Just seen an interesting article showing that breast cancer rates in
the US fell by 7% in 2003. An abstract presented at the 29th Annual
San Antonio Breast Cancer Symposium can be found
at http://www.abstracts2view.com/sabcs06/view.php?nu=SABCS06L_766
. The text reads:
-----------------------------
A sharp decrease in breast cancer incidence in the United States in 2003.
Ravdin PM, Cronin KA, Howlander N, Chlebowski RT, Berry DA.. MD
Anderson; National Cancer Institute; Harbor UCLA Medical Center
Introduction: The epidemiology of breast cancer may provide useful
insights into risk factors for this disease, and the impact of
various interventions on this diseases incidence and mortality.
Modeling efforts, such as those of the Cancer Intervention and
Surveillance Modeling Network (CISNET) have provided insight into the
relative impact of screening and adjuvant therapy on these endpoints
(NEJM 353:1784-1792,2005). Although randomized clinical trials such
as those investigating the impact of hormone therapy, diet, and
exercise provide the strongest evidence as to the influence of these
factors, epidemiologically based models, particularly when there is a
large change in these factors, may allow additional insights.
Methods: SEER public use data from 1990 to the end of 2003 was used
in these analyses.
Results: Breast cancer incidence in the United States gradually
increased at 1.7% per year from 1990 to 1998. Between 1998 and 2003
incidence began to decrease at 1% per year. In 2003 there was a 7%
decrease in incidence within a single year. This marked decrease was
seen both for in situ cancers (5.5%) and malignant cancers (7.3%). In
order to gain additional insight as the possible reasons for the
decline in incidence of breast cancer we conducted further subset
analyses. The steep decline seemed to begin in early 2003 with
relative rates (compared to a 2000/2001) showing a 1% decline in the
first and second halves of 2002, 6% in the first half of 2003, and 9%
in the second half of the year. The decline in incidence in 2003
relative to 2000/2001 was most evident in patients older than 50 (a
1%, 11%, 11%, and 7% decline in incidence for women in their 40s,
50s, 60s, and 70s respectively). The decline in incidence in ER
positive invasive tumors was greater than ER negative tumors (8%
versus 4%). When the analysis was restricted to patients 50-69 years
of age this difference in decline in the incidence by ER was more
striking (12% versus 4%).
Conclusions: In 2003 a steep decrease in the incidence of breast
cancer occurred in the United States. This decrease was most evident
in patients older than 50, and largely occurred because of a decrease
in the incidence of estrogen receptor positive breast cancer. Trends
in use of hormone therapy (which decreased markedly in late 2002
following the publication of Womens Health Initiative results) and
other medications potentially linked to breast cancer risk will be
discussed in this context.
Thursday, December 14, 2006 10:45 AM
General Session 1 (9:45 AM-11:00 AM)
A news report can be found at
<http://news.yahoo.com/s/ap/20061215/ap_on_he_me/breast_cancer_15>http://news.yahoo.com/s/ap/20061215/ap_on_he_me/breast_cancer_15
------------------------------
It has been suggested that the sharpest decline was in women over 50
and is due to a 50% drop in HRT in 2002.
Does anyone have any thoughts about whether another cause of lower
breast cancer rates in the over 50s just might be because
breastfeeding rates started to increase in a meaningful way in the US
about 25 years earlier?
Pamela Morrison IBCLC
Rustington, England
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