Breast Cancer and Hormone Replacement

Postmenopausal women who are recent, long-term users of hormone replacement therapy (HRT) have an elevated risk of invasive breast cancer.

HRT use may be particularly related to lobular tumours.

"In this nested, control study, we found an elevated risk of invasive breast cancer among postmenopausal women who were long-term, recent users of oral estrogen, either alone or in combination with progestin," United States researchers say.

"When we divided breast cancer cases into lobular and non-lobular (primarily ductal) cancers, we found somewhat divergent patterns associated with HRT.

"Association with HRT was considerably stronger for lobular breast cancer, with an approximately three-fold increased risk associated with longer duration of HRT and a four-fold risk for current use of combination therapy."

Investigators from the Fred Hutchinson cancer Centre and the University of Washington in Seattle comment: "Two prior studies have observed a two- to three-fold increased risk of lobular breast cancer associated with current combination therapy, and we found similarly large risks of lobular cancer associated with current combination therapy and longer duration of all formulations of HRT.

"A true increase in the risk of lobular breast cancer could have implications for screening, because lobular carcinomas are relatively more difficult to palpate and more difficult to diagnose by mammography.

"However, until more is known about the costs and benefits of different screening modalities for women using HRT, it would be premature to use our results as a basis for modifying early detection activity in them."

Their nested, case-control study included postmenopausal women enrolled in the Group Health Cooperative of Puget Sound. Participants were aged 50 to 74 years.

Researchers studied 705 cases of primary invasive breast cancer diagnosed between July 1990 and December 1995. They compared HRT use among case participants and 692 randomly selected, age-matched controls.

"Incidence of breast cancer, all histologic types combined, was increased by 60 percent to 85 percent in recent long-term users of HRT, whether estrogen alone or estrogen plus progestin," they report.

"Longer use of HRT and current use of combination therapy were associated with increased risk of lobular breast cancer.

"Long-term HRT use was associated with a 50 percent increase in non-lobular cancer."

The investigators point out, "If our results are correct, then non-users of HRT would have an incidence rate of ductal cancer of about 230 per 100,000 women per year, whereas women with five years of HRT use would have a rate of 349 per 100,000 women per year.

"Similarly, a three-fold risk of lobular cancer associated with HRT use would translate into an incidence of lobular cancer among non-HRT users of 23 per 100,000 women per year and 70 per 100,000 women per year among women with five years of recent HRT use.

"Thus, a woman with long-term HRT use would still be five times more likely to develop ductal rather than lobular breast cancer."

JAMA, 2002; 287: 734-741. "Hormone Replacement Therapy in Relation to Breast Cancer"

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	Hormone Replacement Raises Breast Cancer Risk In Postmenopausal Women A DGReview of :"Hormone Replacement Therapy in Relation to Breast Cancer" Journal of the American Medical Association (JAMA) 02/13/2002 By Elda Hauschildt Postmenopausal women who are recent, long-term users of hormone replacement therapy (HRT) have an elevated risk of invasive breast cancer. HRT use may be particularly related to lobular tumours. "In this nested, control study, we found an elevated risk of invasive breast cancer among postmenopausal women who were long-term, recent users of oral estrogen, either alone or in combination with progestin," United States researchers say. "When we divided breast cancer cases into lobular and non-lobular (primarily ductal) cancers, we found somewhat divergent patterns associated with HRT. "Association with HRT was considerably stronger for lobular breast cancer, with an approximately three-fold increased risk associated with longer duration of HRT and a four-fold risk for current use of combination therapy." Investigators from the Fred Hutchinson cancer Centre and the University of Washington in Seattle comment: "Two prior studies have observed a two- to three-fold increased risk of lobular breast cancer associated with current combination therapy, and we found similarly large risks of lobular cancer associated with current combination therapy and longer duration of all formulations of HRT. "A true increase in the risk of lobular breast cancer could have implications for screening, because lobular carcinomas are relatively more difficult to palpate and more difficult to diagnose by mammography. "However, until more is known about the costs and benefits of different screening modalities for women using HRT, it would be premature to use our results as a basis for modifying early detection activity in them." Their nested, case-control study included postmenopausal women enrolled in the Group Health Cooperative of Puget Sound. Participants were aged 50 to 74 years. Researchers studied 705 cases of primary invasive breast cancer diagnosed between July 1990 and December 1995. They compared HRT use among case participants and 692 randomly selected, age-matched controls. "Incidence of breast cancer, all histologic types combined, was increased by 60 percent to 85 percent in recent long-term users of HRT, whether estrogen alone or estrogen plus progestin," they report. "Longer use of HRT and current use of combination therapy were associated with increased risk of lobular breast cancer. "Long-term HRT use was associated with a 50 percent increase in non-lobular cancer." The investigators point out, "If our results are correct, then non-users of HRT would have an incidence rate of ductal cancer of about 230 per 100,000 women per year, whereas women with five years of HRT use would have a rate of 349 per 100,000 women per year. "Similarly, a three-fold risk of lobular cancer associated with HRT use would translate into an incidence of lobular cancer among non-HRT users of 23 per 100,000 women per year and 70 per 100,000 women per year among women with five years of recent HRT use. "Thus, a woman with long-term HRT use would still be five times more likely to develop ductal rather than lobular breast cancer." JAMA, 2002; 287: 734-741. "Hormone Replacement Therapy in Relation to Breast Cancer" Back

Hormone Replacement Raises Breast Cancer Risk In Postmenopausal Women