Even though current guidelines advocate colorectal cancer
screenings for those with severe illnesses, they may bring
little benefit and may actually pose harm, according to
a recent study by Yale School of Medicine.
The study offers a new approach for assessing who is
likely to benefit from a screening so that screening recommendations
can be tailored more effectively to individual patients.
First author R. Scott Braithwaite, M.D., and his colleagues
developed a new method of evaluating medical screening
tests like colonoscopy, called the "payoff time,"
which is the minimum amount of time it takes for the benefits
from a test to exceed its harms (i.e., its complications
and side effects). The method can also be applied to patients
of any age and illness.
To estimate the payoff time for using colonoscopy to
screen for colorectal cancer, the team focused on two
patient groups that included 50-year-old men with HIV,
and 60-year-old women with congestive heart failure.
Braithwaite said the payoff time for colorectal cancer
screening was as long as five years for 50-year-old men
and as long as 2.9 years for 60-year-old women. Because
patients with severe congestive heart failure have a life
expectancy of less than 2.9 years, they were more likely
to be harmed than benefited by colorectal cancer screening,
say the researchers, whereas patients with HIV have a
life expectancy of greater than five years, so they were
likely to benefit from colorectal cancer screening.
"This issue is only becoming increasingly important
as pay-for-performance and physician 'report cards' encourage
clinicians to offer screening to everyone, regardless
of individual benefit," said Braithwaite, assistant
professor of medicine at Yale School of Medicine and at
the VA Connecticut Healthcare System. "This may have
the unintended consequence of harming patients with severe
Braithwaite added that the "cocktail" of therapies
that have revolutionized HIV care have increased life
expectancy so much that screening guidelines now apply
to patients with HIV.
Other authors on the study included John Concato, M.D.,
Chung Chou Chang, Mark S. Roberts, M.D. and Amy C. Justice,
The study was supported by a grant from the National
Institute of Alcohol Abuse and Alcoholism, National Institutes
Citation: Archives of Internal Medicine Vol. 167, No.
21 (November 26, 2007)