在乳房攝影前可能不需要停止荷爾蒙治療

作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　June 11, 2009 — 根據一項於6月2日發表在內科學誌的隨機分派研究結果，在乳房攝影前可能不需要停止荷爾蒙治療。
　　
　　西雅圖華盛頓大學健康研究團隊健康中心的Diana S.M. Buist醫師與其同事們寫到，沒有群眾為基礎的證據，部分臨床醫師建議短期暫停荷爾蒙治療，以改善乳房攝影品質。荷爾蒙治療增加乳房密度，而乳房密度較高與正在使用荷爾蒙治療的女性，乳房攝影篩檢異常的比例較高。
　　
　　這項研究的目的在於評估，對45至80歲女性而言，於乳房攝影之前短暫停止荷爾蒙治療1至2個月，可以降低另外再進行一次乳房攝影的機率。
　　
　　在2004年到2007年之間，於西華盛頓整合式健康計畫中1,704位45至80歲使用荷爾蒙治療的女性，在她們最近的一次乳房攝影篩檢（指標），或是定時接受篩檢（試驗）乳房攝影，或是仍在使用荷爾蒙治療，這些女性被分為三組。受試者以遮蔽隨機分派來分組，根據乳房密度與使用荷爾蒙治療種類、繼續接受荷爾蒙治療（共567位）、乳房攝影前停用一個月（共570位）、或是停用兩個月（共567位）。
　　
　　所有的乳房攝影由單一不知道分組的放射科醫師判讀。研究主要試驗終點為接受額外乳房攝影比例，次要試驗終點為指標與試驗乳房攝影之間的乳房密度差異（百分比與區域密度）。
　　
　　未停藥組的女性，額外接受乳房攝影的比例為542位中有61件（11.3%），停藥一個月組則是478位中有50件（12.3%），停藥兩個月組是451件中有44件（9.8%）。研究者們並未確認出任何短暫停藥與再次乳房攝影比例下降有關的關聯性。
　　
　　乳房密度百分比的變化，在未停藥組為0.1%、停藥一個月組為-0.9%、停藥兩個月組為-1.5%。區域密度也有相似的狀況與統計上顯著差異的下降。停止荷爾蒙治療的女性，停經症候群症狀顯著增加。
　　
　　研究作者們寫到，短暫停止使用荷爾蒙治療與乳房密度小幅改變有關，但並未影響再次接受攝影的機率。並沒有支持乳房攝影前暫停荷爾蒙治療的證據。
　　
　　這項研究的限制包括，參與率低（39%符合條件的女性），以及僅有單一位放射科醫師判讀結果。這項研究發現僅一般化至45~80歲使用荷爾蒙治療至少一年的女性。
　　
　　研究作者們的結論是，其研究結果顯示，短暫停止使用荷爾蒙治療會增加停經症候群。對預防或偵測乳癌，我們必須了解因為內生性暴露（例如奇偶性或是周期性改變）造成的乳房密度變化，以及外在性暴露（例如不同的荷爾蒙治療與劑量、tamoxifen、或是芳香酶抑制劑）可能因為被設計來降低乳房攝影乳房密度的介入，有差異性地受益。
　　
　　美國國防部與國家癌症機構贊助這項研究。研究作者們表示沒有相關資金上的往來。

Hormone Therapy May Not Need to Be Suspended Before Mammography

By Laurie Barclay, MD
Medscape Medical News

June 11, 2009 — Hormone therapy may not need to be suspended before mammography, according to the results of a randomized trial reported in the June 2 issue of the Annals of Internal Medicine.

"Without population-based evidence, some clinicians recommend short-term suspension of hormone therapy to improve the performance of mammography," write Diana S.M. Buist, PhD, MPH, from Group Health Center for Health Studies, University of Washington in Seattle, and colleagues. "Hormone therapy increases breast density, and abnormal screening mammograms are more common among women with denser breasts and among women using hormone therapy."

The goal of this study was to evaluate whether temporarily discontinuing hormone therapy for 1 to 2 months before screening mammography in women ages 45 to 80 years is associated with decreased recall for additional mammographic imaging.

From 2004 to 2007 at an integrated health plan in western Washington, 1704 women ages 45 to 80 years who used hormone therapy at their most recent screening (index) mammography, who were due for screening (study) mammography, and who were still using hormone therapy were assigned to 1 of 3 groups. Participants were allocated by block random assignment, based on breast density and type of hormone therapy, to continuation of hormone therapy (n = 567), to suspension for 1 month (n = 570), or to suspension for 2 months (n = 567) before study mammography.

All mammograms were read by a single radiologist blinded to group assignment. The main endpoint of the study was recall for additional mammographic imaging, and the secondary endpoint was change between the index and study mammograms in mammographic breast density (percentage and dense area).

For women in the no-suspension group, mammography recall rate was 61 (11.3%) of 542 vs 50 (12.3%) of 478 in the 1-month suspension group and 44 (9.8%) of 451 in the 2-month suspension group. The investigators did not identify any subgroups in which brief hormone therapy suspension was associated with a decreased rate of mammography recall.

Changes in percentage of breast density were 0.1% in the no-suspension group, –0.9% in the 1-month suspension group), and –1.5% in the 2-month suspension group. Similar orderly and statistically significant decreases were noted for dense area. Menopausal symptoms increased in women who suspended hormone therapy.

"Brief hormone therapy suspension was associated with small changes in breast density and did not affect recall rates," the study authors write. "No evidence supports short-term hormone therapy suspension before mammography."

Limitations of this study include low participation rate (39% of eligible women) and readings by a single expert radiologist. The findings are only generalizable to women aged 45 to 80 years who have used hormone therapy for at least 1 year.

"Our results also demonstrate a substantial negative effect on women from increased menopausal symptoms," the study authors conclude. "For breast cancer detection and prevention, we need to understand whether women whose breast density changes in response to endogenous exposures (such as parity or cyclical changes) and exogenous exposures (such as various hormone therapy types and doses, tamoxifen, or aromatase inhibitors) may benefit differentially from interventions designed to decrease mammographic breast density."

The US Department of Defense and the National Cancer Institute funded this study. The study authors have disclosed no relevant financial relationships.

Ann Intern Med. 2009;150:752-765.

可以降低另外再進行一次乳房攝影的機率。