作者：Roxanne Nelson
出處：WebMD醫學新聞
March 11, 2010 — 根據發表於腫瘤外科協會(SSO)年度癌症研討會的新資料，有些只有擴散到1個淋巴結的早期乳癌婦女，可能無法從乳房切除術後的放射線治療獲得幫助。
德州大學安德森癌症中心的研究者發現，手術、輔助化療、和/或荷爾蒙治療之後，陽性淋巴結數量為0-3的T1和T2期乳癌患者，局部復發率風險相當低。
追蹤期間中位數為94個月(95%信心區間[CI]為88- 94)，追蹤期間內，所有研究對象之局部復發率只有2.13% (n= 22人)。無淋巴結轉移以及有1處淋巴結轉移者之間，復發率也無統計上的差異(3.3% vs 2.1%)。
資深作者、安德森癌症中心腫瘤外科訓練計畫主任Henry Kuerer博士解釋，放射線治療適用於乳房腫瘤切除後，因為它可減少復發率，但是有關乳房切除術之後(進行放射線治療)的資料有限。
【資料可能已經過時】
他在訪問中向Medscape Oncology表示，我們有長期資料，但是是舊資料，這些舊資料來自1960至1980年代的隨機研究，而當時這些婦女的局部復發率高，所以放射線治療有幫助。
Kuerer博士指出，在2005年，對1960至1980年代的試驗進行統合分析顯示，相較於沒有放射線治療者，乳房切除術後進行放射線治療的婦女，其局部復發率減少66%，該分析也顯示，放射線治療相關的存活利益有限。
這些發現促成臨床實務有一點改變，國家綜合癌症網絡在2007年改變指引，建議淋巴結轉移數量為1-3的第1和第2期乳癌，在乳房切除術後積極考慮進行放射線治療。
Kuerer博士表示，這些研究中，整體的5年和10年復發率範圍從20%到25%，高出目前所觀察的數據許多，在我們自己的臨床實務中則沒有這樣。
Kuerer博士解釋，在進行這些試驗的這幾十年中，乳癌的診斷和治療有許多改變，我們有了更好的篩檢方法、更好的偵測與手術技術，而且我們現在有研究當時所沒有的新治療方式，病理學也有改善，可以進行更廣泛的淋巴結檢查。
乳房切除術後進行放射線治療，可有效降低淋巴結擴散數量為4個以上之病患的局部復發機率，她們的復發風險超過15%。這類案例進行放射線治療的利益顯然大於風險，而對存活有幫助。
Kuerer博士解釋，但是，淋巴結轉移數量只有1-3個的早期乳癌病患使用放射線治療，已經成為癌症學界的熱門討論議題。
【低復發率】
研究目標是確認當代的局部復發率，以便更能釐清這類乳癌病患在乳房切除術後進行放射線治療的可能幫助，Kuerer博士與他的研究團隊進行了一個回溯研究，評估1997-2002年間，在安德森癌症中心接受乳房切除術的1022名第1或2期乳癌病患的臨床因素與病理因素。
這組病患的年紀中位數為55歲，79%有T1期腫瘤、21%是T2期腫瘤，多數病患(74%)沒有淋巴結轉移，不過有26%有1- 3個陽性淋巴結，研究中，沒有病患在乳房切除術後接受放射線治療或新輔助治療，77%接受輔助化療和/或荷爾蒙治療。
【淋巴結狀態與局部復發(LRR)】
陽性淋巴結數量 | 人數(%) | 5 年 LRR | 10 年 LRR |
0 | 753 (74) | 1.2% | 2.4% |
1 | 180 (18) | 2.4% | 3.2% |
2 | 69 (7) | 3.1% | 6.7% |
3 | 21 (2) | N/A | N/A |
有3個陽性淋巴結的研究對象人數太少而無法確認相關比率；40歲以下病患、有淋巴結轉移的T2期腫瘤、雌激素受體陰性腫瘤等，發生局部復發的機會則顯著較高(P< .01)。
Kuerer博士表示，我認為我們的研究對於如何治療有1個陽性淋巴結的早期乳癌婦女將有所影響，不過，他提醒，必須依照個別病患的情況進行治療決策。
紐約市Sloan-Kettering紀念癌症中心外科乳房疾病服務小組主任Monica Morrow醫師表示，不認為目前的實務就這樣改變。
主持SSO研討會全員會議的Morrow醫師表示，研究中所提的是一個重要問題：「以目前有系統且高品質的手術進行乳房切除術後的婦女，局部復發率是多少？」，不過，該研究無法作為排除放射線治療的證據，因為這些病患都經過篩選。
她向Medscape Oncology表示，在這段期間，實際上有更多病患接受治療，接受了放射線治療或新輔助化療、或者兩種都有，我們沒有任何的相關資訊可以用來與未接受放射線治療者進行比較、有多少病患也不得而知，因此，應促成其他更多的廣泛研究，但是與改變實務無關。
Kuerer博士贊同需要更多研究，同時也指出，國際型隨機SUPREMO試驗目前正在招募病患，該試驗的目的在於評估有立即局部復發風險、1-3個淋巴結轉移婦女，乳房切除術後進行胸壁放射線治療的影響。
他表示，不過，可能還需要10年才能獲得結果。
腫瘤外科協會(SSO)年度癌症研討會：摘要47。發表於2010年3月6日。
Is Postmastectomy Radiation Necessary for All Breast Cancer Patients?
By Roxanne Nelson
Medscape Medical News
March 11, 2010 — Some women with early-stage breast cancer that has spread to only 1 lymph node might not derive a benefit from postmastectomy radiation, according to new data presented during the plenary session at the Society of Surgical Oncology (SSO) Annual Cancer Symposium in St. Louis, Missouri.
