Comparative Effectiveness Research for Prostate Cancer Radiation Therapy

Current Status and Future Directions

Xinglei Shen; Nicholas G Zaorsky; Mark V Mishra; Kathleen A Foley; Terry Hyslop; Sarah Hegarty; Laura T Pizzi; Adam P Dicker; Timothy N Showalter

Disclosures

Future Oncol. 2012;8(1):37-54.

Conclusion

CER uses a variety of methods to arrive at optimal treatment decisions for individual patients under usual-care conditions. Given our increasing emphasis on effectiveness rather than sole efficacy, CER will continue to be an important focus in biomedical research. PC, in particular, represents a high-impact site for CER because of its prevalence, diversity of treatment options and potentially high cost of care. Current CER work has provided evidence not available from efficacy studies for RT, but conclusions must be interpreted with caution given the limitations in current studies. Continued improvements and refinement in research tools and the development of integrated data sources will help to improve the reliability of CER studies.

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Table 1. Data sources for observational comparative effectiveness research in radiation oncology.
Source	Advantages	Disadvantages
Medical records	• Detailed information on clinical presentation and outcomes of care	• Highly technical processes of radiotherapy are not consistently documented in patient records
Medicare claims	• Technical details of radiotherapy are reported for claiming reimbursement • Can link to physician and healthcare market databases • Can sometimes link to state cancer registries	• Limited details of cancer diagnoses (i.e., stage) and outcomes other than mortality (i.e., toxicity of treatment) • Data only for patients aged ≥65 years
SEER-Medicare database	• Technical details of radiotherapy are reported by Medicare • SEER reports clinical details of cancer • Can link to physician and healthcare market databases	• Data available for only 17 regions of the USA • Limited details on outcomes other than mortality
Linked registry-insurance claims database	• Clinical and technical details of treatment available • Data for younger and older patients	• Not widely available for radiotherapy or cancer
Prospective registry	• Well suited for specific clinical questions and cohorts • Prospective design allows for use of validated assessments • Can incorporate patient-reported outcomes	• Unique technology identifiers required • Not currently available for radiotherapy
Secondary analyses of randomized trials	• Patient, tumor and treatment characteristics well documented • Morbidity assessed with validated instruments	• Small sample size • Limited external validity

Sidebar

Executive Summary

What is Comparative Effectiveness Research?

Comparative effectiveness research (CER) is defined as research aimed to guide healthcare decisions by focusing on the effectiveness, benefits and harms of one form of treatment over others.
CER can complement data from randomized clinical trials by measuring the effect of different treatment on all patient populations, including those traditionally excluded from randomized clinical trials.
With proposed changes to the USA healthcare system, there is growing interest in CER.

CER for Prostate Cancer

Patients with localized prostate cancer have a multitude of different treatment options including active surveillance, radical prostatectomy and multiple forms of radiation therapy (RT).
There is an unmet need for data directly comparing the effectiveness of these different prostate cancer treatment options.
CER focused on the determining the effectiveness of these different treatment options has been highlighted as a top priority by the Institute of Medicine.

CER for Prostate Cancer RT

Comparisons among RT modalities provide insight into comparative effectiveness of RT options.
– Although no randomized clinical trials have directly compared traditional 3D conformal RT, intensity modulated RT, brachytherapy or proton-beam therapy, all treatment modalities are in use in the USA.
– CER utilizing population-based data has been able to address important questions regarding the different RT modalities that will likely never be addressed in randomized controlled trials.
3D conformal RT versus intensity modulated RT and proton-beam therapy versus conformal RT/intensity-modulated RT.
– Based on observational CER studies, intensity-modulated RT appears to reduce late-onset gastrointestinal and genitourinary complications. The effectiveness of proton-beam therapy remains to be defined.

Future Directions for CER of Prostate Cancer RT

Developing better tools for CER in prostate cancer RT must be developed.
– Research databases for CER should be improved to permit more effective and informative observational studies that include a rich range of variables.
Novel approaches to CER in prostate cancer RT will provide valuable insights.
– Clinical trial designs may, in the future, incorporate pragmatic or adaptive approaches to improve understanding of the clinical effectiveness of prostate cancer RT.

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