Detecting overall survival benefit derived from progression-free survival

November 10, 2009

Overall survival (OS) may be a reasonable primary endpoint when the median survival postprogession (SSP) is less than 6 months, but it is too high a hurdle when SPP is longer than 12 months, according to a new study published online November 9 in the Journal of the National Cancer Institute.

This study was undertaken to examine whether progression-free survival (PFS) or OS is the most appropriate endpoint in clinical trials of metastatic cancer, and to determine if it is reasonable to expect that treatment benefit in PFS carries over to OS.

To address these questions, Donald A. Berry, Ph.D., of the Department of Biostatistics, University of Texas M. D. Anderson Cancer Center in Houston, and colleagues simulated clinical trials with two arms having respective medians for PFS of 6 and 9 months. Researchers partitioned OS into two parts and expressed it as the sum of PFS and SPP. Probabilities of a benefit in OS were determined for various median SPP, by assuming no treatment-related difference in SPP, and for different P values for PFS.

They found that, at a P value for improved PFS of .001, there was a greater than 90% probability for statistical significance in OS if the median SPP was 2 months. However, the probability for statistical significance was less than 20% if the median SPP was 24 months.

"For clinical trials with a PFS benefit, a lack of statistical significance in OS does not imply a lack of improvement in OS," the authors write. "For diseases with long SPP, the variability in SPP so dilutes the comparison that statistical significance is likely lost. Thus, OS is a reasonable primary endpoint when median SPP is short…but is too high a hurdle when SPP is long…As the clinician's armamentarium of salvage therapies grows and becomes more varied, SPP will get longer. When SPP gets sufficiently long oncology researchers and regulators will have to drop OS as the primary endpoint in clinical trials."

Source: (news : web)

Explore further: Mars Express PFS spectrometer back at work

Related Stories

Mars Express PFS spectrometer back at work

November 2, 2005

The Planetary Fourier Spectrometer (PFS) on board ESA’s Mars Express spacecraft is now back in operation after a malfunction, reported a few months ago. The instrument had been successfully investigating the chemical composition ...

Prostate cancer vaccines more effective with hormone therapy

July 10, 2008

Among patients with castration-resistant prostate cancer, the addition of hormone therapy following vaccine treatment improved overall survival compared with either treatment alone or when the vaccine followed hormone treatment, ...

Keyboards and mice can harbor hospital infections

September 30, 2009

Although hospital computer equipment can act as a reservoir for pathogenic organisms, including MRSA, researchers writing in the open access journal BMC Infectious Diseases found that bacterial contamination rates from computer ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

(PhysOrg.com) -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.