《柳葉刀》乳房癌治療研究顯示：保乳術後接受放射療法可以降低複發率，挽救生命

    乳癌保乳術後接受放射療法可以使乳腺癌複發的風險減半

(記者薩迪·懷特洛克斯) [英國《每日郵報》網站10月21日報道]

    科學家說，放射線療法大大降低接受過乳房腫瘤切除術的乳腺癌患者腫瘤複發的風險。

    牛津大學的研究人員發現，術後放療能使乳腺癌複發的幾率減少50%。

    研究人員在10年期間，對1萬多名女性的數據進行了評估。這是同類研究中最為深入的研究之一。

    研究結果表明，放療能減少癌症向身體其他部分擴散的可能性，是許多人挽救生命的重要手段。

    醫生往往在手術後對病人實施利用高能X光的放射線療法，殺死沒有被切除的癌細胞。

    此項研究的負責人薩拉·達比教授說：“一些人一直懷疑，是否所有患者都有必要在保乳術後接受放療。我們的研究結果證實，對幾組女性而言，放療是挽救生命的重要手段。”

    放療經過謹慎的設計，以確保盡可能多地殺死癌細胞，同時保護健康細胞。放療次數取決於腫瘤的位置、腫瘤大小和類型以及患者的總體健康狀況。

    此項研究涉及的所有女性以前都有通過乳房腫瘤切除術就可以去除的小腫瘤。

    在曆時10年的研究期間，患者的病情受到監控，科學家將接受過和沒有接受過放療的女性的狀況進行了對比。

    達比教授指出，雖然自從研究開始以來，乳腺癌的治療方法一直在發展，但了解放療的長期益處將有助於指導今後的治療。    她還說：“隻要有可能，患乳腺癌的女性都接受手術，要麽是乳房切除術(切除整個乳房)，要麽是保乳手術(隻切除部分乳房)。”

    達比教授說：“目前的原則是，接受過保乳手術的所有女性都應進行放療。對於接受了乳房切除術的女性而言，如果腫瘤已擴散至腋下淋巴結但沒有擴散至其他地方，放療是有必要的。”

    此項研究結果本周刊登在《柳葉刀》醫學期刊上。托馬斯·巴克霍爾茲教授評價說：“放療降低乳腺癌複發的風險，更重要的是，放療提高總體生存幾率。”

    他說：“放療使乳腺癌複發的可能性減少50%，這或許是治療乳腺癌最有效的方法。”

Breast Cancer Study: Radiation Slashes Recurrence, Saves Lives

Radiation therapy following breast conserving surgery reduced the rate of disease recurrence by half, a large meta-analysis found.

In trials of more than 10,000 women with breast cancer, the use of radiation therapy decreased the risk of recurrence within 10 years from 35% to 19.3%, according to investigators from the Early Breast Cancer Trialists' Collaborative Group (EBCTCG).

That represented an absolute reduction of 15.7% (95% CI 13.7 to 17.7, 2P<0.00001), the investigators reported online in The Lancet.

Because the possibility that microscopic remnants of tumor may remain with breast conserving surgery, radiation has often been used with the aim of preventing recurrences and metastases.

However, the long-term outcomes of these efforts have not been fully chronicled, so the EBCTCG have been following their large cohort of clinical trial participants and periodically updating their outcomes data.

The current report included 17 trials that began before 2000, six of which evaluated the use of radiation therapy after lumpectomy in 4,398 low- and high-risk women.

Four of the trials examined the results of radiotherapy after quadrantectomy or sector resection in 2,399 women. The remaining seven compared radiotherapy following lumpectomy in 4,004 women considered to be at low risk.

This analysis found that not only did radiotherapy reduce the rate of 10-year recurrences, but also decreased the 15-year mortality risk by 3.8% (95% CI 1.6 to 6, 2P=0.00005), the investigators reported.

Women who had radiation therapy after their surgery also had half the annual rate of a first recurrence compared with those not given radiotherapy (RR 0.52, 95% CI 0.48 to 0.56), with the greatest benefit seen during year one (RR 0.31, 95% CI 0.26 to 0.37).

The annual death rate was reduced with the use of radiation therapy by about one-sixth (RR 0.82, 95% CI 0.75 to 0.90).

The investigators also looked at differences depending on whether the women had lymph node positive or negative disease.

Among those who were lymph node negative and had radiotherapy, the annual recurrence rate during the first 10 years fell by about half (RR 0.46, 95% CI 0.41 to 0.51).

This decreased the 10-year recurrence risk to 15.6% from 31%, which represented an absolute risk reduction of 15.4% (95% CI 13.2 to 17.6, 2P<0.00001), the investigators found.

