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HRT May Protect Against Smoking-Associated Cancers

Laurie Barclay, MD

Sept. 9, 2003 — Hormone replacement therapy (HRT) may protect against
smoking-associated cancers, according to the results of a study
published in the September issue of Obstetrics & Gynecology.

"We hypothesized that HRT use would favorably affect those epithelial
tissues for which smoking is a carcinogen," write H. Olsson, MD, PhD,
and colleagues from University Hospital in Lund, Sweden. "Specifically,
HRT would maintain epithelial thickness and integrity, thus
counteracting tumor development."

From 1990 to 1992, the investigators conducted baseline interviews in
29,508 Swedish women aged 25 to 65 years with no history of cancer. When
follow-up ended on Dec. 31, 1999, 1,145 malignancies had been diagnosed.
Women who went through natural menopause and had ever used HRT had no
increased incidence of cancer overall.

Women who smoked and who used HRT long-term had a decreased incidence of
smoking-related cancers, including cancer of the oral cavity, pharynx,
hypopharynx, larynx, esophagus, lung, cervix, and bladder (standardized
incidence ratio, 0.24; 95% confidence interval [CI]. 0.08 - 0.76). The
type of HRT used and number of cigarettes smoked did not affect this
finding.

HRT appeared to protect against colon cancer in both smokers and
nonsmokers. Nonsmokers who used HRT had an increased incidence of
endometrial cancer.

Because of study limitations, including relatively small sample size and
limited follow-up, the authors recommend confirmation in future studies.

"The purpose of this report is not to advocate that women should smoke,"
the authors write. "We recommend that women use HRT as appropriate by
the evolving standard of care and refrain from smoking."

The Swedish Cancer Society, Lund University, and the Gunnar Nillson
Foundation helped support this study.

Obstet Gynecol. 2003;102:565-570

Reviewed by Gary D. Vogin, MD

http://www.medscape.com/viewarticle/461088?mpid=18644