点击显示 收起
August 1, 2007 — 新颖的光学技术在侦测胰脏癌方面出现令人鼓舞的结果，8月号的临床癌症研究刊登这项初步研究结果显示可侦测到早期与末期的胰脏腺癌。
伊利诺斯州埃文斯顿西北大学的Vadim Backman生物医学工程博士与其同事，在此研究中应用最近发展的两项互补式光学技术，四维弹性光散射光谱（4D-ELF）与低相干散射增强（LEBS）光谱，运用组织中特殊结构表现的波长、与散射角度的弹性光散射信号来解释这项研究。此项技术也可侦测到之前无法定量的纳米及微米架构的原位癌。
Backman博士向Medscape表示，目前没有任何方法能可靠地诊断胰脏癌，也没有影像或分子测试可以侦测到早期可治愈的胰脏癌。
他解释，胰脏癌主要来自于胰管，可以利用内视镜逆行性胆胰造影术检测胰腺癌，就如同结肠镜检查能侦测结肠癌一样；Backman博士表示，问题就在于当怀疑有胰脏疾病，包括内视镜检查、切片检查、或细针穿刺细胞学检查都有20%的案例会发生并发症的风险，也包括急性胰脏炎，因此内视镜逆行性胆胰造影术、及其他技术并不适合用来筛检胰脏疾病。
在一项试验研究中，Backman博士与同事以4D-ELF及LEBS光谱评估采样的组织，采检样本是19位胰脏癌患者十二指肠壶腹部的正常黏膜切片，与32位定期接受内视镜检查的健康受试者检体进行比较。
4D-ELF及LEBS讯号同时由相同的设备获得，分析是在采检的2小时内完成；研究者也分析从远端十二指肠黏膜及对照组9个受试者的胃及4个胰脏癌患者的检体去检验视野效应的空间程度。
Backman博士与其团队表示，由4D-ELF/LEBS而来的光散射特征，表现了结构的特性与光学性能或“指纹”，这些指纹提供组织光散射性质的深度敏感定量资讯，也在散射型态上有显著定性的差异；为了光散射特性的变化与组织定量的方法，他们也分析了一系列的光学标记。
【高灵敏度和特异性】
他们发现利用4D-ELF及 LEBS的定量光学标记可以鉴别出胰脏癌与健康对照组的差异，且具有95%的敏感度与91%的特异性；在诊断可切除的胰脏癌，其敏感度与特异性更高（分别为100 %与94%）。
Backman博士指出，我们的数据显示，例行的内视镜十二指肠黏膜光学分析即可侦测胰脏癌，而不需询问胰脏病史；如果能在大型临床研究获得证实，这项试验可以成为初步筛选或风险分层测试；若答案是肯定的，那更严格与潜在风险的介入将是合理的做法。
Backman博士补充道，此报告只显示藉由分析十二指肠组织可侦测胰脏癌的可行性，战略上要将此技术作为筛检方法取决于未来更大型研究的结果。
Backman博士表示，另一个可行性是筛检胰脏癌的高危险群，例如有家族史或抽烟者，这可以成为重点检查项目的一个部份，再次提醒大家，这只是一个早期研究，仍需要大型的试验加以确认。
这项研究由美国国家科学基金会（NSF）与国家卫生研究院（NIH）赞助。
Novel Optical Technology Shows Promise in Early Detection of Pancreatic Cancer
By Roxanne Nelson
Medscape Medical News
August 1, 2007 — Novel optical technology has shown promising results in detecting pancreatic cancer. Published in the August issue of Clinical Cancer Research, the results of this preliminary study found that both early- and advanced-stage pancreatic adenocarcinoma could be detected.
Vadim Backman, PhD, a professor of biomedical engineering at Northwestern University in Evanston, Illinois, and colleagues, recently developed the 2 complementary optical techniques that were used in the study. The 4-dimensional elastic light-scattering spectroscopy (4D-ELF) and low-coherence enhanced backscattering (LEBS) spectroscopy use the elastic light-scattering signals from tissue that exhibit characteristic structure-dependent signatures in wavelength and scattering angle, explain the researchers in their paper. They also allow for the previously unattainable quantitative assessment of nanoarchitecture and microarchitecture in situ.
"Currently, there is no methodology that can reliably diagnose pancreatic cancer," Dr. Backman told Medscape. "There are no imaging or molecular tests that are able to detect pancreatic cancer in an early, curable stage."
He explained that, given that the majority of pancreatic cancers originate from the pancreatic duct, it would be feasible to assume that endoscopic retrograde cholangiopancreatography (ERCP) is able to detect pancreatic carcinomas in the same manner that colonoscopy can detect colon cancers. "But the problem is that essentially any interrogation of the pancreas, including ERCP, biopsy, or fine needle biopsy, carries a very high risk of complications in about 20% of cases, including acute pancreatitis," he said. "This makes ERCP and other techniques that interrogate the pancreas not suitable for screening."
In a pilot study, Dr. Backman and colleagues evaluated tissue samples with 4D-ELF and LEBS spectroscopy. The specimens were obtained from periampullary duodenal biopsies that were taken from normal-appearing mucosa in 19 patients with pancreatic cancer. These were then compared with tissue from periampullary duodenal biopsies obtained from 32 healthy controls during routine endoscopic procedures.
The 4D-ELF and LEBS signals were obtained simultaneously using the same instrument, and the analyses were performed within 2 hours of the acquisition of the sample tissue. The researchers also analyzed biopsies that were taken from the distal duodenal mucosa and the stomach of 9 individuals in the control group and 4 pancreatic cancer patients to examine the spatial extent of the field effect.
According to Dr. Backman and his team, the light-scattering signatures derived from 4D-ELF/LEBS exhibit characteristic structure and optical property-dependent patterns or ''fingerprints.'' These fingerprints provide depth-sensitive quantitative information about the light-scattering properties of tissue and also show significant qualitative differences in scattering patterns. In order to characterize changes in light-scattering signatures and tissue structures in a quantitative manner, they also analyzed a series of optical markers.
High Sensitivity and Specificity
They found that the quantitative optical markers obtained from their 4D-ELF and LEBS were able to differentiate patients with pancreatic cancer from the healthy controls, with 95% sensitivity and 91% specificity. The sensitivity and specificity were even greater (100% and 94%, respectively) for differentiating pancreatic cancer patients with resectable tumors.
"Our data show that it may be possible to detect the presence of pancreatic cancer, without the need for interrogation of the pancreas, by optical analysis of duodenal mucosa that can be accessed by a routine upper endoscopy," said Dr. Backman." If proven in larger clinical studies, this test can become the initial screening or risk-stratification test. If positive, a more rigorous and potentially risky intervention will be justified."
The strategy for incorporating this technology into a screening program would depend on the outcome of future larger-scale studies, Dr. Backman added; this report only shows the feasibility of detecting the presence of pancreatic cancer by analysis of duodenal tissue.
"One possibility is to screen patients at a higher risk for pancreatic cancer, such as those with family history or who smoke," he said. "This can be a part of a focused screening program. Again, this is an early study and has to be validated in larger studies."
The National Science Foundation (NSF) and the National Institutes of Health (NIH) funded the study
Clin Cancer Res 2007;13:4392-4399.