In a survey of local-stage prostate cancer patients, preference for prostatectomy was influenced by perceptions of its efficacy and personal burden versus nonsurgical options.
Objective: To assess factors that may influence men’s preference for surgery versus nonsurgical options among newly diagnosed patients considering treatments for local-stage prostate cancer.
Study Design: Prostate cancer patients were approached at urology clinics after diagnosis but prior to starting treatment in California, South Carolina, and Texas. Using a survey about the treatment decision-making process, patients were asked about their likes and dislikes of 5 common treatment options: surgery (prostatectomy), brachytherapy, external beam radiation therapy, hormone therapy, and watchful waiting.
Methods: Logistic regression identified associations between treatment characteristics and choice of prostatectomy compared with nonsurgical options, controlling for demographic, clinical, and psychological covariates.
Results: Of the 198 eligible men who returned the baseline survey, 59% indicated they only considered surgery and 41% considered at least 1 nonsurgical option. In multivariate analysis, patients who thought treatment efficacy was a primary concern were significantly more likely to prefer surgery only (odds ratio [OR] = 6.20, 95% confidence interval [95% CI] = 1.74, 22.10); those indicating concern about personal burden were significantly more likely to prefer nonsurgical options (OR = 0.07, 95% CI = 0.02, 0.22). Advice of friends and relatives and concerns over side effects were not significantly associated with preference for surgery versus other treatments.
Conclusions: Men’s perceptions about treatment efficacy and the personal burden of treatment dominated preferences for surgery versus nonsurgical options. Interventions to aid treatment decision making should account for these elements to minimize the impact of physician biases and patient misperceptions on men’s decisions as how best to manage their prostate cancer.
(Am J Manag Care. 2010;16(5):e121-e130)
We conducted a multisite survey of men with local-stage prostate cancer to understand their preferences for available treatments. The most influential factors were perceptions of efficacy and personal burden of prostatectomy relative to nonsurgical options.
Most men with prostate cancer are diagnosed at early stage and have several treatment options available, including prostatectomy, external beam radiation therapy, brachytherapy, and watchful waiting. Overall survival following any management choice approaches 99% at 5 years.1 A recent review found no compelling evidence favoring one approach versus another.2 Despite the lack of consensus about treatment, prostatectomy is commonly selected by men with early-stage prostate cancer, particularly those with low-risk disease.3,4 The reasons for this preference are unclear. To understand why men favor prostatectomy versus other options, we conducted a prospective survey of a diverse sample of men. Participants included men newly diagnosed with local-stage prostate cancer who were considering their treatment options.
We based our model on the taxonomy described by Holmboe and Concato, who categorized treatment attributes (likes and dislikes) into 4 axes: (1) external information, (2) intrinsic characteristics of treatment, (3) personal impressions, and (4) economic concerns.5 Using this taxonomy, we conducted focus groups with prostate cancer patients to develop relevant attributes for each management approach (including watchful waiting) that patients considered important. Based on our focus groups and literature review, we grouped characteristics into 5 domains: personal beliefs, treatment efficacy, others’ experience, personal burden, and avoiding side effects (see the Appendix).
We hypothesized that patients who indicated treatment efficacy as a main concern would be more likely to prefer prostatectomy only. Second, we hypothesized that men who indicated that a personal belief influenced their decision (for reasons other than perceived efficacy) would favor surgery because perceptions about curing other common cancers involve removing the tumor (eg, breast cancer). Third, persons who listed avoiding side effects as highly important to their decision would be less likely to prefer prostatectomy, as surgery has been associated with higher rates of incontinence and impotence compared with other options.6 Fourth, men who were influenced by the experience of a family member or friend with prostate cancer who had surgery would be more likely to prefer prostatectomy versus nonsurgical options. Patients who have undergone surgery have been reported to be strong advocates for surgery,7 and many men choose surgical options, which increases the “exposure” to this management option. Finally, we hypothesized that patients concerned with the personal burden of a treatment would prefer nonsurgical options because of the family and time burdens associated with recovery and managing a catheter. We also examined associations between treatment choice and general physical and emotional quality of life, prostate-specific symptoms, and the beliefs/perceptions patients had about prostate cancer and treatment.
