Colorectal Ca

30 COMMUNITY ONCOLOGY ■ January/February 2005 www.CommunityOncology.net

Gaps in colorectal cancer outcomes research Xin Ye, MS,1 Samuel Wagner, PhD,1,2 Jon C. Schommer, PhD,1 Jose William Castellanos, MD,1 and Luz Dalia Sanchez, MD1

1 University of Minnesota, Minneapolis, MN, and 2 Pfizer Inc, New York, NY

This study was designed to examine the current status of—and identify potential gaps in—colorectal cancer outcomes research. English-language articles published from 1999 to 2003 were retrieved from MEDLINE using the search term "colorectal neoplasms OR colorectal cancer" and specific MeSH terms dealing with the effectiveness of interventions on final outcomes and factors, such as costs, involved in those interventions. Articles excluded were biological or pathological studies; studies in non-human subjects; clinical trials or reviews mainly answering efficacy-related questions; and letters, comments, and editorials. Abstracts were reviewed and classified by study design, endpoints, and impact. Full-text articles were retrieved as needed for classification. Of the 2,270 articles retrieved, 525 met the inclusion criteria for the analysis. Most were retrospective cohort studies (216 articles, 41.1%). The most common endpoints were survival (371 articles, 70.7%), followed by quality of life (102 articles, 19.4%), economic cost (81 articles, 15.4%), and patient satisfaction (17 articles, 3.2%). In terms of their impact, 481 articles (91.6%) were classified as level 1 (adds to the knowledge base only); 26 (5.0%); as level 2 (affects practice policies); 16 (3.0%), as level 3 (influences healthcare delivery); and 2 (0.4%), as level 4 (leads to changes in health outcomes). In conclusion, most colorectal cancer outcomes studies published in the past 5 years focused on survival, and the majority represented impact level 1 research. Patient satisfaction was almost ignored. Based on these findings, colorectal cancer outcomes research that answers more than survival questions and represents higher impact levels is warranted.

Original Research

Manuscript received October 16, 2004; accepted December 8, 2004.

This study was presented in part at the 9th Annual International Meeting of the International Society for Pharmacoeconomics and Outcomes Research (ISPOR), held May 16–19, 2004, in Arlington, VA.

Correspondence to: Samuel Wagner, PhD, 5775 Green Valley Circle, Aubrey, TX 76227; e-mail: [email protected]

Commun Oncol 2005;2:30–35 © 2005 Elsevier Inc. All rights reserved.

C olorectal cancer has been a pub-lic health and socioeconomic concern for decades, accounting for 10%–15% of all cancers, and is the second leading cause of cancer deaths in Western coun-

tries. During 1996–2000, the annual incidence of colorectal cancer in the United States was as high 54.2 per 100,000 population, and more than 50,000 people died of colorectal cancer every year.1

In recent years, with a broadening array of ther-apeutic options available and varying medical costs associated with these options, there has been an increase in interest in outcomes research in cancer patients. Outcomes research has become essential in providing useful information in colorectal can-cer treatment for decision makers, including pro-viders, patients, and payers. Few studies, however, have systematically evaluated colorectal cancer out-comes research in terms of key final endpoints and levels of impact.

To help understand the effects of outcomes re-search on practice, policy, and actual health out-comes, the Agency for Healthcare Research and Quality (AHRQ) developed a framework through

which basic findings in outcomes research can be linked over time to the health of patients.2 In this framework, outcomes research is classified by its impact level,2 as follows:

Level 1: Studies that add to the knowledge base only and do not represent a direct change in poli-cy or practice. An example given by AHRQ was a study that examined the prevalence and costs of ad-verse drug events.2, 3

Level 2: Studies that may lead to a policy or program change as a direct result of the research. An example given by AHRQ was a study that in-vestigated otitis media-related antibiotic prescrib-ing patterns, outcomes, and expenditures in a pedi-atric Medicaid population.2, 4

