Evaluation and Validation of Raman Spectroscopic Diagnostic Methodology of Cervix Cancers by Blind Studies

Abstract

Validate Raman spectroscopic diagnostic method of cervix cancer developed by us,4 by blind studies (preclinical trials) where the spectroscopist doesn't know nature of the sample, before it is routinely used. Cervical cancer is the second most common cancer in women worldwide.1 Pap smear and colposcopy are widely used screening methods which are shown to suffer from false negative/positive results that could be due to the subjective interpretations.2, 3 Hence there exits a need for development of new methodology, to detect malignancy at an early stage. Raman spectroscopic methods are shown as potential diagnostic tools for cancer diagnosis.4,5 In this study we have analyzed 20 biopsies, collected from Dept. of Radiotherapy and Oncology and Dept. of OBG, KMC, Manipal; among them 12 are malignant and 8 are normal as per histopathological report. Atleast 6 spectra were recorded from a tissue and each spectrum is treated as separate sample. Preprocessed spectra (baseline corrected, normalized to δCH2 peak) were analyzed by ‘limit test’. ‘Limit test’ is typical match/mismatch approach where test spectrum is compared against normal and malignant standard sets which were developed by us earlier, and results of which are correlated with histopathology report. Basing on match/mismatch against standard sets spectra are labeled as YES/POSSIBLE or NO. Sample 1 and 2 (Table 1) can be diagnosed unambiguously as malignant and normal, respectively as they match one standard set mismatch with other. In the case of sample 3 all spectra match with malignant standard set but for one spectrum all do not match with normal standard set, so it is treated as malignant. Conventionally even one spectrum matches with malignant standard set should be treated as malignant. On the other hand, no spectra of sample 4 match with malignant standard set and excepting one spectrum rest match with normal standard set so it is treated as normal. It is possible to make unambiguous discrimination of Normal from Malignant cervix tisssues by Raman Spectroscopic method.