comst053 2010-6-16 00:38
放射線治療並不能改善高齡初期乳癌患者存活
作者：Roxanne Nelson
出處：WebMD醫學新聞
May 26, 2010 — 一項新研究的結論是，輔助放射線治療可能不是高齡初期乳癌接受腫塊切除術的患者所必須的。70歲以上罹患初期乳癌接受腫塊切除術且使用tamoxifen的女性，可以安全地拋棄放射線治療，因為這顯然不會影響存活率、免於遠端轉移存活率、乳癌專一性存活率或是乳房保留機率。
在10年時，接受tamoxifen治療女性的乳癌專一性存活率為98%，接受tamoxifen與放射線治療女性則是96%。那些僅接受tamoxifen的女性，10年整體存活率為63%，加上放射線治療女性則是61%。
來自波士頓麻州綜合醫院外科部的Kevin S. Hughes醫師在美國臨床腫瘤醫學會（ASCO）2010年年會前的記者會上表示，我們發現放射線治療確實有部分乳癌再發率的好處，但那些好處是相對較小的。這項研究結果將會在6月7日發表。
他指出，加上放射線治療，可以進一步降低乳房內再發率大約6%，但是這對於保留乳房的最終能力並無影響、對於遠端轉移、乳癌整體存活率也沒有影響。
ASCO理事長Douglas W. Blayney醫師表示，這項研究結果確實證實了執業方式且可能潛在地改變執業方式。
Blayney醫師表示，從他與同事們的經驗，當她們了解效益不大時，許多這個族群的高齡女性經常選擇放棄放射線治療。他附帶表示，這些結果讓臨床醫師在支持我們的病患根據信念決定治療時的一些慰藉，且可能改變我們對病患所提出的建議。
【加上放射線治療並無存活上的好處】
目前這項研究是該項研究初步分析的後續追蹤，顯示在後續追蹤中位數達7.9年時，僅使用tamoxifen是tamoxifen加上放射線治療一個有效的替代選擇。這項新研究包括10.5年後的後續追蹤數據。
研究收納636位年齡在70歲以上，罹患第一期、淋巴結陰性、雌性激素受體（ER）陽性乳惡性腫瘤且已經接受腫塊切除女性。這些受試者被隨機分派接受tamoxifen加上放射線治療（共317位女性）或是僅使用tamoxifen（共319位女性）。我們的主要試驗終點是局部再發、因再發進行乳房切除、遠端轉移所需時間、及乳癌專一性死亡率與所有原因死亡率。
Hughes醫師解釋，放射線治療只有在一個終點有很小的好處。相較於那些僅接受tamoxifen者，接受tamoxifen加上放射線治療的病患同側乳癌再發下降6%。他表示，基本上，我們要對319位女性進行放射線治療才能預防20件乳房內再發，這是相當小的好處。
除此之外，兩個族群間，其他的試驗終點並無顯著差異（P>0.05）。10年時不用接受乳房切除的機率，僅使用tamoxifen為96%，使用tamoxifen加上放射線治療則是98%；免於遠端轉移的機率分別為95%與93%。
兩組之間10年乳癌專一性存活率是相似的：僅使用tamoxifen為98%，tamoxifen加上放射線治療為96%。整體存活率分別為63%與61%。
【避免放射線治療是可行的】
Hughes醫師指出，研究中43%死亡，但這是個高齡族群，且幾乎沒有任何死亡事件肇因於乳癌。他解釋，只有放射線組的12位婦女、與tamoxifen組的8位死於乳癌，所以絕大多數是死於其他原因。
這些發現顯示，超過10年的後續追蹤，腫塊切除、僅加上抗雌性激素治療對這個族群來說是個適當的治療。現在，問題變得對這些70歲以上，罹患初期、ER陽性腫瘤，tamoxifen是否足夠。這代表與病患討論這個議題，但是我認為這個族群避免放射線治療是非常可行的。
這項研究由國家癌症機構贊助。作者們表示沒有相關資金上的往來。
Radiation Does Not Improve Survival in Elderly Early-Stage Breast Cancer Patients
By Roxanne Nelson
Medscape Medical News
May 26, 2010 — Adjuvant radiation therapy might not be necessary for older women with early-stage breast cancer who undergo lumpectomy. Women 70 years or older with early-stage disease who have a lumpectomy and also receive tamoxifen can safely forego radiation therapy because it does not appear to affect survival, distant disease-free survival, breast-cancer-specific survival, or breast conservation, a new study concludes.
