There is no truth in the belief - based on anecdotal evidence - that cancer patients can delay their death for important events, a US study suggests.
Study found no unusual death patterns around Christmas
An Ohio State University team looked at 300,000 cancer deaths over 12 years.
They found no evidence of unusual death rate patterns near birthdays, Christmas and Thanksgiving, they told the Journal of the American Medical Association
Many carers tell of patients who seem to defy the odds by staying alive long enough to witness an important event.
Health care workers and others close to patients dying of cancer commonly recall how they die immediately afterwards.
And previous studies have noted an apparent dip or peak death pattern associated with significant religious and social events.
Some believe that patients are able to cheat death by sheer willpower alone, or perhaps by some unknown psychosomatic mechanism.
However, the latest analysis showed no significant difference in the proportion of patients dying in the week after a potentially significant event, compared with the proportion dying the in the week before it.
In fact, women were more likely to die of cancer in the week before their birthday, than the week after it.
Researcher Dr Donn Young said: "I think all of us may know or have heard of someone 'hanging on' through the holidays or trying to live until an important occasion.
"But the figures just don't bear this out as something that people can really do.
"I think the most important thing for all of us to take away from this is the notion of attending to what is important.
"In other words, don't put off what is meaningful in life. Do it now, before it is too late."
A recent discussion paper in the journal Psychosomatic Medicine found previous studies which suggested there may be some truth to the theory were methodologically flawed.
None had provided any direct evidence of a psychophysiological mechanism enabling people to postpone or hasten their own death.
Professor Thomas Wise is an expert in psychiatry and behavioural sciences at Johns Hopkins University in Baltimore and editor of Psychosomatic Medicine.
He said: "The real reason why we hold to this theory is our wish to have control over the most sentinel event in our lives following birth - death."