Level 3: Studies that may cause a potential

January/February 2005 ■ COMMUNITY ONCOLOGY 31 Volume 2/Number 1

change in what clinicians or patients do or results in a change in a care pat-tern. An example given by AHRQ was a study that developed the VF-14 measure to assess indications for and outcomes after cataract surgery.2, 5

Level 4: Studies that may change actual health outcomes (clinical, eco-nomic, quality of life, and/or patient satisfaction). An example given by AHRQ was a study that concluded that data feedback, training in contin-uous quality improvement, and visits to other medical centers improved coronary artery bypass graft surgery mortality by 24%.2,6

Although the process from scien-tific knowledge development to its practical application will rarely be as systematic and orderly as described by this framework, it provides use-ful guidance on how to assess out-comes research. For instance, Tunis and Stryer concluded that the major-ity of outcomes research sponsored by AHRQ from 1989 to 1997 and cat-egorized using this framework had made substantial contributions at lev-el 1 but had had little impact at high-er levels.2, 7

The primary objective of this study was to describe reported research re-garding colorectal cancer outcomes in terms of study design, targeted im-pact level, and final endpoints (sur-vival, quality-of-life outcomes, cost, and patient satisfaction) and to iden-tify potential gaps in colorectal cancer outcomes research. This was accom-plished by performing an extensive and systematic literature review of the MEDLINE database, using the AHRQ framework to characterize the impact of each article retrieved.

Methods

Definition of cancer outcomes research

Despite the common use of the term “outcomes research,” there is no consensus on its precise definition. In the past, outcomes research has often been recognized more by what it is

not (eg, evaluation of survival or dis-ease response in clinical trials) than by what it is.8 As a result, a single defin-ing theme never developed. For their review of outcomes research in oncol-ogy, Lee et al8 adopted the definition of “health services research” from the Association of Health Services Re-search: “a field of inquiry using quan-titative or qualitative methodology to examine the impact of the organiza-tion, financing, and management of health care services on the access to, delivery, cost, outcomes and quality of services.” From the perspective of the National Cancer Institute, Lipscomb and Snyder7 argued that emphasis should be placed on final endpoints, such as survival, health-related quali-ty of life, patient satisfaction, and eco-nomic burden.

In light of the previous literature, we propose that cancer outcomes re-search should be intervention-cen-tered, focusing on final endpoints but also covering a broad range of issues—such as quality of care, access, and de-cision-making—that are related to the interventions. Thus, for the purposes of this paper and building on previous definitions, we define cancer outcomes research as “a field of inquiry that ex-amines and evaluates the effectiveness of interventions on cancer final end-points (including survival, quality of life, patient satisfaction, and economic burden) and factors related to the or-ganization, financing, and manage-ment of such interventions.”

Search paradigm

Guided by our definition of can-cer outcomes research, we performed a comprehensive search of the MED-LINE database to retrieve articles published from January 1999 through November 2003 that were related to outcomes research in colorectal can-cer. First, Medical Subject Heading (MeSH) terms covering any final end-points were identified. These terms in-cluded economics, cost and cost anal-ysis, survival, quality of life, personal

satisfaction/satisfaction, and mental health. Second, MeSH terms covering any component of general outcomes research were identified. These terms included: outcome assessment (health-care), health service accessibility, health service research, quality of health care, quality assurance (healthcare), quality indicators (healthcare), practice guide-line, and decision making. Finally, ar-ticles that matched both MeSH terms related to final endpoints and MeSH terms related to general outcomes re-search were retrieved.

