Method and system for early detection of precancerous and other abnormal changes in tissue of various organs. The system comprises a combination of endoscopic scanning with light scattering spectroscopy and improves detection of abnormalities that may otherwise remain undetected. The system may include a probe that collects data of quality that is independent of a distance of the probe from the scanned tissue. During endoscopy, tissue of an organ is imaged using polarized multispectral light scattering scanning and results are presented to a user in a manner that allows detecting abnormal morphological and biochemical changes in the tissue. A determination of whether to perform biopsy may be performed while the endoscopy is being performed, which thus provides guided biopsy. An entire surface of the organ may be rapidly scanned and results of the scanning are analyzed with a reduced time delay.
