Behind the headlines: Why is breast cancer more common?

Breast cancer rates are rising, but the reasons are not entirely clear, finds Emma Baines

Women should check their breasts for abnormalities on a regular basis
Women should check their breasts for abnormalities on a regular basis

What is the story?  

Modern lifestyles are to blame for ‘frightening’ increases in rates of breast cancer in the UK, the media has reported.  

The reports cited figures from 2004 showing that breast cancer rates have risen by more than 80 per cent since 1971.  

There were 41,000 cases of the disease diagnosed in the UK in 2004. Breast cancer now accounts for one in three of all cancers diagnosed in women, the papers said. The life choices of modern working women were to blame for this trend, the media added.  

Having fewer children, putting off childbirth until later in life and not breastfeeding were all factors in the alarming rise in breast cancer incidence.  

Obesity, increased consumption of alcohol and hormone treatments such as the birth control pill and HRT were also factors, according to the reports.    

What are the figures?  

The reports are based on figures released by the Office of National Statistics (ONS) at the end of last month, showing the number of patients diagnosed with cancer in England during 2004.  

Breast cancer was the most common, affecting over 37,000 patients. The second most common was prostate cancer, which affected over 29,400 men.  

Overall, the number of cases of cancer diagnosed per year has risen by 21 per cent in men and 41 per cent in women since 1971. However, the number of breast cancer cases diagnosed per year has risen at an even greater rate than other cancers. There were 81 per cent more breast cancer diagnoses in 2004 than in 1971.  

But as breast cancer diagnosis rates have risen, mortality rates have fallen. The average five-year survival rate is now 80 per cent.  

However, breast cancer is still the most common cause of cancer death in women, accounting for 29 in every 100,000 deaths.  

What is the explanation?  

According to Dr Colin Smith, a statistician at Cancer Research UK, part of the reason for the increase in breast cancer diagnoses is the success of the national breast screening programme.  

‘The diagnosis rate for women targeted by the programme, aged 50–64, has gone up more than for other age groups.  This indicates that the programme is bringing to light cases that would otherwise have gone undetected until years later,’ he said.  

Other reasons for the increase are related to the ways the average woman’s reproductive history today are different from women of the 1970s. 

An earlier age of first period, later first pregnancy, lower number of live-born children and late menopause are all factors that increase breast cancer risk. Oral contraception, HRT, obesity and increased alcohol consumption also contribute to increased risk. 

In addition, some occupations are associated with higher breast cancer risk than others. Several studies have found increased risks of breast cancer in women working as teachers, clerical and administrative workers and telephone and radio operators.  

‘There is a probable link between a sedentary lifestyle and an increased risk of breast cancer,’ Dr Smith explained.   

Other studies have indicated that farmers may be at increased breast cancer risk because of exposure to organochlorines used in pesticides, which mimic oestrogen and may cause breast cancer. But the evidence supporting this association is poor.  

What do other experts say?  

Dr Sarah Cant, a senior policy officer at charity, Breakthrough Breast Cancer, said: ‘The screening programme, introduced in the late 1980s, picks up many more breast cancers in women over 50 that would not otherwise have been picked up.’  

She added that although life-style factors did play a part in the increased breast cancer risk, it was hard to pin down the main causes. 

‘We don’t actually know all of the causes of breast cancer.’  

She said that Breakthrough Breast Cancer had launched a 40-year study, The Breakthrough Generations Study, which was designed to find out the causes of breast cancer. 

‘Until then we recommend that women live a healthy lifestyle, eating a balanced diet, taking exercise and drinking moderate amounts of alcohol.’  

She said it was important for all women to be breast aware, checking their breasts for abnormalities on a regular basis, and to be sure that they always attend breast screening appointments.  

Informing patients  

Breast cancer rates have been rising over the past 30 years.  

This is likely to be an effect of living in a more prosperous society.  

Women are much less likely to die from the disease now than 30 years ago.  

Women can minimise the risk of breast cancer by maintaining a healthy weight, drinking alcohol only in moderation and attending breast screening appointments.  

what the papers said  

“Breast cancer up 80% in 30 years”  

The TImes  

“Riddle of ‘frightening’ breast cancer epidemic”  

Daily Mail  

“Breast cancer case rise 80% since Seventies”  


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