Clinical validity of our color-imaging histo-diagnosis for cancer

We devised a color-imaging diagnosis for cancer, photodynamic histo-diagnosis (PDHD), with which we could clearly discriminate between cancer lesions and normal tissues. In an attempt to check the accuracy, we reexamined the PDHD method using two different types of colon tumors surgically harvested. The two specimens were treated according to our own procedures to microscopically observe reddish-pink fluorescence specifically emitted at cancer lesions. After which, such samples were modified to routine hematoxylin and eosin (HE) sections. Normal portion of the colon served as the control. To evaluate the diagnostic accuracy, we compared our PDHD findings with that of the HE sections. The two colonic samples emitted reddish-pink fluorescence by the PDHD method, which suggested that they were cancer lesions. While, diagnosis with the HE sections revealed one was “cancer in adenoma” and the other was “adenoma with no signs of cancer”. This result suggested all was not cancer that emitted reddish fluorescence with our PDHD. Introduction Clinical photodynamic diagnosis (PDD) and photodynamic therapy (PDT) have been often carried out in urological fields and neuro surgeries [1-4]. In PDD and PDT, aminolevulinic acid (ALA) is mainly used as a photosensitizer [5]. Based on the ALA-PDD theory, we took its rationale into our microscopic diagnostic manner as photodynamic histo-diagnosis (PDHD) and photodynamic cyto-diagnosis (PDCD) [6]. Using the novel method, we could visually discriminate a cancer cell from pathologically uncertain specimens in our previous study [6]. In this paper, we described further results of the PDHD to reconsider on its accuracy comparing with routine method with HE sections. Materials and methods Materials and methods have been already published [6]. Two different types of tumors which had grown at the colon of one patient were subjected to clinical specimens. After colectomy, each lesion was immediately treated for PDHD to detect the fluorescence. Then, the same samples were transformed to routine HE sections. We microscopically compared the PDHD findings with that of HE sections to evaluate diagnostic accuracy of our own PDHD. The HE sections were examined by one pathologist who was blinded to the PDHD. Results The two specimens treated with the PDHD method emitted reddish-pink fluorescence, by which we interpreted them as cancer. The normal sample showed no fluorescence (Figure 1). The HE sections once treated with PDHD method also radiated reddish fluorescence under blue light. In white light mode, they revealed one was “carcinoma in adenoma” and the other was “adenoma with no signs of cancer” (Figures 2, 3 and 4). Discussion Using PDHD method, we could visually discriminate cancer from normal tissue by identifying reddish-pink fluorescence. In the previous study, we could also diagnose bile tract cancer by our own PDCD [6]. While in this study, we could not distinguish an adenoma Correspondence to: Akio Sugitachi, MD, PhD, Department of Surgery, Iwate Medical University, 1-19, Uchimaru, Morioka 020-8505, Japan, Tel: 019-6515111; Fax: 019-651-7166; E-mail: akiosugi@iwate-med.ac.jp