At 10 years, the breast-cancer-specific survival for women who received tamoxifen was 98%, compared with 96% for those who received tamoxifen and radiation. Those who received tamoxifen only had a 10-year overall survival of 63%, compared with 61% for women who also received radiation therapy.
"We found that radiotherapy did have some benefit in terms of in-breast recurrence, but those benefits were relatively small," said Kevin S. Hughes, MD, from the Department of Surgery at Massachusetts General Hospital in Boston, at a press briefing held in advance of the American Society of Clinical Oncology (ASCO) 2010 Annual Meeting. The study will be presented on June?7.
"You can get about a 6% reduction in in-breast recurrence with the addition of radiation, but it has no impact on the ultimate ability to preserve the breast, no impact on distant metastases, no impact on breast-cancer-specific morality, and no impact on overall survival," he said.
The results are?.?.?. certainly practice affirming and may be potentially practice changing.
Douglas W. Blayney, MD, president of ASCO, said the results of this study are "certainly practice affirming and may be potentially practice changing."
From his own experience and the experiences of his colleagues, Dr. Blayney noted that many older women in this group often elect to forgo radiation when they understand the small benefit. These results "give us some comfort as physicians in supporting that decision on our patients' behalf, and that may change the recommendation we make to our patients," he added.
No Survival Benefit With Added Radiation Therapy
The current study is a follow up to an earlier analysis of this trial, which showed that after a median follow-up of 7.9 years, tamoxifen alone was an effective alternative to tamoxifen and radiation. This new analysis includes follow-up data after 10.5 years.
The study involved 636 women who were 70 years of age or older with clinical stage?I, node-negative, estrogen-receptor (ER)-positive breast carcinoma who had undergone lumpectomy. They were randomized to receive tamoxifen plus radiation therapy (n?= 317 women) or tamoxifen alone (n?= 319 women). The primary end points of the study were time to locoregional recurrence, mastectomy for recurrence, distant metastases, breast-cancer-specific mortality, and all-cause mortality.
There was a small benefit for radiation therapy in only 1 of the end points, Dr. Hughes explained. Patients who received tamoxifen plus radiation had an absolute 6% reduction in ipsilateral breast tumor recurrence, compared with those who received tamoxifen alone. "Essentially, we would have to irradiate 319 women to prevent 20 in-breast recurrences, which is a fairly small benefit," he said.
Otherwise, the remaining end points did not differ between the 2 cohorts (P?> .05). The probability of being free from mastectomy at 10 years was 96% for tamoxifen only and 98% for tamoxifen plus radiation; being free from distant metastases was 95% and 93%, respectively.
The 10-year breast-cancer-specific survival was also similar between the 2 groups: 98% for tamoxifen only and 96% for the tamoxifen plus radiation. Overall survival was 63% and 61%, respectively.
Feasible to Avoid Radiation
Dr. Hughes pointed out that 43% of the patients in this study have died, but this was an older population and almost none of the deaths were due to breast cancer. "Only 12 women died in the radiation group died from breast cancer and only 8 in the tamoxifen group, so the majority died of other causes," he explained.
These findings demonstrate that after more than 10 years of follow-up, lumpectomy with antiestrogen therapy alone can be an appropriate treatment option for this population. "The question now becomes whether tamoxifen is enough treatment for women aged 70 and older with these small-stage, ER-positive tumors," said Dr. Hughes. "This means discussing it with patients, but I think avoiding radiation in this group is very feasible."
The study was funded by the National Cancer Institute. The authors have disclosed no relevant financial relationships.
American Society of Clinical Oncology (ASCO) 2010 Annual Meeting: Abstract?507. To be presented June?7, 2010.