Hormone replacement therapy (HRT) once seemed so promising for alleviating the most troubling symptoms of menopause but prolonged study into their overall effect on a woman’s health continues to reveal hidden dangers in the therapy itself.  Of latest concern is that women who develop lung cancer after taking HRT pills that combine estrogen and progestin are at increased risk of dying from the cancer than are women who have not taken HRT.  Women who smoke cigarettes are at particular risk.

Dr. Richard Schilsky, president of the American Society of Clinical Oncology, urges ‘great caution’ when undergoing HRT.  Schilsky, also a University of Chicago cancer specialist, was responding to a presentation by Dr. Rowan Chlebowski, Harbor-UCLA Medical Center, Los Angeles, at the oncology society’s annual meeting in Florida this week.

Chlebowski’s findings are based on long-term study of a federal study, the Women’s Health Initiative, which involved 16,608 women, some of them taking a popular estrogen-progestin combo pill (Prempro) and others taking a placebo.  Although the study was discontinued in 2002 after an alarming number of women taking Prempro developed breast cancer, follow-up studies, such as Chlebowski’s, continue.

According to Chlebowski’s research, women developed lung cancer at about the same rate in both groups but the group of women taking HRT for five years, with two years of follow-up care, were 60% more likely to die from their cancers than women taking the placebos.  Overall, 106 cases of lung cancer have been diagnosed in the women in the entire study.  Of those taking Prempro, 46% have died from lung cancer but only 27% in the placebo group have died.

Chlebowski warns that women who smoke cigarettes should not seek HRT and smokers currently undergoing HRT should discontinue the treatment.  He urges careful thought, especially for women who smoke.

Dr. Joseph Camardo, of Wyeth Pharmaceuticals, the company that manufactures the HRT pills used in the study, says HRT isn’t used today the same way it was used when the federal study began and that the incidence of lung cancer fatalities may be different under contemporary conditions.  On average, women were 63 years old when they began HRT use in the study but the average woman using HRT today is more likely to be between 51 and 54 years of age.  Another difference is duration of treatment; in the original study, women took HRT for five years or longer but today’s woman usually uses the therapy for only about two years.

The Chlebowski study was based on the combination HRT, using both estrogen and progestin.  Still under investigation are HRT medications that contain only estrogen.

Lung cancer kills more people around the world than any other form of cancer.  In 2008, the US saw at least 215,000 new cases and almost 162,000 deaths were attributed to it.