Abstract 4333: Optical diagnostic system with Raman spectroscopy for gastric cancer

Abstract Background. Raman spectroscopy (RAS) is one of the available optical techniques, and the Raman spectrum for each molecule and tissue is characteristic and specific. We reported the usefulness of a Raman spectrum as a novel diagnostic modality for gastric cancer by using the biopsied specimens on 100th Annual Meeting. We present here the advanced data of RAS by using resected specimen of gastric cancers to clarify the possibility of endoscopic application of RAS for the real-time diagnosis of the gastric cancer. Methods. Without any pretreatment, the fresh specimens were measured with a near-infrared multichannel Raman spectroscopic system with an excitation wavelength of 1064nm, and Raman spectra specific for the specimens were obtained. A principal component analysis (PCA) was performed to distinguish gastric cancer and non-neoplastic tissue, and a discriminant analysis was used to evaluate the accuracy of the gastric cancer diagnosis. We reported sensitivity of RAS was 66%, specificity was 73%, and accuracy was 70%, respectively, by using 251 fresh biopsy specimens of gastric carcinoma and non-neoplastic mucosa. In the present study, we examined the Raman spectrum of the resected specimen of gastric cancers to clarify the clinical usefulness of RAS during endoscopy, because Raman spectrum during endoscopy is obtained from whole layer of stomach. Raman spectrum from mucosal side were obtained at 213 points (81 cancer points and 132 non-cancer points) by using 10 resected specimen (12 lesions). Results. Raman spectrum in the cancer points clearly differed from those for on-neoplastic points, especially at around 1644cm−1, as well as those observed in biopsied specimens. Analysis with PCA demonstrated that sensitivity was 72%, specificity was 78%, and accuracy was 76%. Interestingly, in the advanced gastric cancers, specificity was increased to 92% resulting that accuracy was also increased to 88%. Furthermore, the comparison between cancer points and non-cancer points without atrophy demonstrated that sensitivity was 89%, specificity was 86%, and accuracy was 88%. Conclusions. RAS with a 1064-nm excitation wavelength is useful for gastric cancer diagnosis. Raman diagnostic system may be improved according to the development of both systemic instruments and analytical methods. And in the near future, RAS makes possible real-time diagnosis of gastric cancer during endoscopy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4333.