11-Year WHI Data Show Increase in More Advanced Breast Cancers

With median of 11 years of follow-up now in hand, investigators from the landmark Women Health Initiative (WHI) confirm that estrogen-plus-progestin hormone therapy is associated with greater breast cancer incidence than placebo. In short, they now say that the effect is long-term.

The new follow-up data are published in the October 20 issue of theJournal of the American Medical Association.

The data also provide other insights — that the cancers of combined hormone therapy users are more commonly node-positive than those of placebo users, and that breast cancer mortality seems to be increased with hormone therapy.

These data and others "dictate caution in the current approach to the use of hormone therapy," according to an editorial by Peter Bach, MD, which accompanies the study. Dr. Bach is from the Memorial Sloan-Kettering Cancer Center in New York City.

Dr. Bach says that this current approach, which employs hormone therapy for "brief periods" to relieve menopausal symptoms, has not had its safety proven in "rigorous clinical trials."

Clinicians cannot present patients with a risk/benefit analysis of short-term hormone therapy because no such data exist, he points out; the current WHI provides no information on short-term use.

Caution is especially advised for clinicians, says Dr. Bach, "because one of the lessons from the WHI is that physicians are ill-equipped to anticipate the effect of hormone therapy on long-term health."

However, the WHI authors seem concerned about longer-term use of combined hormone therapy — not short-term use.

They write that the "use of combined hormone therapy — other than short-term therapy in women with climacteric symptoms not ameliorated by other therapies — seems unwarranted."

Pfizer, which bought Wyeth in 2009 and with it Prempro combination hormone therapy, issued a statement as the media embargo on the WHI data was lifted. "We stand behind the current, science-based guidance in Prempro's label, which advises doctors to prescribe the medicine at the 'lowest effective dose and for the shortest duration consistent with treatment goals and risks for the individual woman'," the company stated.