懷念睿寶貝 Memory for Ray baby

資料來源:http://city.udn.com/53230/1996425?tpno=0&cate_no=59377
作者：Caroline Cassels 
出處：WebMD醫學新聞

　　November 24, 2006 — 第一個檢驗兒童癌症倖存者晚期發生中風風險的研究顯示，成功治癒腦瘤或急性白血病，這兩種兒童最常見癌症的兒童，晚期發生中風的機率較高。
　　位於達拉斯的德州大學西南醫學中心的研究者表示，罹患腦瘤兒童發生中風的機率為3.4%，但是接受顱內放射線療法（CRT）與化學療法的病患，中風機率上升到6.5%；而罹患白血病的兒童，中風機率為0.8%，其兄弟姐妹發生中風機率為0.2%。
　　主要研究者Daniel Bowers醫師在一項聲明中表示，許多人認為，你已經脫離癌症5年，你已經被治癒了，你可以好好地過接下來的生活，但是這些病患突然發生癌症與其治療所帶來的併發症。
　　
　　這項試驗結果發表於11月20日的臨床癌症期刊(Journal of Clinical Oncology)。
　　
　　【癌症治療所帶來的影響】
　　根據研究者表示，該試驗有三個目的：
　　* 為了估計被診斷白血病與腦部腫瘤5年後存活者發生中風的機率（晚期發生中風）
　　* 比較白血病與腦部腫瘤存活者及其兄弟姐妹得到晚期中風的機率
　　* 為了評估特定治療方式與晚期中風之間的關係
　　
　　透過兒童癌症存活者研究（CCSS）的數據，研究者針對一群大型且不同族群的癌症倖存者，分析其因為癌症治療而發生晚期中風的情形，共收納了4,828位白血病及1,871位腦瘤倖存者；除此之外，同時評估隨機採樣之3,846位癌症倖存者兄弟姐妹的中風發生率。
　　整體而言，37位白血病與63位腦瘤倖存者發生晚期中風，定義為發生於癌症診斷5年之後；白血病倖存者發生晚期中風機率為每10萬人每年57.9次，而腦瘤倖存者為每10萬人每年267.6次。
　　相較之下，這些癌症倖存者之兄弟姐妹發生中風的機率為每10萬人每年8.0次。
　　當研究者根據癌症病患所接受的治療分類進行分析，他們發現接受超過30葛雷以上顱內放射線療法兒童發生晚期中風機率較高。
　　
　　【CRT劑量反應關係】
　　此外，作者表示放射線療法劑量與中風機率之間有劑量反應關係，接受50葛雷以上放射線療法的倖存者，相較於接受30至49葛雷病患，其發生中風風險較高；相對的，低劑量的CRT，劑量自10至29葛雷，相較於未接受CRT治療，並不會增加中風風險。
　　然而，作者指出，未接受CRT的白血病與腦瘤倖存者，相較於其血緣關係兄弟姐妹，發生晚期中風仍然是顯著地較高。
　　根據Bowers博士表示，目前有希望減少使用放射線療法的趨勢，為了要降低與放射線療法有關的學習障礙；Bowers博士指出，這樣的倡議對於這群病患發生中風是否會有影響是很有趣的。
　　作者表示，這項試驗結果支持降低白血病與腦瘤治療療程放射線療法劑量的努力。
 
Stroke Risk Increased in Pediatric Cancer Survivors

By Caroline Cassels
Medscape Medical News

November 24, 2006 — The first study to examine late-occurring stroke risk in pediatric cancer survivors has found that children who have been successfully treated for brain tumors or acute lymphoblastic leukemia — the 2 most common childhood cancers — are at significantly increased risk of stroke in later life.

Researchers from University of Texas Southwestern Medical Center at Dallas, Texas, report that among children with brain tumors the stroke rate was 3.4%, but among patients treated with both cranial radiotherapy (CRT) and chemotherapy, the rate was as high as 6.5%. Among children with leukemia, the stroke rate was 0.8%; among their siblings the rate was 0.2%.

"Many people think, 'You're 5 years out from your cancer, you must be cured, and you can get on with the rest of your life.' But these patients suddenly develop a new complication of the cancer and its treatments," said principal investigator Daniel Bowers, MD, in a statement.

The study was published in the November 20 issue of the Journal of Clinical Oncology.

Impact of Cancer Treatment

According to the investigators, the study had 3 aims:

To estimate the incidence rate of stroke among leukemia and brain-tumor survivors 5 years or more after the diagnosis of cancer (late-occurring stroke)

To compare the rate of late-occurring stroke between leukemia and brain-tumor survivors and their siblings

To assess the association of specific treatments of late-occurring stroke.
Using data from the Childhood Cancer Survivor Study (CCSS), investigators analyzed stroke as a late effect of cancer treatment in a large and diverse cohort of cancer survivors, which included 4828 leukemia survivors and 1871 brain-tumor survivors. In addition, the occurrence of stroke was assessed in a random sample of 3846 cancer survivor siblings.

In total, 37 leukemia and 63 brain-tumor survivors had a late-occurring stroke, defined as a stroke that occurred 5 years or more after cancer diagnosis. The rate of late-occurring stroke for leukemia and brain-tumor survivors was 57.9 per 100,000 person-years and 267.6 per 100,000 person-years, respectively.

In comparison, the sibling group had a rate of stroke of 8.0 per 100,00 person-years.

When researchers analyzed the cohort according to the type of cancer treatment individuals received, they found an increased risk of late-occurring stroke, particularly in children treated with cranial radiotherapy at dose greater than 30 Gy.

CRT Dose Response

In addition, the authors report that there was a dose-response relationship between radiation-therapy dose and risk for stroke. "Survivors treated with CRT greater than 50 Gy had a significantly greater risk for stroke in comparison with those treated with 30 to 49 Gy," they write.

In contrast, lower-dose CRT, ranging from 10 to 29 Gy, was not associated with an increased risk, compared with no CRT.

However, the authors note that among both leukemia and brain-tumor survivors who did not receive CRT, "the risk of late-occurring stroke remained significantly increased, albeit modestly, compared with the sibling comparison group."

According to Dr. Bowers, there is an ongoing trend to try to minimize the use of radiation therapy, a move designed to lessen the learning problems associated with radiation therapy.

Dr. Bowers said it would be interesting to determine whether this initiative would also have an impact on the occurrence of stroke in this patient population.

This study, the authors write, "justifies efforts to continue to reduce radiation doses among both leukemia and brain-tumor treatment regimens whenever practical."

J Clin Oncol. 2006;24:5277-5282.