Exclusion criteria

The literature search was limited to articles written in English involv-ing human subjects. Articles excluded from this review were (1) studies deal-ing primarily with the biology or pa-thology of cancer; (2) studies without any intervention involved; (3) studies focusing mainly on intermediate end-points, including tumor size or treat-ment response; and (4) letters, com-ments, and editorials. In addition, as the key feature distinguishing clinical research from outcomes research was the emphasis on efficacy (the effect of an intervention measured under con-trolled circumstances, as in a clinical trial), rather than on effectiveness (the effect of an intervention as applied to a broad population in real practice).Clinical trials and clinical reviews with only survival endpoints, as opposed to quality-of-life studies or cost analyses, were also excluded.8

Classification

The abstracts were classified ac-cording to study designs, final end-points, and impact levels. The clas-sifications and operational definitions for each category are given in the sidebar “Definitions of study designs and final endpoints”; impact levels are defined in the introduction to this paper. We developed rules for cod-ing each article into its corresponding classification for study designs, final endpoints, and impact levels.

Gaps in colorectal cancer outcomes research ORIGINAL RESEARCH


In addition, we trained two re-searchers to conduct coding for a rel-atively small number of articles (n = 30) to assess interjudge reliability. The researchers were trained on the rules and procedures for coding, and they independently scored each article. In-terjudge reliabilities were then calcu-lated by using the Perrault and Leigh reliability index (I),9 as follows:

I = {[(F/N) – (1/k)] [k/(k – 1)]}1/2

where F = the observed frequency of agreement between judges, N = the total number of judgments, and k = the number of categories.

The two judges had a high level of agreement in their scoring (inter-judge reliability scores were greater than 0.95 for study design, final end-point, and impact level; respectively). In light of reliability scores well above the recommended level of 0.90, one researcher completed the rest of the coding for this study.

Study designs were classified as clinical trials, retrospective observa-tional studies, prospective observa-tional studies, decision analyses, re-view studies and meta-analyses, and others. We classified final endpoints as survival, quality of life, satisfaction, cost, and utilization pattern (stud-ies investigating factors related to the organization, financing, and manage-ment of cancer interventions).

A paper was assigned one of four AHRQ impact levels (see introduc-tion) based on the study’s targeted impact, which was judged from the study objective and conclusion stat-ed in the abstract. If the authors only presented their findings without a recommendation for policy or prac-tice change, then the study was clas-sified as level 1. Such studies include new tools and methods for research, instruments and techniques to as-sist clinical decision-making, studies that identify areas in which scientif-ic knowledge is needed, and studies that stimulate rethinking and ques-tioning within a clinical specialty.2

For example, Ramsey et al10 found that the lifetime medical costs for long-term colorectal survivors were up to $19,516 higher than control costs and were highest for young-er age groups and those with early-stage disease. However, no policy and practice change was suggested in the paper, and it was thus classified as level 1.

If the authors of the paper intend-ed to recommend to decision-makers a potential change in health policy or programs based on the result(s) of the research described (eg, “the results suggest” or “recommend”), then the study was classified as level 2, and its focus was considered to be on a rela-tively macro level. For instance, Fish-er et al’s paper11 was classified as level 2 because the study found that Medi-care enrollees with colorectal cancer in higher spending regions received more care than those in lower spend-ing regions but did not have better health outcomes or satisfaction with care, and the authors suggested poli-cies to better manage further spend-ing growth.

If the authors intended to recom-mend to clinicians a potential change in practice based on the article’s find-ings, then the study was classified as level 3. An example was Heslin et al’s study,12 which concluded that aggres-sive surgical management of patients with hepatic colorectal metastases is safe and may prolong overall surviv-al—and therefore should be consid-ered in all patients with metastases confined to the liver.

If the study met the requirement of levels 1, 2, and 3 and, moreover, showed actual improvement in health outcomes as a result of a specific in-tervention, then it was classifed as level 4. For example, Delaney et al13 demonstrated that for patients who undergo rectal resection with total mesorectal excision for stage T3 low rectal cancers, the overall 5-year sur-vival was increased from 52% in pa-tients not receiving preoperative ra-

diotherapy (PRT) to 63% in those receiving PRT, and the publication was classified as level 4. If multiple fi-nal endpoints were involved and each endpoint represented different levels, the level of the paper was determined by the primary endpoint and its ma-jor conclusion.