Survey Development: Focus Groups and Cognitive Interviews
To develop questions that reflected the conceptual model, we conducted focus groups and cognitive interviews. Participants were identified through the Puget Sound Cancer Surveillance System, the Surveillance, Epidemiology and End Results (SEER) cancer registry for Western Washington State. Sampling randomly from SEER records for 2 urban counties, we contacted men diagnosed with local-stage prostate cancer within 6 months prior to the sampling date. Following physician notification to 69 patients, 14 men agreed to participate. Prior to the focus groups, participants received a set of likes and dislikes about treatment options based on the conceptual model.5,8-17 During the discussions, focus group participants ranked likes about the treatment they received and dislikes about treatments they did not select. Based on focus group feedback, we reduced the items in the final survey to 10 reasons (likes) for considering each treatment and 14 reasons (dislikes) for not considering a treatment. Survey items listing reasons for considering a treatment included doctor recommendation and opinions that the treatment would be more effective, have the fewest side effects, or have the least impact on the patient’s life. Survey items listing reasons for not considering a treatment included the converse of the previous 3 items and insurance not covering the treatment or out-of-pocket costs being too high. See the Appendix for the complete list.
We also included items from previous surveys developed for prostate cancer patients as well as surveys assessing general health,18,19 cancer worry,17,20,21 and trust in the healthcare system22 (see the Appendix). Using identical patient recruitment methods, these questions and the revised items were presented to 9 men in one-on-one cognitive interviews. The objectives were to confirm that patients understood the survey items and to assess survey fatigue. During the cognitive interviews, the participants completed semifinal versions of the survey while discussing the responses with an interviewer.
Participants were recruited through informed consent procedures approved by an institutional review board and were reimbursed $25 for their involvement.
Patient Population and Recruitment
Patients were recruited for the Family And Cancer Therapy Selection (FACTS) study. This study was initiated to understand the full range of domains involved in decision making by patients and partners, and how they make prostate cancer treatment decisions together. Newly diagnosed patients were approached in urology clinics at 3 sites: the Medical University of South Carolina (the University Urology Department and Ralph H. Johnson Veterans Administration Medical Center, Charleston), the University of Southern California (3 university-affiliated medical centers in Los Angeles), and the University of Texas Health Science Center at San Antonio (University Physicians Group and Audie Murphy Veterans Administration Hospital). Eligible patients included those diagnosed with local-stage disease (prostate-specific antigen [PSA] <50; tumor, node, metastasis [TNM] stages T1-T2, N0, M0) who had not initiated treatment other than hormone therapy at the time of approach. Clinic study coordinators reviewed lists of newly diagnosed local-stage prostate cancer patients scheduled for clinic visits. Interested patients signed consent forms and received a take-home survey to return by mail. Patients who indicated they had started treatment prior to the survey return date were excluded from this analysis (n = 42).
Study materials were approved by the institutional review board at each accrual site and the coordinating center. Participants received $25 after completing the baseline survey.
