Type of evidence
   I. Meta-analysis of multiple, well-designed controlled studies.
        A.  Studies of patients with cancer.
        B.  Studies of other clinical populations.
  II. At least one well-designed experimental study.
        A.  Studies of patients with cancer.
        B.  Studies of other clinical populations.
 III. Well-designed, quasiexperimental studies such as nonrandom-
          ized controlled, single group pre-post, cohort, time series,
          or matched case-controlled studies.
        A.  Studies of patients with cancer.
        B.  Studies of other clinical populations.
  IV. Well-designed nonexperimental studies, such as
          comparative and correlational descriptive and case studies.
        A.  Studies of patients with cancer.
        B.  Studies of other clinical populations.
   V. Case reports and clinical examples.
        A.  Studies of patients with cancer.
        B.  Studies of other clinical populations.

Strength and consistency of evidence
 A.  There is evidence of type I or consistent findings from multiple
     studies of types II, III, or IV.
 B.  There is evidence of types II, III, or IV, and findings are gen-
     erally consistent.
 C.  There is evidence of types II, III, or IV, but findings are incon-
     sistent.
 D.  There is little or no evidence, or there is type V evidence only.

Panel Consensus -- Practice recommended on the basis of opinion of experts in pain management.