ResultsA total of 2,270 articles from 1999

through 2003 were originally retrieved by searching the MEDLINE data-base, and 525 met the inclusion crite-ria for the study. For 47 of these arti-cles, either the endpoints or the study design could not be determined from the abstract alone, and the original ar-ticles were retrieved for clarification. For the other 478 articles, the abstracts provided sufficient information for coding purposes. (A list of the studies can be obtained by contacting the cor-responding author of this article.)

Among the 1,745 articles initial-ly retrieved during the MEDLINE search but later excluded from the analysis, 600 articles were deemed to be mainly biological, pathological, or clinicopathological studies; 218 were studies that mainly focused on inter-mediate endpoints; 168 were clini-cal trials or clinical reviews with only survival endpoints; 214 were letters, comments, or editorials; 259 were studies that did not have any inter-vention; and 286 articles fit more than one exclusion criterion.

Among the 525 papers includ-ed in the analysis, a plurality of stud-ies used a retrospective observational cohort design (216 articles, 41.1%). With multiple endpoints in some studies, the most common endpoints were survival (371 articles, 70.7%), fol-lowed by quality of life (102 articles, 19.4%), economic cost (81 articles, 15.4%), utilization pattern (64 articles, 12.2%), and patient satisfaction (17 ar-ticles, 3.2%). In terms of their impact, we classified 481 articles (91.6%) as level 1, 26 (5.0%) as level 2, 16 (3.0%) as level 3, and 2 (0.4%) as level 4. The

ORIGINAL RESEARCH Ye et al


distribution of study designs, final endpoints, and impact levels among the 525 papers analyzed is provided in Table 1. The temporal trend in num-ber of colorectal cancer outcomes re-search studies published in the past 5 years is shown in Figure 1.

There was a significant difference in the proportion of papers with high-er impact levels (levels 2–4) across dif-ferent study designs (χ2 = 12.10, df = 5, P = 0.03), as well as across different research topics/endpoints (χ2 = 13.00, df = 5, P = 0.023). Among different study designs, meta-analysis/review studies had the highest percentage of higher impact levels (20.6%), fol-lowed by clinical trials (12.7%) and decision-analysis studies (12.0%). Among different research topics/end-points, studies with multiple end-points had the highest percentage of higher impact levels (17.9%).

DiscussionThe field of outcomes research in

major diseases, including colorectal cancer, has progressed over the past decades. A recent review study has examined patient-centered outcomes

research related to colorectal cancer screening and treatment and outlined the work that has been done in sever-al areas, including patient preferences, quality of life, and economic analy-sis.14 To our best knowledge, however, colorectal cancer outcomes research has not been systematically reviewed in terms of key final endpoints and tar-geted impact level. The results of our study revealed some important gaps in colorectal cancer research that was re-ported from 1999 through 2003.

Even though cancer therapy ob-jectives have changed from solely in-creasing survival to that of also im-proving patients’ quality of life and restricting total medical costs, our results showed that colorectal can-cer outcomes research still was domi-nated by survival as the primary end-point. In most cases, it was the only endpoint studied.

Some reasons might explain this phenomenon. On the one hand, most studies were a retrospective examina-tion of patients’ medical charts, and survival was the only available infor-mation in most cases. The capability of health outcomes research to rigor-ously evaluate healthcare services by measuring their clinical, economic, and humanistic outcomes was sig-nificantly limited, since most of the retrospective data, including medical charts and administrative databases, were not designed for the purpose of outcomes research. This shortcoming emphasizes the need for clinicians and outcomes researchers to work to-gether and collect more information regarding patients’ quality of life and satisfaction with their treatment, their providers, and the healthcare system.

