There may be another explanation for the recently announced decline in breast cancer rates. And it's not nearly as promising as the first explanation may be.

A day after researchers announced that the significant drop in breast cancer cases is primarily due to fewer women using hormone replacement therapy (HRT), some experts suggest breast cancer rates are not dropping at all. Just as many women may have breast cancer, they say. They just aren't being screened for it.

"We have been aware for several years that the number of radiologists who specialize in mammography have been decreasing, and that there are places in the United States where women have difficulty getting access to mammography," Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, wrote on the society's blog just after the public announcement.

"If mammography use has reached a peak and is now decreasing, we may actually be diagnosing fewer cancers when they can be most effectively treated, Lichtenfeld said. "If you don't get a mammogram, you don't diagnose a cancer."

The research linking the decline in HRT to the drop in breast cancer came from the M.D. Anderson Cancer Center in Houston and was discussed at a breast cancer conference in San Antonio on Thursday. The research, based on a report by the National Cancer Institute, showed a seven percent drop in new breast cancer cases between July 2002 and August 2003, corresponding with the results of a 2002 Women's Health Initiative study.

With media reports citing HRT as the direct cause of the drop, some worry the public is getting the wrong message -- specifically women still taking hormones or those who have taken them in the past. While women not taking hormones are breathing a sigh of relief, others are in a panic.

Dr. Katherine Sherif, director of the Drexel Center for Women's Health at Drexel University College of Medicine in Philadelphia, has spoken already with 15 patients worried about this news.

"What I have told them is that three years is too short of a time to measure the effects of a drug on breast cancer," she said. "Cancers take decades to develop, and conversely, withdrawing hormones could not result in a decrease in breast cancer in three years -- it's actually absurdly short." There are also concerns women will experience anxiety about other therapies using estrogen, such as in vitro fertilization (IVF).

The study on HRT and breast cancer may be raising more questions than answers -- which could be a good thing. More questions prompt more investigation, more study, more research. And this will hopefully help us figure out one facet of the mystery of breast cancer.

Previous posts on the topic of HRT and breast cancer are as follows.

• HRT use drops breast cancer rates drop
• Hooray for HRT!?
• HRT and smoking dramatically increases breast cancer risk
• HRT increases breast cancer risks