|
In a large screening study, men with
baseline levels of prostate-specific antigen (PSA) <2 ng/mL
had a very low risk of conversion to positive PSA (>4 ng/mL)
at subsequent screenings. Dr. Crawford recommended that men
who want prostate cancer screening but have low PSA levels should
seek screening less frequently. In the United States, adopting
this strategy would save hundreds of millions of dollars.
Prostate cancer is the most common cancer diagnosis in American
males and the second leading cause of cancer death. Strategies
to improve these statistics include prevention, screening,
and new treatments for locally advanced or metastatic disease.
In 1993, the National Cancer Institute in the United States
started the Prostate, Lung, Colorectal and Ovarian Cancer
(PLCO) screening trial. Between 1993 and 2001, investigators
enrolled 154,000 men and women ranging in age from 55 to 74
years. They randomized patients to a screening or usual care
arm.
One aim of the PLCO trial is to evaluate the value of prostate
cancer screening. Men received PSA assessments at each of
6 annual screenings. They also received a digital rectal examination
for the first four yearly exams.
Dr. Crawford presented an early analysis of prostate cancer
screening data from the PLCO study. Investigators evaluated
total PSA changes over 5 years for men who had baseline PSA
levels <4 ng/mL and at least one follow-up screening. This
group included nearly 28,000 men.
The results showed that only 1.4% of men with PSA under
1ng/mL at baseline would become positive (i.e., PSA >4 ng/mL)
in 4 subsequent years of annual PSA testing. In addition,
only 1.2% of men with baseline PSA of 1-2 ng/mL would have
a positive PSA test in the following year screening.
|
The PLCO study: Rate of conversion
from negative
to positive PSA (> 4 ng/mL) within 1 year
PSA
level (ng/mL) | Conversion
rate | 0-1 | 0.25% | 1-1.9 | 1.2% | 2-2.9 | 34% | 3-3.9 | 83% |
|
Elevations in PSA found during routine screening may lead
to significant anxiety due to false positive results and to
the need for needle biopsies to rule out malignancy. Investigators
believe the results of this study could help men choose whether
or not to undergo routine prostate cancer screening.
Dr. Crawford said 55% of PSA tests could be avoided if men
with PSA <1 ng/mL received screening only every 5 years, and
men with PSA between 1 and 2 received screening every 2 years.
Adopting this strategy would avoid 15.7 million fewer screenings,
and save up to $1 billion per year in the United States.
|
2000-2013 by HESCO International, Ltd. All rights reserved.