On the other hand, no “gold stan-dard” measures for quality of life have been developed in this disease area. Several quality-of-life measures, in-cluding generic and disease-specif-

TABLE 1

Distribution of study designs, endpoints, and impact levels Level 1 Level 2 Level 3 Level 4 Level 1 (%)

Study designs

Clinical trials 55 4 3 1 87.3%

Observational-retrospective 203 6 7 0 94.0%

Observational-prospective 86 3 3 1 92.5%

Decisional analysis 44 5 1 0 88.0%

Review/meta-analysis 27 5 2 0 79.4%

Others 66 3 0 0 95.7%

Total 481 26 16 2 91.6%

Research topics/endpoints

Survival only 275 10 10 1 92.9%

Quality of life only 57 2 0 1 95.0%

Cost only 33 3 0 0 91.7%

Satisfaction only 10 1 0 0 90.9%

Pattern only 37 1 0 0 97.4%

Multiple endpoints 69 9 6 0 82.1%

Total 481 26 16 2 91.6%

FIGURE 1 Trend in number of colorectal cancer outcomes publications, 1999–2003.

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ic scales, have been utilized in the field of colorectal cancer outcomes research. However, the lack of con-sistency of quality-of-life measures across different studies has made it difficult to conduct direct compari-sons and has potentially limited the application of research findings. The most widely used measure was the European Organization for Research and Treatment of Cancer Colorectal cancer-specific quality-of-life ques-tionnaire [EORTC QLQ-CR38], which was consistent with the trend toward increased use of such scale. This might represent the beginning of a move toward standardization.14

Patient satisfaction as an endpoint was almost ignored and hardly in-vestigated. Only a few studies have looked at patients’ satisfaction with interventions such as screening, treat-ment planning, and hospital follow-up.15–17 Most of the satisfaction stud-ies showed that patients generally had a positive experience with the health-care they were receiving. They also revealed that a high level of satisfac-tion with a certain intervention led to the referral of patients who would not have otherwise considered such a procedure.18 These studies have facili-tated the understanding of colorectal cancer patients’ satisfaction with care, but the factors associated with high satisfaction and patients’ satisfaction with healthcare policy remain unclear. More research is needed to examine patients’ satisfaction and eventually improve the quality of care.

Impact of most outcomes studies minimal

The results also showed that most colorectal cancer outcomes research published from 1999 to 2003 (91.6%) added to the knowledge base about this disease only (level 1) and had no targeted higher level impact. Al-though a few studies were observed in the literature during this period that had a potential level 2 or 3 impact, only two studies had a potential level

4 impact. Those studies at level 2 or higher have covered all the final end-points/research topics, although “sur-vival” is still the most commonly seen endpoint. One level 4 study showed, through a randomized clinical trial, improved psychological health and quality of life associated with the use of progressive muscle-relaxation training in colorectal cancer patients after stoma surgery.19 The other lev-el 4 study demonstrated, through a long-term prospective cohort study, improved survival of patients who had received preoperative radiotherapy.13

The number of publications in colorectal cancer outcomes research increased gradually from 1999 through 2003; however, the propor-tion of these studies that targeted higher level impact goals remained small. Although the real impact lev-el of a particular study is difficult to assess, more colorectal cancer out-comes research should target high-er impact levels rather than adding knowledge only.

Study limitations

A number of limitations to our study should be mentioned.

First, “targeted level of impact” was used to evaluate outcomes research. However, the process of healthcare decisions, and the healthcare sys-tem itself, is extremely complex. Any change in that system will be made through the interplay of informa-tion, values, and the decision-making structure and will be the consequence of multiple interrelated factors. Thus, even when targeted level 2 or higher impacts were assumed in our study, it is uncertain whether and when any real impact would take place. Further, even if real impacts are observed, it is rarely possible to link these changes in healthcare practices or outcomes completely to the findings of any par-ticular published study.2

Second, the performed literature searches relied on MeSH terms. Using MeSH terms rather than simple key-

word searching provides a greater lev-el of access to article content beyond the terms used in titles and abstracts.20 However, MEDLINE indexing ap-pears to vary by clinical setting and journal subject, with somewhat weak-er results for pharmacoeconomics and managed-care journals than for dis-ease-specific or general medical jour-nals.21,22 Therefore, some colorectal cancer outcomes research might not have been captured by our searches.

