People with cancer who are depressed are more likely to die than
are patients with good mental health, psychologists reported Monday
in the science journal Cancer.
The study reported that death rates from cancer "were up to 25% higher in patients experiencing depressive symptoms and up
to 39% higher in patients diagnosed with major or minor
"In both of those groups, you can predict cancer mortality,"
lead researcher Jillian Satin, of the University of British
Columbia here, told AFP.
Link between cancer and mental health
While the study's main conclusion is a call for more research on
the links between cancer and mental health, Satin said the results
also proves the link is significant.
"I think depression should always be taken seriously," she
added. "It would be my wish that this line of research fuels adding
psychological social treatment into standard cancer care."
How the study was done
The study by Satin and co-authors Wolfgang Linden and Melanie
Phillips was an overview, called a meta-analysis, of 26 previous
studies on the effect of depression on the progression of cancer
and survival rates in of 9,417 patients.
Satin said the researchers controlled for the chicken-or-egg
factor: Do people become depressed because they are sick with
cancer? Or does cancer kill them more often when they have
depression independent of the cancer?
"That's the million-dollar question," she said. "Even after
correcting for that, we still see the positive relationship between
depression predicting mortality."
But Satin warned, "I want people to be cautious about this. We
have not shown that depression itself causes mortality but we
have a suggestion that this is possible."
Satin cautioned against trying to match a specific patient's
likelihood of death with the startling finding that death rates can
be up to 39% higher with depression that is serious enough
to be diagnosed.
"I know people want to know numbers, but I find them kind of
misleading," she said. "What this is saying is that somebody's
depressive status shortly after they are diagnosed with cancer
predicts cancer outcomes."
Evidence vs. belief
The published study said its goal was to determine whether
empirical evidence supports the widespread belief by both the
public and cancer specialists that a patient's state of mind
affects the outcome of disease.
"The field of psycho-oncology has experienced exponential
growth," noted the study. "Eighty-five percent of cancer patients
and 71.4% of oncologists endorse the belief that
psychological variables affect cancer."
Satin and her co-authors noted that other researchers earlier
linked heart disease, depression and higher risk of death.
"Depressed patients with coronary heart disease have a two-times
greater risk of mortality than nondepressed patients after
adjusting for clinical factors," they noted, citing another study.
The journal Cancer is the peer-reviewed science journal of the
American Cancer Society. – (SAPA, September 2009)
Height, cancer link grows stronger