修改過的放射線治療可能改善肺癌患者預後

作者：Zosia Chustecka  
出處：WebMD醫學新聞

　　May 18, 2010 — 一項收納2279位患者的綜合分析結果顯示，相較於傳統放射線治療，加速分次或是高分次放射線治療，可能提供非小細胞肺癌（NSCLC）與小細胞肺癌（SCLC）患者存活上的好處。
　　
　　這項發現在最近的第2屆瑞士日瓦亞歐洲肺癌會議，由Cecile Le Pechoux醫師與其來自法國維勒瑞夫Gustave-Roussy機構的同事們報告。
　　
　　Le Pechoux醫師解釋，相較於傳統療程，病患在加速分次或高分次放射線治療療程中於短時間內接受更頻繁的放射線。目前為止，個別隨機分派研究比較這兩種方法的結果不一。他預測，現在，這項最新的綜合分析結果已經證實，這項修改過的放射線治療有存活上的好處，且將成為該研究領域一個再次興起的興趣。
　　
　　當聯繫尋求評論時，來自華盛頓西雅圖瑞典癌症機構的Howard (Jack) West醫師同意這樣的看法。
　　
　　他表示，這並不是最強的證據，但這確實顯示高分次放射線療程可能與整體存活率提升有關。這附帶了過去雖然是非常有限的證據，高分次放射線治療可以轉化為臨床預後改善確切的支持。
　　
　　West醫師向Medscape腫瘤學表示，這個方法在NSCLC患者身上確實沒有被廣泛採用，且在SCLC患者身上使用率也不高。對我而言，這項綜合分析結果代表，肺癌相關研究學者應仔細且全面性地探索高分次放射線治療，尤其是較新的放射線治療技術以及顯影技術的進步，讓我們可以更精準地投予放射線，而發生禁止性的毒性風險較低，這在高分次放射線治療上是個很重要的擔憂。
　　
　　【臨床好處很小】
　　這項綜合分析共收納1594位NSCLC患者（來自8項臨床研究），相較於傳統放射線治療，加速分次或是高分次放射線治療，可以改善整體預後（危險比值[HR]為0.87；P=0.009），5年時絕對風險降低了3%。
　　
　　Le Pechoux醫師表示，我們發現的臨床預後是很小的，但是與其他以非小細胞肺癌進行的綜合分析好處相當。
　　
　　研究者們解釋，不同研究之間並無顯著異源性，且不同亞群患者並沒有對修改過的放射線治療特別有好處或是效果較差。
　　
　　他們表示，修改過後的放射線治療顯著降低死於肺癌的事件（HR為0.89；P=0.03），顯然也可以降低非肺癌死亡事件數，雖然並未達到統計上顯著差異（HR為0.79；P=0.18）。
　　
　　然而，這對於免於惡化存活率並無好處（HR為0.94；P=0.23）。
　　
　　有兩項研究共收納685位SCLC患者，在這個族群仍有觀察到相似的存活好處（HR為0.87；P=0.08）。研究者們報告，雖然因為統計檢力不足未達到統計上顯著差異。
　　
　　該團隊表示，如同預期的，相較於傳統放射線治療，修改過的放射線治療增加了急性食道毒性風險（NSCLC患者的HR為2.11，SCLC患者的HR為2.46；P<0.001）。但是並未增加急性血液、肺部、或是心臟毒性。
　　
　　研究者們表示沒有相關資金上的往來。


Modified Radiotherapy May Improve Survival in Lung Cancer

By Zosia Chustecka
Medscape Medical News

May 18, 2010 — Accelerated or hyperfractionated radiotherapy regimens might offer a survival benefit over conventional radiotherapy in patients with nonsmall cell lung cancer (NSCLC) and small-cell lung cancer (SCLC), concludes a new meta-analysis of 2279 patients.

The finding was reported at the recent 2nd European Lung Cancer Conference in Geneva, Switzerland, by Cecile Le?Pechoux, MD, and colleagues from the Institut Gustave-Roussy, in Villejuif, France.

With accelerated or hyperfractionated regimens, patients receive radiation more frequently and over a shorter period of time than with conventional regimens. To date, individual randomized trials comparing these 2 approaches have produced contradictory results, Dr. Le?Pechoux explained. Now that this latest meta-analysis has shown survival benefits from the modified approach, there will be a "renewed interest in this research field," he predicted.

Howard (Jack) West, MD, from the Swedish Cancer Institute in Seattle, Washington, concurred when approached for comment.

This is not "the strongest evidence," he said, but it does suggest that hyperfractionation might contribute to overall survival. It adds to previous — although very limited — evidence that "is certainly supportive that hyperfractionation could translate to improvements in clinical outcomes."

"This approach is certainly not widely practiced in NSCLC, and is underutilized in SCLC," Dr. West told Medscape Oncology. "To me, the results of this meta-analysis suggest that the lung cancer community should explore hyperfractionation carefully and systematically, especially because newer radiation techniques and improved imagining allows us to deliver radiation more precisely, and therefore with lower risk for prohibitive toxicity, which has been a significant concern with hyperfractionation strategies."

Clinical Benefit Is Small

The meta-analysis involved 1594 patients with NSCLC (from 8 trials). Accelerated or hyperfractional radiotherapy improved overall survival, compared with conventional radiotherapy (hazard ratio [HR], 0.87; P?= .009), resulting in an absolute benefit of 3% at 5 years.

"The clinical benefit we found was small but comparable to the benefit found in other meta-analyses concerning nonsmall-cell lung cancer," said Dr. Le?Pechoux.

There was no heterogeneity among the trials, and no subgroup of patients was found to benefit more or less from modified radiotherapy, the researchers explain.

The modified radiotherapy approach significantly reduced deaths from lung cancer (HR, 0.89; P?= .03), and also appeared to reduce nonlung-cancer deaths, although this was not significant (HR, 0.79; P?= .18), they note.

However, there was no benefit for progression-free survival (HR, 0.94; P?= .23).

There were also 2 trials involving 685 patients with SCLC. Similar survival benefit was seen in this group (HR, 0.87; P?= .08), although this was not statistically significant because of a lack of power, the researchers report.

As expected, modified radiotherapy increased the risk for acute esophageal toxicity, compared with conventional radiotherapy (HR, 2.11 in NSCLC and HR, 2.46 in SCLC; P?< .001), the team notes. But there was no increase in acute hematologic, pulmonary, or cardiac toxicity, they add.

The researchers have disclosed no relevant financial relationships.

2nd European Lung Cancer Conference: Abstract?1850. Presented April?30, 2010.