We conducted bivariate analyses of the relationships with each covariate and the primary outcome “preferring surgery only versus preferring at least one nonsurgical option.” We collapsed the outcome variable rather than keep individual nonprostatectomy categories because of the small number of observations in the nonprostatectomy categories. Chi-square tests were used for all categorical variables, and t tests were used to assess bivariate relationships for continuous variables. We used logistic regression to assess the association between our hypothesized likes and dislikes, and preferring only surgery versus nonsurgical options, adjusting for the demographic, clinical, and patient psychological factors noted in the Results section. We used a fixed-effects model, including recruitment site as the fixed effect in the model. This allowed for a withinsite assessment of the other variables. One limitation of this approach is the potential for other, unmeasured variables to confound the primary association between the outcome and our hypothesized likes and dislikes. Adjusting for the demographic, clinical, and patient psychological factors in the Results section addressed confounding to some extent. However, we recognize that there may be variables we were not aware of that could affect our results. The Hosmer-Lemeshow goodness-of-fit test was used to assess the overall adequacy of the model. All variables were retained in the model to assess their joint association on the outcome. For the continuous variables including the cancer worry scale,17,20,21 the cancer control scale,23 the Health System Distrust scale,22 the Expanded Prostate Index Composite scores,24,25 and the SF-12 scores,26-28 nonparametric smoothing was used to assess the unadjusted functional form between each of these variables and choice of surgery. For all these variables, the functional form was approximately linear; thus, each of these variables was entered linearly into the logistic regression model. No adjustments were made for multiple tests. All tests for statistical significance used a P value of .05.
A total of 423 patients were approached for participation. Of these, 240 met eligibility criteria and 198 (83%) returned the survey prior to initiating treatment; the analysis included the 198 patients (Figure). The median time from diagnosis to participant survey return was 70 days. The average age of the patient at the time of diagnosis was 63.0 years (SD = 8.1 years) and 36% were under the age of 60; 71% were white, 59% were employed, and 48% were college graduates (Table 1). Eighty-six percent had a PSA level of <10, 62% had a Gleason score of <6 at diagnosis, and 55% were categorized as low risk based on the combination of these factors.29 Thirty-six percent listed 2 or more noncancer comorbidities at diagnosis (Table 1).
Overall, 116 (59%) patients indicated they were considering only surgery. More than three-quarters (76%) of all patients were only considering a single treatment option, with 12% considering 2 treatments, 8% considering 3 treatments, and 2% considering 4 or 5 treatment options. We examined all options considered by patients, including those considering multiple options: 71% reported they were considering prostatectomy, 19% brachytherapy, 15% external beam radiation therapy, 15% watchful waiting, and 8% hormone therapy (data not shown).
On bivariate analysis, men preferring prostatectomy only were more likely to be less than 70 years old, have private insurance, be married, and be employed compared with those considering at least 1 nonsurgical option (Table 1). Men preferring prostatectomy scored higher on the SF-12 physical component, but not the mental component, than patients preferring other options. Sexual function was significantly higher for men preferring prostatectomy only (Table 1).
The survey domains were commonly ranked as important to the treatment decision. Nearly half (45%) of the patients considering nonsurgical options reported personal burden as important to their decision compared with 10% of men only considering surgery (Table 2). The experience of others was more likely to influence men considering surgery only. Both groups listed avoidance of side effects and personal beliefs nearly evenly in their likes and dislikes about treatment options; treatment efficacy was more commonly listed by surgeryonly men as important to their decision (see the Appendix).
Men preferring prostatectomy only were no different from those preferring other options regarding their trust in the healthcare system, levels of prostate cancer anxiety and worry, and feelings of cancer control and self-efficacy (Table 2). For those preferring prostatectomy only, there was no significant difference in the likelihood of receiving multiple different treatment recommendations compared with men considering other options.
Men concerned about the personal burden of treatment were significantly more likely to prefer nonsurgical options, and men who gave weight to the experiences of others were more likely to prefer prostatectomy only. Those concerned with treatment efficacy were significantly more likely to consider only prostatectomy. There were no significant differences in preferences for prostatectomy or nonsurgical options between those who indicated that personal beliefs or avoiding side effects was a key factor in their treatment decision.
Of the hypothesized likes and dislikes explored in the multivariate logistic regression analysis, treatment efficacy and personal burden remained strongly associated with treatment preference after adjusting for demographic, clinical, and psychological factors (Table 3). The experience of others was not significantly associated with treatment preference. Those who indicated that treatment efficacy was a main reason for their treatment choice were significantly more likely to prefer surgery only (odds ratio [OR] = 6.20, 95% confidence interval [95% CI] = 1.74, 22.10). Those who considered personal burden a top reason for their treatment preference were much less likely to prefer surgery (OR = 0.07, 95% CI = 0.02, 0.22). General and prostate-specific measures of quality of life were not significantly associated with preferring surgery only. In the multivariate model, Hispanics and Asians were more likely to only consider surgery compared with whites (OR = 10.77, 95% CI = 1.77, 65.33).