Finally, it is difficult to determine the value of generated knowledge. The attempt to systematically re-view the potential value of outcomes research in colorectal cancer has few clear precedents. This review relied heavily on the way that the original authors presented their findings in the scientific community, and the re-sults of this study necessarily reflect the limited perspective of the review-ers themselves.

Acknowledgments: Funding for this study was provided through Pharm-acia Corporation’s sponsorship of a Managed Care Pharmaceutical Out-comes Research Fellowship at the University of Minnesota.

References

1. Weir HK, Thun MJ, Hankey BF, et al. Annual report to the nation on the status of cancer, 1975–2000, featuring the uses of sur-veillance data for cancer prevention and con-trol. J Natl Cancer Inst 2003;95:1276–1299.

2. Tunis S, Stryer D. The outcome of out-comes research at AHCPR. Publication No. AHCPR 99-R044, 1999.

3. Bates DW, Cullen DJ, Laird N, et al. In-cidence of adverse drug events and potential adverse drug events: implications for preven-tion. ADE Prevention Study Group. JAMA 1995; 274:29–34.

4. Berman S, Byrns PJ, Bondy J, Smith PJ, Lezotte D. Otitis media-related antibiotic pre-scribing patterns, outcomes, and expenditures in a pediatric Medicaid population. Pediatrics 1997;100:585–592.

5. Steinberg EP, Tielsch JM, Schein OD, et al. The VF-14: an index of functional impair-ment in patients with cataract. Arch Ophthal-mol 1994;112:630–638.

6. O’Connor GT, Plume SK, Olmstead EM, et al. A regional intervention to improve the hospital mortality associated with coronary artery bypass graft surgery. The Northern New England Cardiovascular Disease Study Group.

ORIGINAL RESEARCH Ye et al


JAMA 1996;20:841–846.7. Lipscomb J, Snyder CF. The outcomes

of cancer outcomes research: focusing on the NCI’s Quality-of-Care Initiative. Med Care 2002;40(6 suppl):III3–10.

8. Lee SJ, Earle CC, Weeks JC. Out-comes research in oncology: history, conceptual framework, and trends in the literature. J Natl Cancer Inst 2000;92:195–204.

9. Perrault WD, Leigh LE. Reliability of nominal data based on qualitative judgments. J Marketing Res 1989;26:135–148.

10. Ramsey SD, Berry K, Etzioni R. Life-time cancer-attributable cost of care for long term survivors of colorectal cancer. Am J Gas-troenterol 2002;97:440–445.

11. Fisher ES, Wennberg DE, Stukel TA, Gottlieb DJ, Lucas FL, Pinder EL. The impli-cations of regional variations in Medicare spend-ing. Part 2: health outcomes and satisfaction with care. Ann Intern Med 2003;138:288–298.

12. Heslin MJ, Medina-Franco H, Park-er M, Vickers SM, Aldrete J, Urist MM. Colorectal hepatic metastases: resection, local ablation, and hepatic artery infusion pump are associated with prolonged survival. Arch Surg 2001;136:318–323.

13. Delaney CP, Lavery IC, Brenner A, et al. Preoperative radiotherapy improves survival

for patients undergoing total mesorectal exci-sion for stage T3 low rectal cancers. Ann Surg 2002;236:203–207.

14. Provenzale D, Gray RN. Colorectal cancer screening and treatment: review of out-comes research. J Natl Cancer Inst Monogr 2004;33:45–55.

15. Schoenfeld PS, Cash B, Kita J, Pior-kowski M, Cruess D, Ransohoff D. Effective-ness and patient satisfaction with screening flexible sigmoidoscopy performed by registered nurses. Gastrointest Endosc 1999;49:158–162.

16. Papagrigoriadis S, Heyman B. Patients’ views on follow up of colorectal cancer: impli-cations for risk communication and decision making. Postgrad Med J 2003;79:403–407.

