RISE IN BREAST CANCER INCIDENCE IN UK
Tuesday, February 15, 2011
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Although breast cancer mortality continues to fall, the incidence of breast cancer is increasing in the United Kingdom; the latest estimate for lifetime risk is now 1 in 8 (up from 1 in 9 ten years ago).
This new estimate, from Cancer Research UK, was widely reported in the media, with headlines emphasizing the frightening statistic of 1 in 8, but few reports explained that risk increases sharply with age.
Breast cancer rates have risen by 3.5% in 10 years, the organization reported. A diagnosis of breast cancer was recorded in 47,700 women in 2008, compared with 42,400 women in 1999.
The biggest rise was among women 50 to 69 years of age, where the increase was more than 6% in that 10-year period. This age group represents almost half (48%) the total number of cases. Another 33% of cases were diagnosed in women older than 70 years of age.
Only 19% of the total cases were diagnosed in younger women (25 to 49 years); in this age group, the rate of breast cancer actually dropped slightly (by 0.5%).
According to Cancer Research UK, "there's no simple answer" to why breast cancer rates are increasing, but more cancers being detected by mammography screening, lifestyle changes such as increased alcohol use and obesity, an aftermath of prolonged use of hormone replacement therapy, women having fewer children and breastfeeding less, and the increasing age of the population are possible explanations.
Age in particular has a major effect. The risk for breast cancer increases sharply from around the time of the menopause and continues to rise with increasing age.
Risk for Breast Cancer by Age
All of these potential explanations, along with several others, are discussed in some detail on a science blog on the Cancer Research UK Web site.
Change in Mammography Policy
These latest figures chart a rise from 1999 to 2008, but about halfway through that period (in 2004), there was a change in national policy in the United Kingdom, when women 65 to 69 years of age started to be included in the national screening breast screening program. Before 2004, invitations for mammograms stopped when women reached 65 years of age (they start at 50 years).
The rise in breast cancer diagnoses in this age group probably coincides with this, according to the organization, because an increase in the number of women being screened would very likely lead to more cancers being detected.
Cancer Research UK acknowledges the controversy that has raged over mammography leading to the overdiagnosis of breast cancer, in particular the fact that it picks up cases of ductal carcinoma in situ (DCIS), which might never develop into a problem. "But our new analysis doesn't include cases of DCIS, so these noninvasive tumors can't explain the rising breast cancer rates in women aged 65 to 69," it reports.
Now for the Good News
"While it's worrying that women are now more likely to develop breast cancer than they were a decade ago, there is good news too," Cancer Research UK explains, pointing out that survival rates have "shot up."
"Almost 2 out of every 3 women with breast cancer now survive the disease beyond 20 years, compared with less than half in the 1990s. And more than three quarters of women diagnosed with breast cancer survive for at least 10 years, or more," it notes.
This new estimate, from Cancer Research UK, was widely reported in the media, with headlines emphasizing the frightening statistic of 1 in 8, but few reports explained that risk increases sharply with age.
Breast cancer rates have risen by 3.5% in 10 years, the organization reported. A diagnosis of breast cancer was recorded in 47,700 women in 2008, compared with 42,400 women in 1999.
The biggest rise was among women 50 to 69 years of age, where the increase was more than 6% in that 10-year period. This age group represents almost half (48%) the total number of cases. Another 33% of cases were diagnosed in women older than 70 years of age.
Only 19% of the total cases were diagnosed in younger women (25 to 49 years); in this age group, the rate of breast cancer actually dropped slightly (by 0.5%).
According to Cancer Research UK, "there's no simple answer" to why breast cancer rates are increasing, but more cancers being detected by mammography screening, lifestyle changes such as increased alcohol use and obesity, an aftermath of prolonged use of hormone replacement therapy, women having fewer children and breastfeeding less, and the increasing age of the population are possible explanations.
Age in particular has a major effect. The risk for breast cancer increases sharply from around the time of the menopause and continues to rise with increasing age.
Risk for Breast Cancer by Age
| Age (Years) | Risk |
| 29 | 1 in 2000 |
| 39 | 1 in 215 |
| 49 | 1 in 50 |
| 59 | 1 in 22 |
| 69 | 1 in 13 |
| Lifetime risk | 1 in 8 |
All of these potential explanations, along with several others, are discussed in some detail on a science blog on the Cancer Research UK Web site.
Change in Mammography Policy
These latest figures chart a rise from 1999 to 2008, but about halfway through that period (in 2004), there was a change in national policy in the United Kingdom, when women 65 to 69 years of age started to be included in the national screening breast screening program. Before 2004, invitations for mammograms stopped when women reached 65 years of age (they start at 50 years).
The rise in breast cancer diagnoses in this age group probably coincides with this, according to the organization, because an increase in the number of women being screened would very likely lead to more cancers being detected.
Cancer Research UK acknowledges the controversy that has raged over mammography leading to the overdiagnosis of breast cancer, in particular the fact that it picks up cases of ductal carcinoma in situ (DCIS), which might never develop into a problem. "But our new analysis doesn't include cases of DCIS, so these noninvasive tumors can't explain the rising breast cancer rates in women aged 65 to 69," it reports.
Now for the Good News
"While it's worrying that women are now more likely to develop breast cancer than they were a decade ago, there is good news too," Cancer Research UK explains, pointing out that survival rates have "shot up."
"Almost 2 out of every 3 women with breast cancer now survive the disease beyond 20 years, compared with less than half in the 1990s. And more than three quarters of women diagnosed with breast cancer survive for at least 10 years, or more," it notes.
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