These lymph node negative women also had a decrease in mortality over 15 years, to 17.2% from 20.5%, which was an absolute risk reduction of 3.3% (95% CI 0.8 to 5.8, 2P=0.005).

Women who were lymph node positive and received radiation therapy experienced a five-fold decrease in recurrences during the first year, from 26% to 5.1% (RR 0.20, 95% CI 0.14 to 0.29), according to the investigators.

Mortality also was reduced in lymph node positive women who had radiotherapy (RR 0.79, 95% CI 0.65 to 0.95, 2P=0.01).

Further analyses of patient subgroups determined that absolute reduction in recurrences was significantly associated with age (2P=0.0002), tumor grade (2P<0.00001), and estrogen receptor status and use of tamoxifen (2P=0.003).

Finally, the investigators calculated that among the entire cohort, by year 15 one death was prevented for every four recurrences prevented at year 10.

They noted that the risk reduction was less in the most recent trials with the wider use of tamoxifen.

"However, even for women with [lymph node negative] disease in the recent low-risk trials, the predicted absolute 10-year recurrence reduction with radiotherapy exceeded 10% in most women and exceeded 20% in some women," they observed.

In a comment accompanying the meta-analysis, Thomas A. Buchholz, MD, of the University of Texas MD Anderson Cancer Center in Houston, observed, "These results confirm that radiation is effective in eradication of much of the microscopic locoregional disease that might still be present after surgery."

"The data reinforce the important role that radiotherapy has in management of breast cancer, and the fact that the benefits of radiation are complementary to the advances in both surgery and systemic treatment is particularly rewarding," Buchholz wrote.

論文摘要：
Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10 801 women in 17 randomised trials

Early Breast Cancer Trialists' Collaborative Group (EBCTCG)‡

The Lancet, Early Online Publication, 20 October 2011 DOI: 10.1016/S0140-6736(11)61296-8.

Background
After breast-conserving surgery, radiotherapy reduces recurrence and breast cancer death, but it may do so more for some groups of women than for others. We describe the absolute magnitude of these reductions according to various prognostic and other patient characteristics, and relate the absolute reduction in 15-year risk of breast cancer death to the absolute reduction in 10-year recurrence risk.

Methods
We undertook a meta-analysis of individual patient data for 10 801 women in 17 randomised trials of radiotherapy versus no radiotherapy after breast-conserving surgery, 8337 of whom had pathologically confirmed node-negative (pN0) or node-positive (pN+) disease.

Findings
Overall, radiotherapy reduced the 10-year risk of any (ie, locoregional or distant) first recurrence from 35·0% to 19·3% (absolute reduction 15·7%, 95% CI 13·7—17·7, 2p<0·00001) and reduced the 15-year risk of breast cancer death from 25·2% to 21·4% (absolute reduction 3·8%, 1·6—6·0, 2p=0·00005). In women with pN0 disease (n=7287), radiotherapy reduced these risks from 31·0% to 15·6% (absolute recurrence reduction 15·4%, 13·2—17·6, 2p<0·00001) and from 20·5% to 17·2% (absolute mortality reduction 3·3%, 0·8—5·8, 2p=0·005), respectively. In these women with pN0 disease, the absolute recurrence reduction varied according to age, grade, oestrogen-receptor status, tamoxifen use, and extent of surgery, and these characteristics were used to predict large (≥20%), intermediate (10—19%), or lower (<10%) absolute reductions in the 10-year recurrence risk. Absolute reductions in 15-year risk of breast cancer death in these three prediction categories were 7·8% (95% CI 3·1—12·5), 1·1% (—2·0 to 4·2), and 0·1% (—7·5 to 7·7) respectively (trend in absolute mortality reduction 2p=0·03). In the few women with pN+ disease (n=1050), radiotherapy reduced the 10-year recurrence risk from 63·7% to 42·5% (absolute reduction 21·2%, 95% CI 14·5—27·9, 2p<0·00001) and the 15-year risk of breast cancer death from 51·3% to 42·8% (absolute reduction 8·5%, 1·8—15·2, 2p=0·01). Overall, about one breast cancer death was avoided by year 15 for every four recurrences avoided by year 10, and the mortality reduction did not differ significantly from this overall relationship in any of the three prediction categories for pN0 disease or for pN+ disease.

Interpretation
After breast-conserving surgery, radiotherapy to the conserved breast halves the rate at which the disease recurs and reduces the breast cancer death rate by about a sixth. These proportional benefits vary little between different groups of women. By contrast, the absolute benefits from radiotherapy vary substantially according to the characteristics of the patient and they can be predicted at the time when treatment decisions need to be made.

Funding
Cancer Research UK, British Heart Foundation, and UK Medical Research Council.