y.B., Goh, C., Thumboo, J., Khoo, K.S., & Wee, J. (2005). Variability and sample size requirements of quality-of-life measures: A randomized study of three major questionnaires. Journal of Clinical Oncology, 23(22), 4936-4944.). In addition to patient self-reports of QoL, physician evaluations may be valuable. In particular, some evidence suggests that physician reports are more sensitive in recognizing changes in patient physical or general health than are patient reports (Sneeuw et al., 1997 xClose
Sneeuw, K.C., Aaronson, N.K., Sprangers, M.A., Detmar, S.B., Wever, L.D., & Schornagel, J.H. (1997). Value of caregiver ratings in evaluating the quality of life of patients with cancer. Journal of Clinical Oncology, 15(3), 1206-1217.). Caregiver reports may also be a complementary source of information, particularly when a patient report is judged to be less reliable (e.g., for social desirability reasons; Sneeuw et al., 1997 xClose
Sneeuw, K.C., Aaronson, N.K., Sprangers, M.A., Detmar, S.B., Wever, L.D., & Schornagel, J.H. (1997). Value of caregiver ratings in evaluating the quality of life of patients with cancer. Journal of Clinical Oncology, 15(3), 1206-1217.).
Medical adherence. Most patients with cancer receive some form of treatment (oral, chemotherapy, or radiation) as part of their regimen. In these cases, medical adherence is essential to reduce morbidity and increase longevity. Multiple approaches are used to determine whether patients are taking their prescribed medication at the correct dosage and frequency (Atkins & Fallowfield, 2006 xClose
Atkins, L., & Fallowfield, L. (2006). Intentional and non-intentional non-adherence to medication amongst breast cancer patients. European Journal of Cancer, 42, 2271-2276.), adhering to inpatient and outpatient treatments, and attending appointments. Treatment adherence can be assessed using both objective (e.g., drug levels in blood or urine) and subjective (e.g., diary, interview, or clinical interview self-report) methods.
Although evidence suggests that poor adherence is a barrier to effective treatment (Atkins & Fallowfield, 2006 xClose
Atkins, L., & Fallowfield, L. (2006). Intentional and non-intentional non-adherence to medication amongst breast cancer patients. European Journal of Cancer, 42, 2271-2276.; Hoagland, Morrow, Bennett, & Carnrike, 1983 xClose
Hoagland, A.C., Morrow, G.R., Bennett, J.M., Carnrike, Jr., C.L. (1983). Oncologists’ views of cancer patient noncompliance. American Journal of Clinical Oncology, 6(2), 239-244.; Miaskowski et al., 2001 xClose
Miaskowski, C., Dodd, M.J., West, C., Paul, S.M., Tripathy, D., Koo, P., et al. (2001). Lack of adherence with the analgesic regimen: A significant barrier to effective cancer pain management. Journal of Clinical Oncology, 19(23), 4275-4279.), treatment adherence for cancers is generally higher than for other medical conditions (e.g., diabetes, sleep disorders, pulmonary diseases; see DiMatteo, 2004 xClose
DiMatteo, M.R. (2004). Variations in patients’ adherence to medical recommendations: A quantitative review of 50 years of research. Medical Care, 42(3), 200-209.; cf. Escalada & Griffiths, 2006 xClose
Escalada, P. & Griffiths, P. (2006). Do people with cancer comply with oral chemotherapy treatments? British Journal of Community Nursing, 11(12), 532-536.). Factors related to non-adherence have also been studied. For example, among breast cancer patients, poorer adherence is related to more prescriptions at baseline (Lash, Fox, Westrup, Fink, & Silliman, 2006 xClose
Lash, T.L., Matthew, P.F., Westrup, J.L., Fink, A.K., & Silliman, R.A. (2006). Adherence to tamoxifen over the five-year course. Breast Cancer Research and Treatment, 99, 215-220.), treatment side effects or psychological distress (Demissie, Silliman, & Lash, 2001 xClose
Demissie, S., Silliman, R.A., & Lash, T.L. (2001). Adjuvant tamoxifen: Predictors of use, side effects, and discontinuation in older women. Journal of Clinical Oncology, 19, 322-328.; Hoagland et al., 1983 xClose
Hoagland, A.C., Morrow, G.R., Bennett, J.M., Carnrike, Jr., C.L. (1983). Oncologists’ views of cancer patient noncompliance. American Journal of Clinical Oncology, 6(2), 239-244.), low medication efficacy expectations (Fink, Gurwitz, Radowski, & Guadagnoli, & Silliman, 2004 xClose
Fink, A., Gurwitz, J., Radowski, W., Guadagnoli, E., & Silliman, R. (2004). Patient beliefs and tamoxifen discontinuation in older women with estrogen receptor-positive breast cancer. Journal of Clinical Oncology, 22, 3309-3315.), positive node status (Demissie et al., 2001 xClose
Demissie, S., Silliman, R.A., & Lash, T.L. (2001). Adjuvant tamoxifen: Predictors of use, side effects, and discontinuation in older women. Journal of Clinical Oncology, 19, 322-328.; Fink et al., 2004 xClose
Fink, A., Gurwitz, J., Radowski, W., Guadagnoli, E., & Silliman, R. (2004). Patient beliefs and tamoxifen discontinuation in older women with estrogen receptor-positive breast cancer. Journal of Clinical Oncology, 22, 3309-3315.), better physical functioning (Demissie et al., 2001 xClose
Demissie, S., Silliman, R.A., & Lash, T.L. (2001). Adjuvant tamoxifen: Predictors of use, side effects, and discontinuation in older women. Journal of Clinical Oncology, 19, 322-328.), and younger age (Partridge, Wang, Winer, & Avorn, 2003 xClose
Partridge, A., Wang, P., Winer, E., Avorn, J. (2003). Nonadherrence to adjuvant tamoxifen therapy in women with primary breast cancer. Journal of Clinical Oncology, 21, 602-606.). However, the extant studies of treatment adherence (particularly outside of medication regimens) have generally relied on self-reports, with little research examining the validity of patients’ self-reported adherence to cancer treatment. A necessary first step appears to be the generation of standardized definitions and instruments for treatment adherence assessments in cancer patients (Escalada & Griffiths, 2006 xClose
Escalada, P. & Griffiths, P. (2006). Do people with cancer comply with oral chemotherapy treatments? British Journal of Community Nursing, 11(12), 532-536.). In addition, researchers assessing medical compliance should include items that differentiate intentional (willful) versus non-intentional noncompliance (Atkins & Fallowfield, 2006 xClose
Atkins, L., & Fallowfield, L. (2006). Intentional and non-intentional non-adherence to medication amongst breast cancer patients. European Journal of Cancer, 42, 2271-2276.).
In short, research among cancer populations includes multiple psychosocial factors that are measured using self-report. Evidence exists for the validity of existing tools to measure quality of life. Additional methods of assessing medical adherence are needed. We will see tremendous advancements as innovative methods are developed to measure these constructs.
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