Mum gets endometrial cancer after taking tamoxifen to beat breast cancer

Lisa Evans developed endometrial cancer after taking tamoxifen to keep the risk of her breast cancer returning low. Photo / Channel 9

When Aussie mum Lisa Evans fought off breast cancer, she was rightly relieved.

But the Perth woman has been dealt another blow after a drug that helped her fight off the disease led to her developing another form of cancer.

She has just spent her five-year “cancerversary” recovering from an operation to tackle endometrial cancer.

Evans is now urging people to look past the “rare” second diagnosis and look at the benefits of the drug tamoxifen.

“You go on a drug to limit your chances of breast cancer again but then it gives you a higher risk of endometrial cancer,” she told 9 News.

Tamoxifen is prescribed both to patients with breast cancer as a form of treatment and to cancer-free patients to prevent breast cancer from returning.

It is only effective in the hormone receptor-positive form of the disease and works by blocking oestrogen from attaching to cancer cells in the breast, stopping the cells from receiving signals to grow and multiply.

The drug can lower the risk of breast cancer recurrence in premenopausal women by 30-50 per cent and by 40-50 per cent in postmenopausal women, according to the Cleveland Clinic.

Despite her diagnosis of early-stage endometrial cancer, Evans is staying positive and recommending people consider the treatment.

“My friends say how do I feel? I say clearly I’m an overachiever,” she joked to 9 News.

Studies have found that the risk of women developing endometrial cancer when taking the drug is two to three times higher, according to the American College of Obstetricians and Gynecologists.

Cancer Australia has described the risk of endometrial cancer as “consistently higher” for women taking tamoxifen, especially for those older than 50.

“The risk of endometrial cancer increases with longer use of tamoxifen. In women who take tamoxifen for 10 years, the risk of endometrial cancer is twice as high as the risk in women who take tamoxifen for 5 years,” it said.

The organisation urges patients to take a look at both the potential risks and benefits of tamoxifen before deciding to take it.

“Taking tamoxifen is an important adjuvant therapy and women should balance the important benefits of reducing breast cancer recurrence with any rare side effects including the increased risk of endometrial cancer.,” it said.