越來越多乳癌病患選擇乳房切除術

作者：Roxanne Nelson  
出處：WebMD醫學新聞

　　August 1, 2009 — 根據在梅約診所進行的手術分析，在一段時間的利用率偏低之後，越來越多婦女選擇接受乳房切除術，以治療早期乳癌。
　　
　　雖然此一增加趨勢的原因尚不清楚，研究者推測，或許與術前使用磁振共振造影(MRI)有關。接受乳房MRI的婦女比那些未進行MRI者更可能會選擇接受乳房切除術(54% vs 36%)。
　　
　　此研究發現線上發表於7月27日的臨床腫瘤期刊(Journal of Clinical Oncology)，也發表於2008年美國臨床腫瘤協會年會中，當時由Medscape Oncology進行報導。
　　
　　梅約診所的乳房切除術比率在1997年至2003年間呈現下降趨勢，但是在2004年開始出現上揚。乳房切除術比率在2003至2006年間，從31%上升到43%，相當於1997年時的比率。
　　
　　國家健康共識發展小組研究中心在1990年的共識聲明中，支持以乳房保留手術作為早期乳癌婦女的優先方法。在該聲明發表之後，第1期疾病者選擇乳房保留手術(乳房腫瘤切除之後進行放射線治療)的比率，從1989年的35%增加到1995年的60%，第2期疾病者，選擇乳房保留手術的比率則是從1989年的19%增加到1995年的29%。作者指出，有關乳房切除術比率的資料在過去10年間則有限。
　　
　　【有哪些變化？】
　　根據編輯評論，最明顯的問題是：「有哪些變化？」除了目前的研究之外，其他研究也顯示在同樣期間內乳房切除術比率增加。
　　
　　紐約市Sloan-Kettering紀念癌症中心的Monica Morrow醫師以及波士頓達那法柏癌症研究中心的Jay R. Harris醫師在他們的評論中指出，檢測BRCA1和BRCA2等突變的警覺增加，且經常被引述為乳房切除術使用比率增加的因素。
　　
　　不過，他們寫道，這些突變只佔所有乳癌病患的5%至10%。一等親有乳癌之婦女的比率並未隨著時間增加，但乳房切除術比率則是逐漸增加。因此，無法解釋在本研究與其他研究所發現的效應。
　　
　　編輯解釋，乳房MRI在診斷上的使用增加，用以排除同側乳房之多病灶乳癌，編輯指出，在最近的一篇後設分析中，MRI在16%的新診斷乳癌病患發現其他的腫瘤病灶。這使得8%至33%病患的治療改變，大多造成非得進行乳房切除術不可 (J Clin Oncol. 2008;26:3248-3258)。
　　
　　在這個由梅約診所腫瘤內科醫師Matthew P. Goetz所領導的研究中，他們試圖評估MRI造成乳房切除比率增加的角色。在他們的回溯分析中，探討了在1997至2006年間，於梅約診所進行乳房手術的5,405名病患。
　　
　　結果顯示，乳房手術比率每年都有顯著變化。先是漸漸下降，從1997年的45%降低到2003年的31% (P< .0001)，之後則是逐漸上升，從2004年的37%上升到2006年的43%。同時，使用MRI的比率也增加，從2003年的10%增加到2006年的23%(P< .0001)。
　　
　　編輯指出，本研究的主要發現是，接受MRI的病患比那些未接受MRI者更可能接受乳房切除術。多變項模式中，MRI以及手術年份都是乳房切除術的獨立預測因子。
　　
　　即使接受MRI的婦女比較可能進行乳房切除術，但未進行乳房MRI婦女的乳房切除術比率卻是增加最大。研究作者寫道，在接受和未接受MRI者之中，乳房切除術比率在2003至2006年間都呈現增加，而接受MRI者接受手術的比率並未顯著增加，反而是未接受MRI者的手術比率有顯著增加(2003年的29%相較於2006年的41%)。
　　
　　【需要更好的溝通】
　　編輯指出，這些有關使用MRI與增加乳房切除術比率之關聯的發現有點令人困擾，僅代表著謎團的一部份，因為，未接受MRI者的乳房切除術比率也增加。他們寫道，在美國，許多地方的病患要求醫師進行乳房切除術，甚至是雙側乳房切除，即便告知如此治療並不會改善預後亦然。
　　
　　他們也指出，歐洲並沒有出現這種乳房切除術增加的傾向。
　　
　　越來越多證據認為，是由癌症的生物學確定局部復發風險，而非某一種特定的局部治療使然。編輯寫道，顯然的，我們並未將此告訴病患，他們依舊相信選擇乳房切除術可以降低癌症復發風險。當病患面對新癌症診斷時的壓力時，我們必須更努力和他們溝通這些複雜的治療選項。
　　
　　研究作者和編輯同意，需要新研究評估，這些選用手術上的變化是否可以改變病患的生活品質和/或滿意度。
　　
　　作者和編輯都宣告沒有相關財務關係。
　　
　　J Clin Oncol. 線上發表於2009年7月27日。

Breast Cancer Patients Increasingly Opting for Mastectomy

By Roxanne Nelson
Medscape Medical News

August 1, 2009 — After a steady decline, women have increasingly been opting to undergo mastectomy to treat early-stage breast cancer at the Mayo Clinic in Rochester, Minnesota, according to an analysis of surgeries conducted there.

