New Drug Provides Older Women With Significant Protection From Breast Cancer
Wed, April 21, 2021

New Drug Provides Older Women With Significant Protection From Breast Cancer

Scientists found that an estrogen-blocking drug can help older women reduce their risk of breast cancer / Photo by: siam.pukkato via Shutterstock

 

Scientists found that an estrogen-blocking drug can help older women reduce their risk of breast cancer. The drug known as Anastrozole was found to only work on post-menopausal women and offer protection for up to seven years after they stop taking it.

Anastrozole is given to women who either had breast cancer or are at a high risk of developing it because of their family's medical history. The drug helps block estrogen, which aids the growth of most tumors.


Longer Protection

A more popular brand of anastrozole is tamoxifen, which can decrease breast cancer risks by 28%, but a newer version was found to provide better results. In a study of 3,864 women around the world, published in The Lancet journal, anastrozole branded as Arimidex could provide better protection for a long period of time.

According to the Daily Mail, earlier studies found that anastrozole can reduce the risk of breast cancer in women by half if taken for five years. But the Lancet study revealed that the drug can extend its protection seven years—giving a total of 12 years of protection.

The women involved in the study took either anastrozole or a placebo for five years and were monitored for 12 years. Results show that the incidence of breast cancer was 49% lower in the half who were given the drug, even in participants who stopped taking it after the first five years. That's significantly better compared to the 28% lowered incidence recorded for tamoxifen.

"Previous research confirmed anastrozole is very effective while women are still taking the drug," said lead author Jack Cuzick. "But this is the only trial looking at whether it offers long term protection for women at high risk of developing breast cancer."

A more popular brand of anastrozole is tamoxifen, which can decrease breast cancer risks by 28%, but a newer version was found to provide better results / Photo by: Billion Photos via Shutterstock

 

Fewer Side Effects

Co-author Ivana Sestak said the results of their study indicate that one case of breast cancer will be prevented during a 12-year period in every 29 women who take anastrozole for five years. 

"Around 49 women would need to take tamoxifen for five years to prevent one breast cancer case during the same period," Sestak explained.

Moreover, the researchers also found that the new drug has fewer side effects. This means anastrozole offers can be an alternative for patients who don't want to feel hot flashes, have irregular periods, gain weight, or have their hair thinning out.

A significant number of women in the study (75%) were able to stick with taking the pill during the five-year period, suggesting that the side effects were not severe enough to stop the women from taking the drug. The same was found in 77% of the women in the placebo arm, a statement said.

"This study shows that there are no significant long term side-effects in the five years after completion of anastrozole, particularly no increase in fractures or heart disease," said Tony Howell, the clinical lead from the University of Manchester.

The researchers said more follow-up studies are needed to determine if anastrozole can lower the incidence of deaths due to breast cancer given the few deaths from the disease among the trial participants.

An Exciting Find

Better and longer protection, along with fewer and more tolerable side effects, should make anastrozole the "drug-of-choice" for post-menopausal women who are at a higher risk of developing breast cancer.

Cuzick said their results were "an exciting find" that "makes a strong case for anastrozole being the drug of choice for post-menopausal women at high risk of developing breast cancer." He also noted that tamoxifen could still be offered to the few women who experience significant side effects from the new drug.

The Mirror UK reports that anastrozole is not currently offered to all the women who may benefit from it because some doctors remain wary of the evidence of its long-term impact.

Both tamoxifen and anastrozole can be offered to women who are at an increased risk of breast cancer, according to Cancer Research chief clinician Charles Swanton, noting the importance of having choices for women.

"Up until now we only knew tamoxifen has long-lasting benefits, so it’s reassuring that this study looking specifically at anastrozole, which has fewer long term side-effects, gives better protection to women years after they stopped taking the drug," Swanton said, as per the Mirror UK.

"Doctors may still decide that tamoxifen is more appropriate for some women, but it’s great there are options."

Low Uptake

Considering that the drug is not given to all women, Cuzick said uptake on it "has really been quite low." Speaking to BBC, the lead author said only 10% of women are being prescribed with the drug but they believe that the number should be higher.

Side effects are what put off women from taking breast cancer-preventing drugs, specifically tamoxifen. In the UK, merely 15% of high-risk women in a survey said they were taking the drug as nearly 75% said they were concerned about potential side effects.

Swanton advised those who have questions about the effects of tamoxifen or anastrozole, or about their family and risk of developing the disease, to consult their doctor to help them work out the best medication for them.

Swanton advised those who have questions about the effects of tamoxifen or anastrozole, or about their family and risk of developing the disease, to consult their doctor to help them work out the best medication for them / Photo by: Robert Przybysz via Shutterstock