Table 4 lists the top reasons for considering and not considering each treatment choice. Patients considering brachytherapy most often believed it had the fewest side effects. The most common reason stated by those considering external radiation was research they had done on their own. The most common reason men stated for not considering prostatectomy, brachytherapy, external radiation, and/or hormone therapy was that the doctor recommended other treatment(s) (Table 4). The most common reason for not considering watchful waiting was fear about the cancer spreading.
To better understand the decision-making process for men who have been diagnosed with local-stage prostate cancer, we conducted a prospective, multicenter study of patients prior to initial therapy. We asked participants to report the management options they were considering and their reasons for liking and disliking each option. Our primary aim was to identify differences in likes and dislikes that influence treatment choice, focusing on differences between men preferring prostatectomy only and men preferring at least 1 nonsurgical option. Approximately 59% of men preferred only prostatectomy. We identified 2 strong influences on patient preferences. First, men who cited a strong concern for treatment efficacy were significantly more likely to prefer surgery. Second, men concerned with personal burdens of treatment were significantly more likely to prefer nonsurgical options. Notably, factors including disease risk among this population with local-stage cancer, side effects, and quality-of-life considerations did not emerge as strong predictors of preference for or against only considering surgery.
Prior studies of prostate cancer decision making surveyed men weeks to months after they had started or completed therapy.5,7,9,30,31 The FACTS study is unique because men provided insight into their treatment preferences as they were making their decision. A second feature of our study is our attempt to include a racially diverse cohort. Interestingly, we found that Hispanics and Asians, both of whom have a lower likelihood of prostate cancer than whites and blacks, are much more likely to prefer surgery only. This finding is consistent with a study of Hispanic men by Denberg and colleagues, who found that Latinos received prostatectomy more often than whites.32 We are not aware of studies of decision making among Asian men.
Many men in our sample appeared to believe that prostatectomy has superior efficacy compared with other options. This finding has been observed in multiple studies among men who were asked to recall reasons for their treatment choice,8 but is not consistent with current evidence.2 In contrast to our hypothesis about side effects and decisions, and despite evidence showing differential risk for side effects among management options,6 we found that concern about side effects appeared not to influence men’s preferences for surgery and consideration of nonsurgical options. This finding, combined with the apparent positive relationship between men’s concern about efficacy and preference for prostatectomy, suggests that many men have either limited access to or a poor understanding of the evidence regarding management options for local-stage prostate cancer. To address this issue, medical professionals who support prostate cancer patients during their decision process may need to take additional measures to ensure patients have a clear and balanced picture of the risks and benefits of all management options. Decision aids (eg, online or in the form of DVDs) have been shown to help patients make more informed decisions about treatment.33,34
Many men in this study expressed concern with the impact of treatment on daily life (ie, personal burden). Perceived treatment burdens had a substantial negative impact on patients’ willingness to undergo prostatectomy. Holmboe and Concato also found burden of treatment to be a powerful factor in treatment decision making.5 Gwede and colleagues noted that persons who chose options other than prostatectomy cited burden issues as reasons to avoid surgery.35 These findings may explain the recent popularity of robotic prostatectomy, which has been touted to reduce recovery time compared with open prostatectomy.36
The results of the multivariate analysis did not support our hypotheses regarding the influence of affected friends or family members on patients’ decisions. In contrast to our study, Diefenbach and colleagues found that the influence of fellow patients was second only to physicians in the decision process.15 It is possible that our sample included men who were different in some respects from men in prior studies and who were less likely to consider the opinions of friends and family. This possible difference may be due to the academic environment of our study sites, where second opinions are common.