Researchers from the University of Texas M.D. Anderson Cancer Center in Houston found that after surgery, adjuvant chemotherapy, and/or hormonal therapy, the risk for local regional recurrence rates were extremely low for patients with T1 and T2 breast cancer with 0 to 3 positive lymph nodes.
At a median follow-up of 94 months (95% confidence interval [CI], 88 to 94), local regional recurrence occurred in only 2.13% (n?= 22) of the total number of patients in the study. There was also no statistical difference in the recurrence rates between patients with 1 lymph node metastasis and those with no nodal involvement (3.3% vs 2.1%).
Radiation is indicated for women after a lumpectomy because it reduces the recurrence rate, but the data are less clear after mastectomy, explained senior author Henry Kuerer, MD, PhD. professor and training program director in M.D. Anderson's Department of Surgical Oncology.
Data Could Be Outdated
"We have long-term data, but they are old data," he told Medscape Oncology in an interview. "They are from randomized studies that were conducted in the 1960s to 1980s, and the rates of local regional recurrence were high in these women. A benefit was seen with radiation."
Dr. Kuerer pointed out that in 2005, a meta-analysis of trials conducted in the 1960s to 1980s showed that there was a 66% reduction in locoregional recurrence in women who received postmastectomy radiation, compared with no radiation. The analysis also showed a small survival benefit associated with radiation therapy.
These findings led to a shift in clinical practice, and the National Comprehensive Cancer Network altered their guidelines in 2007 to suggest that stage?I and II breast cancer patients with 1 to 3 lymph node metastases "strongly consider" radiation after mastectomy.
The overall 5- and 10-year recurrence rates in those studies ranged from 20% to 25%, which are much higher than what is currently observed, said Dr. Kuerer. "We have not seen that in our own clinical practice."
We have better screening, better detection, better surgical techniques.
In the decades since those studies were conducted, Dr. Kuerer explained, much has changed in the treatment and diagnosis of breast cancer. "We have better screening, better detection, better surgical techniques, and we now have therapies that didn't exist when these early studies were done," he said. "Pathology has also improved, and more extensive examination of lymph nodes is now conducted."
Radiotherapy after mastectomy is effective at decreasing the chances of local regional recurrence in patients with lymph node spread in more than 4 nodes, and where the risk for recurrence is greater than 15%. "The benefit of radiation therapy in this case clearly outweighs the risk, and can offer a survival advantage," he said.
But the use of radiation in patients with early-stage breast cancer with only 1 to 3 positive nodes has been a "hot topic of debate" within the cancer community, Dr. Kuerer explained.
Low Recurrence Rates
The goal of this study was to determine the present-day rates of local regional recurrence to better gauge the potential benefit of postmastectomy radiation in this particular subpopulation of breast cancer patients. Dr. Kuerer and his colleagues conducted a retrospective study in which they evaluated the clinical and pathological factors of 1022 stage?I or II breast cancer patients who received a mastectomy at M.D. Anderson between 1997 and 2002.
The median patient age was 55 years and, within this group, 79% had T1 and 21% had T2 tumors. The majority of patients (74%) had no lymph node metastasis, but 26% had 1 to 3 positive nodes. None of the patients in the study received postmastectomy radiation therapy or neoadjuvant therapy, and 77% received adjuvant chemotherapy and/or hormonal therapy.
Node Status and Rates of Local Regional Recurrence (LRR) Number of
Positive Nodes | n (%) | 5-Year LRR | 10-Year LRR |
| 0 | 753 (74) | 1.2% | 2.4% |
| 1 | 180 (18) | 2.4% | 3.2% |
| 2 | 69 (7) | 3.1% | 6.7% |
| 3 | 21 (2) | N/A | N/A |
There were too few patients in the study with 3 positive nodes to determine rates. Patients who were younger than 40 years, who had T2 tumors with nodal metastasis, and who had estrogen-receptor negative tumors had significantly higher chances of local regional recurrence (P?< .01).
"I think that our study should have an impact on how women with early-stage disease and 1 positive lymph node are treated," said Dr. Kuerer, although he cautioned that treatment decisions must always be based on the individual patient.
Monica Morrow, MD, chief of the breast service in the Department of Surgery at Memorial Sloan-Kettering Cancer Center in New York City, doesn't believe that current practice should change just yet.
"The question asked in this study — what is the rate of local recurrence after mastectomy in patients receiving modern systemic therapy and high-quality surgery — is an important one," said Dr. Morrow, who moderated the plenary session at the SSO symposium. However, "this study cannot be used as evidence that radiation therapy can be eliminated, because this was a very selected group of patients."
This study should stimulate other more inclusive studies, but should not be regarded as practice-changing.
She told Medscape Oncology that there were many more patients who received treatment during the same time period, and who received radiation therapy and neoadjuvant chemotherapy, or both. "We don't have any information on how the group who didn't get radiation therapy compares or what percentage of patients they were," she explained. "So this study should stimulate other more inclusive studies, but should not be regarded as practice-changing."
Dr. Kuerer agreed that more studies are needed, and pointed to the international randomized SUPREMO trial, which is currently enrolling patients. The trial is designed to evaluate the role of chest-wall radiation therapy after mastectomy in women who are at intermediate risk for locoregional recurrence, with 1 to 3 involved lymph nodes.
"However," he said, "it may be a decade before we have that information."
Society of Surgical Oncology's Annual Cancer Symposium: Abstract?47. Presented March 6, 2010.