Although the reasons for this increase remain unclear, researchers speculate that it might be related to the use of magnetic resonance imaging (MRI) prior to surgery. Women who had a breast MRI were more likely to have a mastectomy than those who did not (54% vs 36%).

The findings, published online July 27 in the Journal of Clinical Oncology, were presented at the American Society of Clinical Oncology 2008 Annual Meeting, and were reported by Medscape Oncology at that time.

Mastectomy rates at the Mayo Clinic declined from 1997 to 2003, but in 2004, there was a reversal of this trend. The rate of mastectomies rose from 31% to 43% between 2003 and 2006, which was equivalent to rates seen in 1997.

In a 1990 consensus statement, the National Institutes of Health Consensus Development Panel supported breast-conservation surgery as the preferred method of primary surgical therapy for women with early-stage breast cancer. The percentage of those opting to undergo breast-conservation therapy (lumpectomy followed by radiation) increased after the release of this statement, from 35% in 1989 to 60% in 1995 for stage?I disease and from 19% in 1989 to 29% in 1995 for stage?II disease. But data regarding the rates of mastectomy during the past 10 years are limited, the authors note.

What Has Changed?

"The obvious question is: What has changed?" according to an accompanying editorial. In addition to the current study, other studies have shown rising rates of mastectomy during the same period.

In their commentary, Monica Morrow, MD, from Memorial Sloan-Kettering Cancer Center in New York City, and Jay R. Harris, MD, from the Dana-Farber Cancer Institute in Boston, Massachusetts, point out that an increased awareness of and testing for BRCA1 and BRCA2 mutations are frequently cited as factors that have increased the use of mastectomy.

However, these mutations occur in only 5% to 10% of all breast cancer patients, they write. Although the proportion of women with a first-degree relative with breast cancer did not increase over time, the rate of mastectomy did. Therefore, it is an unlikely explanation for a large part of the effect seen in this series and in other studies.

Breast MRI is being increasingly used at the time of diagnosis to exclude the presence of multifocal or multicentric breast cancer in the ipsilateral breast, explain the editorialists, who point to a recent meta-analysis in which MRI identified additional tumor foci in 16% of newly diagnosed breast cancer patients. This led to a change in treatment for 8% to 33% of patients, and most commonly resulted in mastectomy that would otherwise not have been performed (J Clin Oncol. 2008;26:3248-3258).

In the current study, lead author Matthew P. Goetz, MD, medical oncologist at the Mayo Clinic, and colleagues attempted to evaluate the role of MRI in the increased rate of mastectomy. In their retrospective analysis, they identified 5405 patients who underwent breast surgery at the Mayo Clinic between 1997 and 2006.

The results showed that mastectomy rates varied significantly according to year of surgery. Mastectomy rates gradually, decreased from 45% in 1997 to 31% in 2003 (P?< .0001), but then rose from 37% in 2004 to 43% in 2006. Concurrently, the use of MRI increased, from 10% in 2003 to 23% in 2006 (P?< .0001).

"The key finding of this study is that patients who underwent MRI were more likely to undergo mastectomy than those who did not undergo MRI," the editorialists note. "In a multivariable model, both MRI and year of surgery were independent predictors of mastectomy."

Even though women who underwent MRI were more likely to have a mastectomy, the largest increase in the mastectomy rate occurred in women who did not have a breast MRI. Although mastectomy rates increased from 2003 to 2006 in patients who had and had not undergone an MRI, the study authors write, this increase was not statistically significant in women who had undergone an MRI. But the increase was significant among those who had not undergone an MRI (29% in 2003 vs 41% in 2006).

Better Communication Needed

The editorialists note that although these findings about the use of MRI and increased mastectomy rates are "troubling," they represent only 1 piece of the puzzle, since increasing rates of mastectomy were also observed in patients who did not undergo MRI. "In many parts of the United States, patients are pushing their surgeons for mastectomy, even bilateral mastectomy, despite being told that such treatment will not improve prognosis," they write. They also point out that this trend toward mastectomy does not seem to be occurring in Europe.

An increasing body of evidence suggests that the biology of the cancer rather than a specific type of local therapy largely determines the risk for local recurrence. "Clearly, we are not communicating this to our patients if they continue to choose mastectomy in the belief that it is a reasonable choice for decreasing risk of cancer recurrence," write the editorialists. "More work is also clearly needed on how to effectively communicate complex treatment choices to women facing the stress of a new cancer diagnosis."

The study authors and editorialists agree that new studies are needed to evaluate whether these changes in surgical management lead to improvements in quality of life and/or patient satisfaction.

The authors and editorialists have disclosed no relevant financial relationships.

J Clin Oncol. Published online before print July 27, 2009.