We note some limitations of the FACTS study. We conducted it in academic urology clinics in 3 states. Although there was considerable diversity in this sample, our findings may not be generalizable to other settings. Additionally, many of the men in the sample (56%) were seeking second opinions. Our sample, therefore, may include a cohort of self-selected men with a preference for surgery. Although this factor was not an important predictor of surgery preference in the multivariate model, we acknowledge that our findings may be unique to urology settings with many patients seeking a second opinion. Second, although all patients were approached prior to treatment and the majority of men in our study returned their surveys prior to starting therapy, a portion returned surveys after initiating treatment. Although we excluded from the analysis men who had started treatment, it is possible that men who received treatment soon after diagnosis may have different perceptions than men who completed the survey prior to treatment. Third, a substantial proportion of our participants favored prostatectomy as their sole treatment consideration, thus limiting our statistical power to detect differences among the various nonsurgical treatments. We did not differentiate between robotic or open surgical procedures. Future studies of patient decision making could oversample patients considering nonsurgical options to better delineate differences between those management strategies. Although we observed differences in beliefs about treatment efficacy and personal burdens, we did not specifically measure patient knowledge about prostate cancer treatment. Future studies should examine whether inaccurate perceptions about treatment persist among men who receive accurate information, as measured by consistency in knowledge about treatment outcomes.
Patients’ personal beliefs about the value of one treatment versus another, as well as their assessments of the efficacy, burden, and side effects of various treatments, are influenced by several factors. These factors include their doctor’s advice and information available through a variety of other sources such as pamphlets, books, and the Internet. Further research is needed to characterize what leads to men’s likes and dislikes of various treatment choices. In particular, the content of the physician—patient interaction and its influence on patient considerations need further evaluation.
The authors gratefully acknowledge the contributions made by Catherine Fedorenko, MMSc, and Megan Fairweather, BS, in preparing this manuscript.
Author Affiliations: From the Health Services Research & Development Center of Excellence (SBZ), VA Puget Sound Health Care System, Seattle, WA; Public Health Sciences Division (SBZ, CMM, SDR), Fred Hutchinson Cancer Research Center, Seattle, WA; School of Pharmacy (DKB), University of Washington, Seattle, WA; Department of Urology (DFP), University of Southern California, Los Angeles, CA; Division of Cancer Prevention and Control (IJH, JLS, DUE), Centers for Disease Control and Prevention, Atlanta, GA; Department of Urology (IMT), University of Texas Health Science Center, San Antonio, TX; and Division of Urology Services (TEK), Medical University of South Carolina, Charleston, SC. Dr Penson is now with the Vanderbilt Institute for Medicine and Public Health, Vanderbilt University Medical Center, Nashville, TN.
Funding Source: This publication was supported by Cooperative Agreement 1-U48-DP-000050 from the Centers for Disease Control and Prevention, Prevention Research Centers Program, through the University of Washington Health Promotion Research Center. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
Case ascertainment for the focus group research was supported by the Cancer Surveillance System of the Fred Hutchinson Cancer Research Center, which is funded by Contract N01-PC-35142 from the Surveillance, Epidemiology and End Results (SEER) Program of the National Cancer Institute with additional support from the Fred Hutchinson Cancer Research Center and the State of Washington.
Author Disclosures: The authors (SBZ, CMM, DKB, DFP, IJH, JLS, DUE, IMT, TEK, SDR) report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.
Authorship Information: Concept and design (SBZ, CMM, DFP, IJH, JLS, DUE, TEK, SDR); acquisition of data (SBZ, DFP, IMT, TEK, SDR); analysis and interpretation of data (SBZ, DKB, DFP, IJH, DUE, SDR); drafting of the manuscript (SBZ, CMM, DKB, DFP, IJH, SDR); critical revision of the manuscript for important intellectual content (SBZ, CMM, DFP, JLS, DUE, IMT, SDR); statistical analysis (DKB); provision of study materials or patients (DFP, TEK); obtaining funding (IJH); administrative, technical, or logistic support (JLS, IMT); and supervision (DFP).
