the staging of a cancer refers to determining the extent of the disease. once a prostate cancer is diagnosed on a biopsy additional tests are done to assess whether the cancer has spread beyond the gland. for this assessment biopsies of the surrounding organs such as the rectum or urinary bladder or of the nearby (pelvic) lymph nodes might be done. in addition imaging tests are usually performed. for example radionuclide bone scans can determine if there is a spread of the tumor to the bones. additionally ct scans (computed tomography) and mris (magnetic resonance imaging) can determine if the cancer has spread to adjacent tissues or organs such as the bladder or rectum or to other parts of the body such as the liver or lungs. newer scanning using a method called pet scan can sometimes help to detect hidden locations of cancer that has spread to various areas of the body. in brief doctors do the staging of prostate cancer based primarily on the results of the prostate biopsy possibly other biopsies and imaging tests. in staging a cancer doctors assign various letters and numbers to the cancer depending on which of the classifications for staging they use. the numbers and letters in the different classifications define the volume or amount of the tumor and the spread of the cancer. the stage of the prostate cancer therefore helps to predict the expected course of the disease and determine the choice of treatment. two main systems are used to stage prostate cancer. in the american urological staging system stage a describes a minimal cancer that can neither be palpated (felt) on physical examination nor seen by imaging techniques. such a tumor is so small that it can be detected only by viewing it under a microscope. stage b refers to a larger cancer that may be felt but that still is confined (localized) to the prostate gland. stage c indicates local spread beyond the prostate into the surrounding tissues. stage d1 signifies a spread to the nearby (pelvic) lymph nodes and d2 is for distant spread (metastasis) for example to the bones liver or lungs. the other main system for staging prostate cancer is called the t umor n odes and m etastasis (tnm) classification. in this system t1 and t2 are equivalent to stage a and b (respectively) in the american urological system. t3 describes cancer that extends just beyond the capsule (coat) of the prostate and t4 describes cancer that is fixed to the surrounding tissues. n1 is equivalent tosstage d1 and m1 is equivalent to d2.
how is the staging of prostate cancer done?