What is evidence-based oncology?

Evidence-Based Oncology: Core Definition and Framework

Evidence-based oncology is the systematic integration of the best available research evidence with clinical expertise and individual patient values to guide cancer treatment decisions, requiring explicit and judicious use of current evidence rather than relying solely on tradition or clinical intuition. 1, 2

Fundamental Components

Evidence-based medicine in oncology encompasses three essential elements that must work together: 3

• Best available external clinical evidence from systematic research, including patient-centered clinical research on diagnostic test accuracy, prognostic markers, and the efficacy and safety of therapeutic regimens 3
• Individual clinical expertise - the proficiency and judgment clinicians acquire through experience, reflected in effective diagnosis and thoughtful identification of individual patients' predicaments, rights, and preferences 3
• Patient values and preferences - incorporating what matters most to each patient in the decision-making process 2, 3

The Evidence Hierarchy in Cancer Care

The strength of evidence in oncology follows a structured hierarchy: 1

• Highest level: Meta-analyses and high-powered randomized controlled trials provide the strongest evidence for treatment effects 1
• Intermediate level: Lower-quality randomized trials, quasi-experimental studies, and well-designed observational studies 1
• Lowest level: Clinical experience and expert opinion 1

However, a critical reality exists: only 24% of recommendations in hematologic malignancy guidelines are backed by randomized clinical trials, with 21% based on lower-level evidence and 55% on clinical experience alone. 1 This gap necessitates reliance on expert consensus when high-quality data are absent. 2

The Evidence-Based Process in Oncology Practice

The practice of evidence-based oncology follows a systematic five-step approach: 3

1. Convert clinical needs into answerable questions when caring for patients creates information needs about diagnosis, prognosis, or therapy 3
2. Track down the best evidence with maximum efficiency from clinical examination, diagnostic laboratories, or research sources 3
3. Critically appraise evidence for validity (closeness to truth) and usefulness (clinical applicability) 3
4. Integrate the appraisal with clinical expertise and apply it in practice 3
5. Evaluate performance to ensure continuous improvement 3

Critical Distinctions: Efficacy vs. Effectiveness

Evidence-based oncology requires understanding the difference between efficacy and effectiveness: 4

• Efficacy refers to whether a treatment works under ideal, controlled conditions (typically in clinical trials) 4
• Effectiveness refers to whether a treatment works in real-world clinical practice with diverse patient populations 4

This distinction is particularly important because RCTs provide average treatment effects for groups but may not apply to real-world scenarios where patients have different characteristics than trial participants. 5

Integration with Clinical Guidelines

Evidence-based oncology forms the foundation for clinical practice guideline development: 1

• Guidelines translate current best evidence and expert opinion into recommendations for multidisciplinary teams 1
• The WHO acknowledges that when high-quality evidence is absent, recommendations must incorporate values, feasibility, resource considerations, and expert knowledge 2
• Guidelines should be developed through explicit consensus processes with multidisciplinary representation to minimize bias 1

Common Pitfalls and Limitations

Several important caveats exist in evidence-based oncology: 2

• Misunderstanding EBM as direct application of evidence alone overlooks the need for thoughtful identification of individual patient predicaments, rights, and preferences 2
• Lack of training in evidence-based medicine and limited scientific literacy can hinder the evidence-based process 2
• Geographic disparities exist because evidence is mainly produced in developed countries where health concerns differ from developing regions 2
• Conflict of interest between clinicians and industry remains a concern for guideline development, requiring robust policies beyond simple disclosure 2

Application in Modern Oncology

Evidence-based oncology has become ubiquitous in cancer care: 6

• Used in clinics and hospital units for symptom management decisions 6
• Incorporated into survivorship guideline development 6
• Applied through journal clubs and mobile device applications to find best interventions 6
• Integrated into committee work for developing guidelines based on best evidence and expert opinion 6