Address correspondence to: Scott D. Ramsey, MD, PhD, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, M3-B232, Seattle, WA 98109-1024. E-mail: email@example.com.
1. Ries L, Melbert D, Krapcho M, et al. SEER Cancer statistics review, 1975-2005. http://seer.cancer.gov/csr/1975_2005/. Based on November 2007 SEER data submission, posted to the SEER Web site, 2008. Accessed April 2010.
2. Wilt TJ, MacDonald R, Rutks I, Shamliyan TA, Taylor BC, Kane RL. Systematic review: comparative effectiveness and harms of treatments for clinically localized prostate cancer. Ann Intern Med. 2008;148(6):435-448.
3. Harlan LC, Potosky A, Gilliland FD, et al. Factors associated with initial therapy for clinically localized prostate cancer: prostate cancer outcomes study. J Natl Cancer Inst. 2001;93(24):1864-1871.
4. Cooperberg MR, Broering JM, Litwin MS, et al; CaPSURE Investigators. The contemporary management of prostate cancer in the United States: lessons from the cancer of the prostate strategic urologic
research endeavor (CaPSURE), a national disease registry. J Urol. 2004;171(4):1393-1401.
5. Holmboe ES, Concato J. Treatment decisions for localized prostate cancer: asking men what’s important. J Gen Intern Med. 2000;15(10):694-701.
6. Potosky AL, Davis WW, Hoffman RM, et al. Five-year outcomes after prostatectomy or radiotherapy for prostate cancer: the prostate cancer outcomes study. J Natl Cancer Inst. 2004;96(18):1358-1367.
7. Crawford ED, Bennett CL, Stone NN, et al. Comparison of perspectives on prostate cancer: analyses of survey data. Urology. 1997;50(3):366-372.
8. Zeliadt SB, Ramsey SD, Penson DF, et al. Why do men choose one treatment over another? A review of patient decision making for localized prostate cancer. Cancer. 2006;106(9):1865-1874.
9. Berry DL, Ellis WJ, Woods NF, Schwien C, Mullen KH, Yang C. Treatment decision-making by men with localized prostate cancer: the influence of personal factors. Urol Oncol. 2003;21(2):93-100.
10. Feldman-Stewart D, Brundage MD, Hayter C, et al. What questions do patients with curable prostate cancer want answered? Med Decis Making. 2000;20(1):7-19.
11. Feldman-Stewart D, Brundage MD, Nickel JC, MacKillop WJ. The information required by patients with early-stage prostate cancer in choosing their treatment. BJU Int. 2001;87(3):218-223.
12. Feldman-Stewart D, Brundage MD, Van Manen L, Skarsgard D, Siemens R. Evaluation of a question-and-answer booklet on early-stage prostate-cancer. Patient Educ Couns. 2003;49(2):115-124.
13. Germino BB. Psychosocial and educational intervention trials in prostate cancer. Semin Oncol Nurs. 2001;17(2):129-137.
14. Demark-Wahnefried W, Schildkraut JM, Iselin CE, et al. Treatment options, selection, and satisfaction among African American and white men with prostate carcinoma in North Carolina. Cancer. 1998;83(2):320-330.
15. Diefenbach MA, Dorsey J, Uzzo RG, et al. Decision-making strategies for patients with localized prostate cancer. Semin Urol Oncol. 2002;20(1):55-62.
16. Davison BJ, Gleave ME, Goldenberg SL, Degner LF, Hoffart D, Berkowitz J. Assessing information and decision preferences of men with prostate cancer and their partners. Cancer Nurs. 2002;25(1):42-49.
17. Clark JA, Bokhour BG, Inui TS, Silliman RA, Talcott JA. Measuring patients’ perceptions of the outcomes of treatment for early prostate cancer. Med Care. 2003;41(8):923-936.
18. Klabunde CN, Reeve BB, Harlan LC, Davis WW, Potosky AL. Do patients consistently report comorbid conditions over time? Results from the prostate cancer outcomes study. Med Care. 2005;43(4):391-400.
