Some women using the therapy, also known as bio-identical hormones, have suffered elevated hormone levels that could lead to excessive bleeding, increased risk of breast and uterine cancer and blood clots.

Dr John Eden, director of the Sydney Menopause Centre at Randwick’s Royal Hospital for Women, said in the past year he had referred two cases of uterine cancer in patients who had been taking natural hormone replacement therapy, to the Therapeutic Goods Administration.

Dr Eden said these “handmade hormones” were prepared by chemists – known as compounding chemists – without scrutiny. Although the process is legal, it is beyond the regulatory control of the TGA and state-based pharmacy boards. “There’s a whole stack of women being treated out there with handmade hormones. It’s untested hormone replacement therapy,” he said. “Many women think they are getting a herbal treatment and are shocked to learn they are getting a hormone treatment.”

One of the NHRT’s major wholesalers, Professional Compounding Chemists of Australia, defended the practice, citing an exemption in the TGA Act that allows the preparation of medicines for individuals. The medication is usually made into troches, or lozenges, with the hormones absorbed through the lining of the mouth.

NHRT contains the female hormones oestrogen and progesterone, sourced from yams or soy and synthesised in laboratories. However, NHRT can also include the male hormone testosterone, which has not been approved in Australia for use on women. Some compounds also include thyroid hormone, the little-understood sex steroid pregnenolone and a steroid called DHEA, which converts to testosterone and is banned from manufacture in Australia.

Dr Helena Teede, research director at Australia’s leading women’s health organisation, the Jean Hailes Foundation, said many women were unaware preparations were not approved by the TGA.

“There has been very limited research into these preparations and women taking the compounds are essentially guinea pigs,” she said.

A leading compounding chemist Richard Stenlake, in Bondi Junction, said he would welcome more regulation of the industry and there were discussions taking place about how it could be done.

Mr Stenlake said he was one of the few compounding chemists with the expertise to do regular testing of NHRT preparations to make sure there was the correct dose of hormones.

“There should be parameters put on compounding pharmacists that drug companies face,” he said. “You have to make sure the dose prescribed by the doctor is the dose that goes out to the patient.”

The PCCA defended the safety of the practice, citing an exemption in the TGA Act which allows the preparation of medicines for individuals. However, it acknowledged in a written statement there was no formal testing of the products.

“Since compounded products are made on an individual basis according to the needs of a specific patient, it is not possible to test each product before supply to a patient without making the cost prohibitive. Many pharmacies do test samples of products that are made frequently,” it said in the statement.

The study showed that 1.8 percent, or about one in 50, of newly diagnosed endometrial cancer patients have mutations for Lynch syndrome, an inherited condition also known as hereditary nonpolyposis colon cancer, or HNPCC.

People with Lynch syndrome mutations are at high risk for colon, endometrial, ovarian and gastric cancer. Endometrial, or uterine, cancer is the most common cancer in women with this condition.

The study is the first to comprehensively screen a large number of women with uterine cancer for Lynch syndrome mutations, said Heather Hampel, a genetic counselor in the clinical cancer genetics program and first author of the study.

“It’s important to identify women with one of these mutations because they have a very high risk for developing colon cancer, and they may not be aware of that risk,” said Hampel. “Because this is hereditary, half of her siblings and children may also be at risk for the syndrome.

“For this reason, the relatives of a person with Lynch syndrome should also be screened for the responsible gene mutation,” said Hampel, a clinical assistant professor in the department of internal medicine.

Family members who also have the mutation need close monitoring for early cancer detection, including an annual colonoscopy starting at age 25 and endometrial cancer screening (using ultrasounds and biopsies) starting at age 30, Hampel said.

Family members without the mutation can follow the American Cancer Society’s guidelines for colorectal cancer screening, which call for a colonoscopy every 10 years starting at age 50 and no routine endometrial cancer screening, she said.

This study involving 543 women was led by Albert de la Chapelle, co-leader of the OSUCCC Molecular Biology and Cancer Genetics Program. Participants in the study were diagnosed and treated for endometrial cancer at the three major hospital systems in Columbus, Ohio, between 1999 and 2003.

To learn the frequency of Lynch syndrome mutations among all newly diagnosed endometrial cancer patients, the researchers tested tissue from the tumors from each patient for MSI (microsatellite instability), a change in the DNA of tumor cells that occurs in more than 90 percent of Lynch syndrome tumors. Of the 543 tumors tested, 118 showed MSI. Because these patients are more likely to have Lynch syndrome, they participated in the gene testing portion of the study and nine (1.8 percent) were found to have Lynch syndrome mutations.

In addition, the researchers used another technique called immunohistochemistry, to prescreen the tumors for mutations. Follow-up gene testing performed on patients with abnormal immunohistochemistry results showed that one additional woman with an MSI-negative tumor also had a Lynch syndrome mutation.

Of the 10 Lynch syndrome patients, seven did not meet the usual criteria for diagnosing the hereditary condition. That diagnosis is largely based on family history and age. Ordinarily, these seven cases would have gone undiagnosed.

In addition, the counseling and testing of 21 relatives of the 10 women with Lynch syndrome revealed 10 additional people with Lynch syndrome mutations.

The study is the continuation of an Ohio State colon cancer study also led by de la Chapelle that was published in the New England Journal of Medicine in 2005. In that study, 2.2 percent of newly diagnosed colon cancer patients tested positive for Lynch syndrome.

That study recommended testing all newly diagnosed colon cancer patients for the inherited syndrome, Hampel said. As a result, Ohio State University Medical Center now routinely screens all newly diagnosed colon cancer patients to find those most likely to have Lynch syndrome using the immunohistochemistry test, Hampel said. She hopes for a similar change in the standard of care for endometrial cancer patients as well.

“We think such genetic testing should be nationwide on all colon cancer and endometrial cancer patients, but further cost-benefit analysis and study is needed first,” Hampel said. “Screening for Lynch syndrome can save lives.”

Those that have the inherited mutation called Lynch syndrome have a higher risk of developing colon, endometrial, ovarian and gastric cancer. The most common cancer for this condition is endometrial cancer.

It is important for women diagnosed with endometrial cancer to be tested for the Lynch syndrome mutation. These women can benefit from knowing that they are at high risk for other cancers by being proactive and making sure they get the correct screening tests on an annual basis.