Cervical screening can spot signs of cancer developing

HPV is a sexually transmitted infection - but only a small percentage of women who catch it develop cancer.

US researchers, writing in the journal Annals of Behavioural Medicine, said that stressed women had a weaker immune response to the virus.

But the study did not prove that stress was the root cause of the problem.

Women who report feeling more stressed could be at greater risk of developing cervical cancer because their immune system can't fight off one of the most common viruses that cause it

Dr Carolyn Fang

Fox Chase Cancer Center

It is already known that the way the body's immune system reacts when confronted with HPV - short for human papillomavirus - can determine whether the infection causes more serious problems.

Many women appear able to "clear" the virus from their bodies, while in others it can cause a persistent infection which raises the risk of the abnormal cell changes which can eventually lead to cancer.

The latest study, carried out at the Fox Chase Cancer Center in Philadelphia, looked for reasons why, in some women, the immune system is unable to clear the virus.

Their small study asked 78 women who had had abnormal smear tests to fill in a questionnaire about their day-to-day stresses over the previous month, and any major events such as bereavements or divorce over a longer period.

Then the ability of their immune system to respond to HPV16 - the most common variety of the virus linked to cervical cancer - was measured.

Similar tests were carried out on 28 women who had not received an abnormal smear test, and the results compared.

The researchers found that the immune response was poorer among women who reported higher levels of day-to-day stress.

However, there was no correlation between immune response and the number of major events.

No cause

Dr Carolyn Fang, who led the study, said: "Women with higher levels of perceived stress were more likely to have an impaired immune response to HPV16.

"That means that women who report feeling more stressed could be at greater risk of developing cervical cancer because their immune system can't fight off one of the most common viruses that cause it."

The researchers admitted, however, that the design of the study meant that it was impossible to look for proof that stress actually caused the immune response, rather than just accompanied it.

A spokesman for Cancer Research UK said that more research would be needed to prove the link.

"We already know that an effective immune response against certain forms of HPV can guard against cervical cancer - this knowledge helped to spearhead the development of cervical cancer vaccines targeting this virus.

"This small study does not provide conclusive evidence that a stressful life directly suppresses the immune system and increases the risk of cervical cancer.

"More work would be needed before we know if there is a relationship between stress levels and the ability to fight HPV infection."