Study Characteristic	Inclusion Criteria	Exclusion Criteria
Population	Adult patients with cancer	Children (defined as individuals less than 18 years old)
Intervention	Ketamine administration via oral, IV, IM, subcutaneous, intrathecal, or topical routes
Comparison	Patients with cancer who did not receive ketamine
Outcome	Pain	Any outcomes not listed
Study design	Randomized trials Nonrandomized trials Controlled before-after studies Cross-sectional Qualitative studies Interrupted time-series studies or repeated measures studies Prospective and retrospective observational studies (i.e., cohort studies and case control studies)	Descriptive studies with no outcome data Case reports and case studies Modeling studies that used simulated data Not a clinical study (e.g., editorial, nonsystematic review, and letter to the editor) Measurement or validation studies Self-described pilot studies without adequate power to assess the impact of interventions on outcomes.
Time/location	No limitation
Publication types	Full publication in a peer-reviewed journal Dissertations	Meeting abstracts, protocols without results, and gray literature