Researchers from the United Kingdom have reported that between 1994 and 2004 there has been a greater decline in prostate cancer deaths in the United States than in the United Kingdom. These authors speculated that this may be due to differences in PSA screening. The details of this study appeared in an early online publication in Lancet Oncology on April 17, 2008.¹ 

Prostate cancer is the second leading cause of cancer death in the United States. Prostate specific antigen (PSA) testing is becoming routine in men after the ages of 50-55. The PSA test was first approved by the Food and Drug Administration in 1986 as a way to monitor prostate cancer progression, but since 1988 it has also been used as a screening test, despite the fact that there is no clear evidence that such screening improves survival. Randomized controlled trials to address the issue of efficacy of screening are ongoing, but the results of these trials are several years away. While awaiting the results of randomized trials, there have been several attempts to evaluate the effects of PSA screening on survival and other parameters. Most of these studies are listed in “Related News.”

The current study looked at cancer mortality statistics from the Cancer Research U.K. and from the U.S. National Cancer Institute Surveillance, Epidemiology and End Results (SEER) programs. These authors reported the main findings of this study:

• In 2001 57% of U.S. men 50 years of age or older had PSA screening compared with 6% of U.K. men.
• Incidence rates for prostate cancer between 1975 and 2003 were 2.5 times higher in the United States.
• Death from any cancer is similar between the United States and United Kingdom.
• Prostate cancers deaths in the United States and United Kingdom were similar in the early 1990s.
• Prostate cancer deaths declined by 4.2% per year after 1994 in the United States compared with a decline of 1.1% per year in the United Kingdom.
• Mortality in patients 75 years of age or older had a 5.3% per year decline in deaths in the United States, while prostate cancer deaths in this group in the United Kingdom leveled out.

Comments: These authors had several possible explanations for these findings but none were really satisfactory. These findings are difficult to interpret. Men in the United Kingdom have similar rates of death from types of cancer as men in the United States and have a higher average life expectancy. It is difficult to see how PSA testing explains this phenomenon, as one would expect a 20-year lag between the onset of effective screening and a significant impact on deaths from prostate cancer.

Related News:

Ninety Percent of Prostate Cancers Detected by PSA Screening are Deemed Clinically Significant (3/24/2006)

Does PSA Screening Improve Survival? (1/13/2006)

Early Intervention Improves Survival Compared with Watchful Waiting in Early Prostate Cancer (3/3/2006)

Men With Screen Detected Prostate Cancer Have More Indolent Recurrences (11/2/2005)

Case-Control Study Suggests PSA Screening Decreases Risk of Metastatic Prostate Cancer (8/29/2005)

Prostate Mortality Decline Likely Due to PSA Testing (3/10/2003)

Screening with Prostate Specific Antigen May Not Decrease Prostate Cancer Deaths (10/15/2002)

Reference:

¹ Collin SM, Martin RM, Metcalfe C, et al. Prostate-cancer mortality in the USA and UK in 1975-2004: an ecological study. Lancet Oncology [early online publication]. April 17, 2008.