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Progression-free survival

Progression-free survival (PFS) is the length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse[1]. PFS is widely used as a surrogate endpoint in oncology[2].

Time to progression does not count patients who die from other causes but is otherwise a close equivalent to PFS, unless there are many such events[3]. The FDA gives separate definitions and prefers PFS[4].

PFS is often used as a clinical endpoint in randomized controlled trials for cancer therapies[5]. PFS is a metric frequently used by the UK National Institute for Health and Clinical Excellence and the FDA to evaluate the effectiveness of a cancer treatment[6][7].

Studies find that new cancer drugs approved by the FDA improve progression-free survival by a median of 2 to 3 months, depending on the sample and the time period analysed[7]. A surrogate endpoint is a measure of effect of a specific treatment that may correlate with a real clinical endpoint but does not necessarily have a guaranteed relationship[8].

Why it matters to investors

The use of PFS for proof of effectiveness and regulatory approval is controversial[5]. PFS improvements do not always result in corresponding improvements in overall survival, and the control of the disease may come at the biological expense of side effects from the treatment itself[9].

Related: Randomized controlled trial

Sources

  1. "NCI Dictionary of Cancer Terms" . National Cancer Institute . cancer.gov (via Wikipedia: Progression-free survival)
  2. Dancey JE, Dodd LE, Ford R, et al. (2009). "Recommendations for the assessment of progression in randomised cancer treatment trials". Eur. J. Cancer . 45 (2): 281– 9. doi : 10.1016/j.ejca.2008.10.042 . PMID 19097775 . doi.org (via Wikipedia: Progression-free survival)
  3. "Progression-free survival and time to progression as primary end points in advanced breast cancer: often used, sometimes loosely defined" . Archived from the original on 2015-06-12. {{ cite journal }} : Cite journal requires | journal= ( help ) web.archive.org (via Wikipedia: Progression-free survival)
  4. "Guidance for Industry Clinical Trial Endpoints for the Approval of Cancer Drugs and Biologics" . Food and Drug Administration . 25 January 2021. fda.gov (via Wikipedia: Progression-free survival)
  5. "Progression-free survival (PFS) and time to progression (TTP) as surrogate endpoints for median overall survival (mOS) in metastatic colorectal cancer (MCRC): Analysis from 34 randomized controlled trials (RCTs) of first-line chemotherapy" . {{ cite journal }} : Cite journal requires | journal= ( help ) asco.org (via Wikipedia: Progression-free survival)
  6. BMJ 31-Jan-2009 "NICE and the challenge of cancer drugs" p271 (via Wikipedia: Progression-free survival)
  7. Fojo T, Mailankody S, Lo A (2014). "Unintended Consequences of Expensive Cancer Therapeutics—The Pursuit of Marginal Indications and a Me-Too Mentality That Stifles Innovation and Creativity: The John Conley Lecture". JAMA Otolaryngol Head Neck Surg . 140 (12): 1225– 1236. doi : 10.1001/jamaoto.2014.1570 . PMID 25068501 . doi.org (via Wikipedia: Progression-free survival)
  8. Biomarkers Definitions Working Group (March 2001). "Biomarkers and surrogate endpoints: Preferred definitions and conceptual framework". Clinical Pharmacology & Therapeutics . 69 (3): 89– 95. doi : 10.1067/mcp.2001.113989 . PMID 11240971 . S2CID 288484 . doi.org; De Gruttola, Victor G; Clax, Pamela; DeMets, David L ; Downing, Gregory J; Ellenberg, Susan S; Friedman, Lawrence; Gail, Mitchell H; Prentice, Ross; Wittes, Janet; Zeger, Scott L (October 2001). "Considerations in the Evaluation of Surrogate Endpoints in Clinical Trials". Controlled Clinical Trials . 22 (5): 485– 502. doi : 10.1016/S0197-2456(01)00153-2 . PMID 11578783 . doi.org; Cohn, J. N. (29 June 2004). "Introduction to Surrogate Markers" . Circulation . 109 (25 suppl 1): IV–20–IV-21. doi : 10.1161/01.CIR.0000133441.05780.1d . PMID 15226247 . doi.org (via Wikipedia: Clinical endpoint)
  9. Booth, Christopher M.; Eisenhauer, Elizabeth A. (2012). "Progression-Free Survival: Meaningful or Simply Measurable?" . Journal of Clinical Oncology . 30 (10): 1030– 1033. doi : 10.1200/JCO.2011.38.7571 . PMID 22370321 . doi.org (via Wikipedia: Progression-free survival)

Checked 23 October 2026. How we check sources