Breast cancer risk from menopause hormones may last decades

SAN ANTONIO — Women who use certain types of hormones after menopause still have an increased risk of developing breast cancer nearly two decades after they stop taking the pills, long-term results from a big federal study suggest.

Although the risk is very small, doctors say a new generation of women entering menopause now may not be aware of landmark findings from 2002 that tied higher breast cancer rates to hormone pills combining estrogen and progestin.

“The message is probably not clear” that even short-term use may have lasting effects, said Dr. Rowan Chlebowski of Harbor-UCLA Medical Center in Torrance, California. He discussed the new results Friday at the San Antonio Breast Cancer Symposium.

The results are from the Women’s Health Initiative, a federally funded study that tested pills that doctors long thought would help prevent heart disease, bone loss and other problems in women after menopause. More than 16,000 women ages 50 to 70 were given combination hormone or dummy pills for five to six years.

The main part of the study was stopped in 2002 when researchers surprisingly saw more heart problems and breast cancers among hormone users. Women were advised to stop treatment but doctors have continued to study them and have information on about two-thirds.

With roughly 19 years of followup, 572 breast cancers have occurred in women on hormones versus 431 among those on dummy pills. That worked out to a 29% greater risk of developing the disease for hormone takers.

Still, it was a difference of just 141 cases over many years, so women with severe hot flashes and other menopause symptoms may decide that the benefits of the pills outweigh their risks, doctors say. The advice remains to use the lowest possible dose for the shortest time.

Why might hormones raise breast risk?

“The hormones are stimulating the cells to grow” and it can take many years for a tumour to form and be detected, said Dr. C. Kent Osborne, a Baylor College of Medicine breast cancer expert.

Women are prescribed hormones in combination because taking estrogen alone raises the risk of uterine cancer. However, one-quarter of women over 50 no longer have a uterus and can take estrogen alone for menopause symptoms.

So the same study tested estrogen alone versus dummy pills in more than 10,000 such women, and the conclusion was opposite what was seen with combination hormones. Women on estrogen alone for seven years had a 23% lower risk of developing breast cancer up to 19 years later. There were 231 cases among them versus 289 in the placebo group.

These results contradict what some observational studies have found, though, and doctors do not recommend any hormone use to try to prevent disease because of the murky picture of risks and benefits.

The federal study only tested hormone pills; getting hormones through a patch or a vaginal ring may not carry the same risks or benefits.

The results are another reason that hormone users should follow guidelines to get regular mammograms to check for cancer, said Dr. Jennifer Litton, a breast specialist at MD Anderson Cancer Center in Houston.

“Continuing to screen appropriately remains important,” she said.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Canada’s basketball community mourns Kobe Bryant after helicopter crash

In his 40 years in basketball, nothing Chuck Swirksy has seen compared… Continue reading

Canadian officials say more coronavirus cases expected but risk ‘remains low’

The first Canadian patient diagnosed with coronavirus began showing signs of illness… Continue reading

Quebec police divers find final sunk snowmobile amid search for missing tourists

ST-HENRI-DE-TAILLON, Que. — Divers with Quebec’s provincial police say they have located… Continue reading

Personal spending a party matter, Conservative Leader Andrew Scheer says

OTTAWA — Conservative Leader Andrew Scheer declined Saturday to shed any light… Continue reading

Human remains found in burned Alberta hotel after ice thaws enough to permit search

WETASKIWIN, Alta. — Police in Alberta say that after a week of… Continue reading

Fashion Fridays: The basics you need for your body type

Kim XO, helps to keep you looking good on Fashion Fridays on the Black Press Media Network

Your community calendar

Feb. 1 A Jump Rope Competition will be held at the Abbey… Continue reading

Bryant’s 13-year-old daughter killed in crash

A source familiar with the helicopter crash that killed Kobe Bryant says… Continue reading

Ex-NBA star Kobe Bryant dies in helicopter crash

LOS ANGELES — Kobe Bryant, the 18-time NBA All-Star who won five… Continue reading

Canucks, Oilers, Flames primed for mad dash in congested Pacific Division

Matthew Tkachuk doesn’t need to be reminded of the Pacific Division’s razor-thin… Continue reading

Canada’s Drury wins silver and Thompson takes bronze at ski-cross World Cup

IDRE FJALL, Sweden — Toronto’s Kevin Drury won silver in the men’s… Continue reading

Officials track passengers on flight with coronavirus patient

Public health officials were working Sunday to track down some of the… Continue reading

Get coronavirus information from credible sources: public health officials

TORONTO — Even before Canada’s first coronavirus case was announced in Toronto… Continue reading

Deputy prime minister asks Opposition not to delay new NAFTA

OTTAWA — Deputy Prime Minister Chrystia Freeland is asking the Opposition parties… Continue reading

Most Read