Sudden Decline in Breast Cancer Could Be Linked to HRT

[الدكتور أحمد باذيب]

	Sudden Decline in Breast Cancer Could Be Linked to HRT Allison Gandey December 14, 2006 (San Antonio) –- Breast cancer rates appear to be dropping — especially in women over the age of 50 years — and new research presented today suggests this surprising decline may be due to recent changes in hormone replacement therapy (HRT) use. Reporting here at the 29th Annual San Antonio Breast Cancer Symposium (SABC), researchers showed a 7% drop in disease rates in 2003 — a dramatic fall that never before has been observed in a single year. "Something went right in 2003," lead investigator Peter Ravdin, MD, from the MD Anderson Cancer Center in Houston, Texas, told reporters. "It seems that it was the decrease in the use of hormone therapy, but from the data we used we can only indirectly infer that is the case." If this proves to be true, Dr. Ravdin noted, "the tumor growth effect of stopping hormone replacement therapy is very dramatic over a short period of time, making the difference between whether a tumor is detected on a mammogram or not." During the question period following the session, attendees called the findings "fascinating" and "provocative." Another research team reporting in a recent issue of the Journal of Clinical Oncology came to similar conclusions (Clarke CA et al. J Clin Oncol. 2006;24:e49-50). "Hormone therapy use dropped 68% between 2001 and 2003, and shortly thereafter we saw breast cancer rates drop by 10% to 11%," lead author Christina A. Clarke, MD, from the Northern California Cancer Center, in Fremont, said in a news release. "This drop was sustained in 2004, which tells us that the decline wasn't just a fluke." In the new study presented here, Dr. Ravdin and his team from the National Cancer Institute and Harbor-University of California, Los Angeles Medical Center looked at 9 regions in the United States. Analyzing data from the Surveillance Epidemiology and End Results (SEER) database, they found that the incidence of breast cancer increased 1.7% per year from 1990 to 1998. But then rates began to decline, and between 1998 and 2003, the incidence decreased by 1% each year. Decrease Greater in ER-Positive Invasive Tumors The sharpest drop of 7% was observed in 2003. This decline was seen both for in situ cancers (5.5%) and malignant cancers (7.3%). The researchers report that the decrease in incidence was greater in ER-positive invasive tumors than ER-negative tumors (8% vs 4%). When the analysis was restricted to patients 50 to 69 years of age, this difference in decline in the incidence by ER was more striking (12% vs 4%). "The researchers present a very positive message about incidence," session comoderator Martine Piccart-Gebhart, MD, from the Jules Bordet Institute, in Brussels, Belgium, said during the meeting. This positive message surprised even the team itself. In an MD Anderson news release, senior author Donald Berry, PhD, admitted that he did not expect to observe the magnitude and the rapidity of the decline in incidence. But, he added, it makes perfect sense if it is considered that use of hormone therapy may be an important contributing factor to breast cancer development. Research suggests that ER-positive tumors will stop growing if they are deprived of hormones. Dr. Ravdin estimates that about 30% of women over the age of 50 years had been taking hormone replacement therapy in the early years of the new millennium and that about half of these stopped treatment in late 2002 after the results of the Women's Health Initiative study were announced. That trial looked at more than 16,000 women over the age of 50 years using hormone replacement therapy and was prematurely stopped when the combination of estrogen and progestin was found to significantly increase the risk of developing invasive breast cancer. "It is possible that a significant decrease in breast cancer can be seen if so many women stopped using therapy," Dr. Ravdin said. "But whatever the cause," he said at the meeting, "we know that this decline is a real effect, not just a statistical anomaly." 29th Annual SABC: Abstract 5. Presented December 14, 2006. Related Links Conference Coverage 29th Annual San Antonio Breast Cancer Symposium Resource Centers Breast Cancer Menopause --------------------------------------------------------------------------------