US breast cancer decrease tied to drop in hormone replacement therapy use

Investigators reported a remarkable 7 percent relative decline in breast cancer incidence between 2002 and 2003, with a steeper decline of 12 percent in women between the ages of 50 and 69 diagnosed with estrogen receptor positive breast cancer, that is, breast cancer that is hormone-dependent for tumor growth. The findings were presented at the 29th annual San Antonio Breast Cancer Symposium.

“It is the largest single drop in breast cancer incidence within a single year I am aware of,” said Dr. Peter Ravdin, a research professor at M.D. Anderson, in a press release. Ravdin added that the study can only indirectly infer the connection between the decline in breast cancer and stopping the use of HRT.

“But if it is true, the tumor growth effect of stopping use of HRT is very dramatic over a short period of time, making the difference between whether a tumor is detected on a mammogram in 2003 or not,” asserted Ravdin. He added, however, that what it is not known is whether these tumors will regress and never become a problem or just take longer to show up.

The overall 7 percent decline represented, according to the researchers, some 14,000 fewer women who were diagnosed with breast cancer in 2003 than in 2002, a year in which some 203,500 new cases were diagnosed.

According to the M.D. Anderson analysis, the rate of breast cancer diagnoses increased steadily at 1.7 percent annually from 1990 to 1998, before decreasing to 1 percent a year from 1998 to 2002. By the end of 2003, the rate had dropped 7 percent when age adjustments were made.

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http://wsws.org/articles/2006/dec2006/canc-d21.shtml