Page 48 - An Evidence Review of Active Surveillance in Men With Localized Prostate Cancer

described as well as clearly reported. Only RCTs and prospective comparative studies could
receive an A grade. Retrospective studies could be graded either B or C. For all studies, we used
(as applicable): the report of eligibility criteria, the similarity of the comparative groups in terms
of baseline characteristics and prognostic factors, the report of intention-to-treat analysis,
important differential loss to followup between the comparative groups or overall high loss to
followup, and the validity and adequacy of the description of outcomes and results.

A (good). Quality A studies have the least likelihood of bias, and their results are considered
most valid. They generally possess the following: a clear description of the population, setting,
interventions, and comparison groups; appropriate measurement of outcomes; appropriate
statistical and analytic methods and reporting; no reporting errors; clear reporting of dropouts
and a dropout rate less than 20 percent; and no obvious bias. Only prospective studies may
receive a grade of A.

B (fair/moderate). Quality B studies are susceptible to some bias, but not sufficiently to
invalidate results. They do not meet all the criteria in category A due to some deficiencies, but
none likely to introduce major bias. Quality B studies may be missing information, making it
difficult to assess limitations and potential problems.

C (poor). Quality C studies have been adjudged to carry a substantial risk of bias that may
invalidate the reported findings. These studies have serious errors in design, analysis, or
reporting and contain discrepancies in reporting or have large amounts of missing information.

Systematic Reviews

Our assessment of systematic reviews was based on methodological guidelines for reviews of
10
11
studies of therapeutic interventions or epidemiological studies. We also assessed the quality
of reviews by extracting information on the items included in the Assessment of Multiple
Systematic Reviews (AMSTAR) checklist. 12,13 Because AMSTAR was developed for typical
published systematic reviews (and not evidence reports where often the use of specific methods
or reporting practices is not at the discretion of the investigators) we did not use this checklist to
assess the quality of evidence reports considered as sources of evidence for this review (i.e., the
AHRQ reviews on prostate cancer treatments).

Data Synthesis and Presentation

We summarized all included studies in narrative form as well as in summary tables (see
below) that condense the important features of the study populations, design, intervention,
outcomes, and results. For Key Questions 1-4 we synthesized the extracted information
qualitatively. Because there was extensive heterogeneity in reporting information for most
variables and substantial potential for population overlap between studies for all Key Questions
(e.g., the majority of epidemiologic studies considered eligible for Key Question 1 were based on
the SEER and CaPSURE databases and covered overlapping periods of time), we did not
perform additional quantitative analyses (meta-analyses).
When appropriate we summarized the characteristics of eligible studies using summary
14
statistics (means, medians, ranges and standard deviations). For Key Question 1, we created
line graphs depicting trends over time using publicly available information from the SEER Web
site (http://seer.cancer.gov/; last accessed September 30, 2011). For Key Question 2, we

13