缓解癌性疼痛新方法
From 自明知识
在一项34名癌症患者的研究中，称为冷冻消融的方法缓解了对其他治疗均无效的持续强烈疼痛。“这确实是剧烈的、持续性的疼痛，为此患者需要服用麻醉药物，只是为了熬过去”，研究员Matthew Callstrom 博士（明尼苏达州罗彻斯特梅奥诊所的放射科医师）说。据所有的患者讲，至少一些疼痛缓解了。所有患者的疼痛都能减低，而且一些患者甚至停止服用麻醉药品。 Callstrom在接受WebMD的采访时说，最重要的是这些饱受癌症痛苦患者的生活质量得到了改善。“患者说，平均起来，在本研究开始的时候，他们一半的生活饱受着肿瘤疼痛之扰。到24周之后，这个比例下降至10%，”他说。该研究发现发表在北美放射学年会上。
引导探针穿透皮肤
该微创技术包括经由患者皮肤上四分之一英寸的切口插入一些很小的探针（叫做cryoapplicators），使用超声或者CT成像引导这些探针进入肿瘤内。然后气体在探针内循环。当接触到探针的钢尖的时候，气体迅速冷却，并冻结邻近的区域。冷冻破坏了癌细胞、炎症细胞以及引起疼痛的小的感觉神经细胞。这项最新研究纳入了34名癌症患者，他们所患的癌症包括结肠直肠癌、肾癌、肺癌以及卵巢癌。所有患者都严重地患有已扩散到骨骼的攻击性癌症。
据Callstrom 称，每年大约200,000患癌症的美国人饱受因骨扩散所致的控制不佳的疼痛。在该研究开始的时候，在10分的疼痛评分尺度上，这些患者的疼痛评分平均为7.2分。4周后，疼痛得到显著减轻。该疗法似乎有持续效果：在接受该治疗操作的24周后，平均疼痛评分只有1.7分。在24周的研究过程中，许多患者死亡了，但那不是意外死亡，因为全部患者被认定为身患绝症。冷冻消融不是设计用来恢复健康或治愈癌症，而是用来减轻躯体痛苦的，Callstrom说。该研究工作由美国Endocare公司提供资金，该公司制造了此研究中使用的冷冻消融装置。
冷冻消融 vs 放射治疗
基于该研究结果，研究人员被授予国立癌症研究所的奖助金，用来引领一项进行冷冻消融术与放射治疗对比的全国性的研究，放射治疗是当前治疗已发生骨扩散的晚期癌症相关疼痛的金标准。布朗大学放射学教授，也进行冷冻消融研究的Damian Dupuy博士在接受WebMD采访时说，放射治疗或许是大多数患者的一个较好的选择。“癌症往往已经扩散到许多不同的部位。放射治疗能够立刻打击许多部位，但是如果采用冷冻消融，你可能就会到处插探针。患者将会在临终的时候看上去象一个针垫，”他说。 Dupuy讲，但是有占相当大比例的少数患者 -- 近乎25% -- 从这些患者身上可以证实冷冻消融是更好的选择。他说，“那就是为什么我们需要做这项研究的原因”。
Freezing the Pain of Cancerous Tumors
Cryoablation Offers Relief When All Else Fails
Nov. 27, 2007 (Chicago) -- Doctors are freezing the pain out of agonizing tumors.
In a study of 34 cancer patients, the method, called cryoablation, alleviated relentless pain that hadn't respond to all other treatments.
"This was really severe, persistent pain that required patients to take narcotics just to get through the day," says researcher Matthew Callstrom, MD, PhD, a radiologist at the Mayo Clinic in Rochester, Minn.
All reported at least some pain relief. All were able to cut back on, and in some cases even stop taking, narcotics.
Most importantly, Callstrom tells WebMD, was the improvement in their quality of life.
"Patients said, on average, that half their life was affected by pain at the start of the study. By 24 weeks later, it was down to 10%," he says.
The findings were presented at the annual meeting of the Radiological Society of North America.
Probes Guided Through Skin The minimally invasive technique involves inserting tiny probes called cryoapplicators through a quarter-inch cut in the patients' skin, using ultrasound or CT imaging to guide them into the tumor.
Gas is then circulated through the probes. When exposed to the probe's steel tip, the gas rapidly cools and freezes the area. Freezing destroys the cancer cells, inflammatory cells, and small sensory nerve cells that cause pain.
The new study involved 34 patients with a range of cancers including colorectal, kidney, lung, and ovarian. All were gravely ill with aggressive cancer that had spread to the bone.
According to Callstrom, about 200,000 Americans with cancer have poorly controlled pain due to bone spread each year.
At the start of the study, their pain score averaged 7.2 points on a 10-point scale. Four weeks later, pain was significantly reduced. The treatment appeared to have lasting effects: 24 weeks after undergoing the procedure, the average pain score was just 1.7 points.
A number of the patients died during the 24-week study, but that wasn't unexpected since all were considered terminally ill. Cryoablation is not designed to restore health or cure cancer, but to reduce physical suffering, Callstrom says.
The work was funded by Endocare Inc., which makes the cryoablation system used in the study.
Cryoablation vs. Radiation Based on the results, the researchers were awarded a grant from the National Cancer Institute to lead a nationwide study to pit cryoablation against radiation therapy, the current gold standard for treating pain associated with advanced cancer that has spread to the bone.
Damian Dupuy, MD, a professor of radiology at Brown University who has also studied cryoablation, tells WebMD that radiation is probably a better option for most patients.
"Often the cancer has spread to many different sites. Radiation can hit many sites at once, but if you do cryoablation, you'll have probes all over the place. The patient will end up looking like a pincushion," he says.
But there is a sizable minority -- nearly 25% -- for whom cryoablation may prove the better option, Dupuy says.
"That's why we need to do the study," he says.
|