17. Walker MS, Ristvedt SL, Haughey BH. Patient care in multidisciplinary cancer clinics: does attention to psychosocial needs predict patient satisfaction? Psychooncology 2003;12:291–300.

18. Robb B, Pritts T, Gang G, et al. Quality of life in patients undergoing ileal pouch-anal anastomosis at the University of Cincinnati. Am J Surg 2002;183:353–360.

19. Cheung YL, Molassiotis A, Chang AM. The effect of progressive muscle relax-ation training on anxiety and quality of life af-ter stoma surgery in colorectal cancer patients.

Study designsClinical trials: Studies that em-

ployed either randomized controlled trials or non-randomized trials are classified as clinical trials. A random-ized trial is defined as a prospective study with an intervention group (arm) and a control group (arm), such that whether an individual is assigned to the intervention or the control group is determined by a chance pro-cess called randomization. Non-ran-domized trials are defined as studies in which interventions are planned and not observational; no random-ization process is involved.

Retrospective observational studies: Observational studies in which sub-jects’ exposure status and follow-up are determined using historical data to investigate the relationship be-tween exposure and outcome.

Prospective observational studies: Observational studies in which sub-jects’ exposure status is determined

ABOUT THE AUTHORSXin Ye, MS, is a doctoral candidate, Jon C. Schommer, PhD, is Associate Professor, Jose William Castellanos, MD, is a doctoral can-didate, and Luz Dalia Sanchez, MD, is a doctoral candidate, University of Minnesota, Graduate Program in Social and Administra-tive Pharmacy, Minneapolis, MN. Samuel Wagner, PhD, is Adjunct Professor at the University of Minnesota, Graduate Program in Social and Administrative Pharmacy, Min-neapolis, MN, and Director, Outcomes Re-search, Pfizer Inc, New York, NY.

Psychooncology 2003;12:254–266.20. Gault LV, Shultz M, Davies KJ. Vari-

ations in Medical Subject Headings (MeSH) mapping: from the natural language of patron terms to the controlled vocabulary of mapped lists. J Med Libr Assoc 2002;90:173–180.

21. Frame DSK. Use of iterative search strat-egies to increase PubMed yield for pharmacoeco-nomics research. ISPOR Connect 2003;9:4–5.

22. Haynes RB, Wilczynski N, McKibbon KA, Walker CJ, Sinclair JC. Developing op-timal search strategies for detecting clinically sound studies in MEDLINE. J Am Med In-form Assoc 1994;1:447–458.

Definitions of study designs and final endpoints at the beginning of the study and then subjects are followed through time to investigate if one or more outcomes occur.

Decisional analyses: Studies that provide quantitative support for healthcare decision-makers to man-age resources, including cost-effec-tiveness analyses, cost-benefit anal-yses, cost-utility analyses, Markov modeling, and Monte Carlo simula-tions in clinical decision-making.

Review studies: Studies that attempt to provide definitive conclusions about certain interventions through review-ing existing literature, including meta-analysis.

Others: Studies that do not fit the preceding definitions, including cross-sectional, case-control, and mixed study designs.

Final endpointsSurvival: Studies that only involve

the final endpoints primarily related to

overall, disease-specific, disease-free, or quality-of-life adjusted survival.

Quality of life: Studies that only involve the final endpoints primar-ily related to general quality-of-life measures assessed by generic qual-ity-of-life test instruments (eg, the SF-36) or disease-specific quality-of-life measures assessed by disease-specific quality-of-life instruments (eg, the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30).

Satisfaction: Studies that only involve the final endpoints related to patients’ attitude toward received care or the healthcare system.

Cost: Studies that only involve the final endpoints related to mone-tary costs from the patients’, payers’, or societal perspective.

Pattern: Studies that only investi-gate factors related to the organiza-tion, financing, and management of cancer interventions.

Multiple: Studies that cover more than one endpoint or topic.


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