Methods and apparatus for detection, assessment and optionally treatment of the cancerous tissue in the natural and manmade body cavities. An expandable cavity assessment device that is coupled with cancer detecting elements is placed in a cavity in close proximity to the site of cancerous tissue. The cavity assessment device may receive an optical fiber, or other type of energy conduit and potentially a radioactive source for interstitial radiation therapy. The cavity assessment device may be equipped with a balloon member coupled with electro conductive elements. Further, a system facilitating substance communication with the internal surface of the cavity is provided.