19. Potosky AL, Harlan LC, Stanford JL, et al. Prostate cancer practice patterns and quality of life: the Prostate Cancer Outcomes Study. J Natl Cancer Inst. 1999;91(20):1719-1724.
20. Roth AJ, Rosenfeld B, Kornblith AB, et al. The memorial anxiety scale for prostate cancer: validation of a new scale to measure anxiety in men with prostate cancer. Cancer. 2003;97(11):2910-2918.
21. Mehta SS, Lubeck DP, Pasta DJ, Litwin MS. Fear of cancer recurrence in patients undergoing definitive treatment for prostate cancer: results from CaPSURE. J Urol. 2003;170(5):1931-1933.
22. Rose A, Peters N, Shea JA, Armstrong K. Development and testing of the health care system distrust scale. J Gen Intern Med. 2004;19(1):57-63.
23. National Cancer Institute. What is the APECC study? Outcomes Research. 2008. http://outcomes.cancer.gov/surveys/apecc/. Accessed November 17, 2008.
24. Litwin MS, Hays RD, Fink A, et al. Quality-of-life outcomes in men treated for localized prostate cancer. JAMA. 1995;273(2):129-135.
25. Wei JT, Dunn RL, Litwin MS, Sandler HM, Sanda MG. Development and validation of the expanded prostate cancer index composite (EPIC) for comprehensive assessment of health-related quality of life in men with prostate cancer. Urology. 2000;56(6):899-905.
26. Ware J Jr, Kosinski M, Keller SD. A 12-Item Short-Form Health Survey: construction of scales and preliminary tests of reliability and validity. Med Care. 1996;34(3):220-233.
27. Ware JE, Kosinski M, Turner-Bowker DM, Gandek B. How to Score Version 2 of the SF-12® Health Survey (With a Supplement Documenting Version 1). Lincoln, RI: QualityMetric Incorporated; 2002.
28. Medical Outcomes Trust. The SF-12®: An Even Shorter Health Survey. Version 2.0. 2003. http://www.sf-36.org/tools/sf12.shtml. Accessed November 26, 2008.
29. D’Amico AV, Hui-Chen M, Renshaw AA, Sussman B, Roehl KA, Catalona WJ. Identifying men diagnosed with clinically localized prostate cancer who are at high risk for death from prostate cancer. J Urol. 2006;176(6 pt 2):S11-S15.
30. Fowler FJ Jr, McNaughton Collins M, Albertsen PC, Zietman A, Elliott DB, Barry MJ. Comparison of recommendations by urologists and radiation oncologists for treatment of clinically localized prostate cancer. JAMA. 2000;283(24):3217-3222.
31. Hall JD, Boyd JC, Lippert MC, Theodorescu D. Why patients choose prostatectomy or brachytherapy for localized prostate cancer: results of a descriptive survey. Urology. 2003;61(2):402-407.
32. Denberg TD, Beaty BL, Kim FJ, Steiner JF. Marriage and ethnicity predict treatment in localized prostate carcinoma. Cancer. 2005;103(9):1819-1825.
33. Holmes-Rovner M, Stableford S, Fagerlin A, et al. Evidence-based patient choice: a prostate cancer decision aid in plain language. BMC Med Inform Decis Mak. 2005;5:16.
34. Marceau L; New England Research Institutes. Making the Right Choice: A Decision-Aid Video for Prostate Cancer. Supported by grant R44CA62808-03 from the National Cancer Institute; McKinlay J, Principal Investigator. Watertown, MA: New England Research Institutes, Inc; 2001.
35. Gwede CK, Pow-Sang J, Seigne J, et al. Treatment decisionmaking strategies and influences in patients with localized prostate carcinoma. Cancer. 2005;104(7):1381-1390.
36. Intuitive Surgical Inc. da Vinci Prostatectomy. 2007. http://www.davinciprostatectomy.com/index.aspx. Accessed June 15, 2009.