PSA predictive for mortality in men with the highest PSA scores

Issue: June 25, 2011

2011 ASCO Annual Meeting

Results from a 30-year study of Swedish men showed that close monitoring of men with the highest 10% of PSA scores could prevent nearly half of all prostate cancer deaths.

Risk for disease-specific death was only 0.2% and risk for metastasis was never greater than 0.5% in men with a PSA score at or below median at age 60. Most men may only need three lifetime PSA tests from between age 44 and age 60, said Hans Lilja, MD, PhD, attending research clinical chemist at Memorial Sloan-Kettering Cancer Center in New York.

“These men would not likely importantly benefit from further testing,” he told HemOnc Today. “They could be spared from further testing. For about half the population, you could eliminate further intervention on these men who have very little if anything to gain from screening. PSA measured at age 60 was strongly associated with the outcome of death from prostate cancer.”

Lilja is scheduled to present the results Monday at the 2011 ASCO Annual Meeting.

Lilja et al analyzed PSA in archived blood plasma collected from 1974 to 1992 as part of the Malmö Preventive Project, a large, representative cohort of Swedish men not subject to screening. Most men were aged 44 to 50 years and followed for up to 30 years.

Researchers performed a case control study nested within a cohort of 12,090 men who provided blood from 1974 to 1986, 4,999 men who provided a repeat sample 6 years later and an independent cohort of 1,167 men who provided blood at age 60. Men with evidence of prostate cancer metastasis or death (n=252) were matched 3:1 with controls.

At 30-years follow-up, PSA was strongly associated with risk for prostate cancer death or metastasis up to 30 years later for men 44 to 50 (AUC=0.70), 51-55 (AUC=0.76) and 60 and older (AUC=0.90). At a median follow-up of 27 years, 44% of cancer deaths in men aged 44 to 50 occurred in men with PSA >1.6 ng/mL.

The risk for death from metastatic prostate cancer progressively declined if a man’s PSA level remained below the median for the population in their age group as he aged. Researchers determined that 28% of metastases or deaths from prostate cancer occurred in men aged 44 to 50 who had a PSA below the median of 0.7 ng/mL. For men aged 51 to 55 with a PSA less than the median, 0.8 ng/mL, the risk for metastases or death was 18%. At age 60, only 5% of metastases or deaths occurred in men below the median 1.1 ng/mL.

Lilja added that studies need to be done to determine if these results will hold in men of other races, particularly men at high risk, like blacks. It is impossible to extrapolate these results to men of other races because the cohort was almost entirely white, he said. – by Jason Harris

For more information:

Lilja H. #4542. Presented at: 2011 ASCO Annual Meeting; Chicago; June 3-7, 2011.

Disclosure: Dr. Lilja reported no relevant financial disclosures.

The key thing is that a low PSA at an early age, say if the patient is younger than 50, may be very predictive. That’s powerful from a public health perspective. If a patient has a PSA under 1, his chance of getting prostate cancer appears to be very low. It’s not zero, but that’s still very reassuring for large numbers of men. Moreover, the men who develop prostate cancer later tend not to have really aggressive cancers that may take their lives. PSA testing may be becoming more like colonoscopy where, if a patient’s colonoscopy is negative, he’s protected for the next 10 years. I can foresee a day when a patient has a PSA test at 40, 50 and 60 and, so long as the results come back within a pre-specified range, the patient is probably safe. The entire cohort is Caucasian so these results may not apply to other ethnic and racial groups. Obviously there are limitations to these results, but this sets a nice, new bar.

- Nicholas J. Vogelzang, MD
Medical Director of the Developmental Therapeutics Committee,
US Oncology Research, Las Vegas

Disclosure: Dr. Vogelzang reported no relevant financial disclosures.

Otis W. Brawley, MD

The big question is still: Does prostate cancer screening save lives? This study looks at whether we can be predict if a cancer needs to be treated. This is good science, but we still have the lingering question of whether anyone who gets screened does not die because he was screened and treated. This is trying to separate a population of men who likely won't die if they are diagnosed with prostate cancer from men who have the deadly kind of prostate cancer, but these results don't tell us if screening saves lives. It gets us closer to answering that question. One of the great problems within American medicine especially, has been that, for the longest time, a number of physicians especially urologists have refused to recognize that there is a kind of prostate cancer that doesn't need to be treated and is no threat to the patient's health. This paper and other papers like it help because there are more and more people accepting that the kind of prostate cancer that is not aggressive and will never kill does exist. That helps us get a little more scientific and better define the scientific questions we need to address.

- Otis W. Brawley, MD
Chief Medical Officer, American Cancer Society

Disclosure: Dr. Brawley reported no relevant financial disclosures.

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