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Updated: Jun 23, 2026
09:19
Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo
Published on: February 6, 2015
Issues in using progression-free survival when evaluating oncology products
Thomas R Fleming1, Mark D Rothmann, Hong Laura Lu
1Department of Biostatistics, University of Washington, Box 357232, Seattle, WA 98195-7232, USA. tfleming@u.washington.edu
Summary
Progression-free survival (PFS) in cancer trials offers insights into tumor burden but requires careful interpretation. Magnitude of effect, not just statistical significance, is crucial for determining clinical benefit and guiding treatment decisions.
Area of Science:
- Oncology
- Clinical Trials
- Biostatistics
Background:
- Progression-free survival (PFS) is a common endpoint in oncology trials.
- PFS measures time to disease progression or death.
- Controversies exist regarding the interpretation of PFS as a sole indicator of clinical benefit.
Purpose of the Study:
- To discuss the challenges and controversies surrounding the use of PFS in oncology trials.
- To emphasize the importance of effect magnitude alongside statistical significance for PFS.
- To highlight the properties of PFS and its role in assessing anticancer agent efficacy.
Main Methods:
- Review of the definition and interpretation of PFS in clinical oncology research.
- Discussion of statistical considerations and clinical relevance of PFS.
- Analysis of the properties of PFS as an endpoint, including its sensitivity to treatment mechanisms and incorporation of death events.
Main Results:
- PFS provides insights into the effect of interventions on tumor burden.
- Statistical significance of PFS alone is insufficient to establish clinical benefit.
- The magnitude of PFS effect is critical for reliable efficacy evidence.
Conclusions:
- PFS is a valuable endpoint sensitive to cytostatic/cytotoxic effects and includes mortality.
- Interpreting PFS requires consideration of effect size and statistical strength.
- Randomized trials should ensure complete follow-up for PFS and survival, avoiding early crossover to maintain data integrity.
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