http://www.dailymail.co.uk/health/article-197283/Stress-doubles-breast-cancer.html
Stress doubles breast cancer
by BEEZY MARSH, Daily Mail
Women who suffer stress are twice as likely to develop breast cancer, a study suggests.
Worries about work and family, which lead to tension, fear, anxiety and sleep disturbance, appear to raise the risk of suffering the disease later in life.
The damaging effect of stress is on a par with recently documented dangers of taking HRT - which also doubles the risk of breast cancer.
The findings are a blow for a generation of women who face growing levels of stress due to trying to balance work and home lives.
They may also help to explain the rises in breast cancer incidence-But the results are controversial, as the study is the best evidence so far of the power of feelings to trigger disease - a theory which is discounted by many medics.
Doctors from the Sahlgrenska Academy in Gothenburg, Sweden, carried out a 24-year study of almost 1,500 women to make the unprecedented findings.
Their research will be presented at the European Cancer Conference in Copenhagen today.
The group of healthy women aged 38 to 60 were examined by doctors 35 years ago, during 1968 and 1969. They were also questioned about their stress levels over the previous five years.
Women had follow-up examinations during 1974, 1980 and 1992. After the final check-ups, doctors compared which women had suffered more breast cancer.
Those who had reported stress for a month or more during the five years preceding the start of the study had double the risk.
Other factors which would almost certainly increase the risk of disease - including smoking, weight, alcohol intake, age of first pregnancy and age at the menopause - were all taken into account.
Yet still the increase in breast cancer risk remained, with stress the only obvious causal factor.
Cases in the UK have reached an alltime high, with more than 40,000 women affected every year and 13,000 lives lost.
Lead author Dr Osten Helgesson said: "This study showed a statistically significant, positive relationship between stress and breast cancer."
Out of 1,350 women for whom there was complete data, 456 reported stress and 24 of them - or 5.26 per cent - developed breast cancer.
A total of 894 said they had no stress and 23 - or 2.5 per cent of them - developed the disease.
Therefore, researchers concluded, the risk of breast cancer was doubled among the stressed women.
However, Dr Helgesson said one weakness was the study did not try to pinpoint exactly how much stress was needed to cause the disease.
He added: "I would emphasise that more research needs to be carried out before it can be said that stress definitely increases a woman's risk."
Some experts believe the link could be due to hormonal changes which the body undergoes at times of stress.
Breast cancer is largely a disease driven by the hormone oestrogen, and it is possible that feelings of stress could cause changes in hormone levels which then affect healthy cell growth within the breast.
Stress is thought to lead to changes in the immune system - which could damage the body's ability to kill off cancerous cells, allowing disease to proliferate.
Delyth Morgan, chief executive of the charity Breakthrough Breast Cancer said: "Further research is needed before any direct association between stress and increased breast cancer risk is confirmed."
Women with breast cancer have a dramatically improved chance of survival if they are given the hormone treatment tamoxifen, experts said yesterday.
Taking the drug for five years leads to a 30 per cent reduction in the death rate 15 years after breast cancer is first diagnosed.
Leading epidemiologist Professor Sir Richard Peto said results are so convincing that experts should look into giving tamoxifen for longer - in the hope of furthering survival of cancer victims.
Breast cancer death rates have tumbled over the past two decades due to early diagnosis, better treatment and the use of treatments such as tamoxifen.
Around 13,000 women died of breast cancer in 2001, but that was a fall of 21 per cent over the last decade.
Although the actual number of cases of the disease has increased, their chances of survival are better than ever.
Sir Richard said the latest studies show 35 per cent of breast cancer sufferers who were not given tamoxifen died within 15 years.
But only 25 per cent of sufferers who were given five years of tamoxifen had died 15 years after their disease was diagnosed. Breast cancer in most cases is driven by the female hormone oestrogen and tamoxifen is an anti-oestrogen drug.
