Although a doctor may suspect cancer, a diagnosis cannot be established without examining a piece of the suspicious tissue under the microscope.
If the cancer is situated on the surface of the body, taking biopsy is easy. If, however, it is situated inside the body, then the surgeon has to open up the overlying part, reach in and then take the biopsy.
Biopsy can also be taken by passing a lighted tube in a hollow organ, (endoscope). When it reaches the involved organ, a piece of the involved tissue is taken with the help of a needle or a punch, coming from inside the endoscope. The piece of tissue taken is then processed and examined under the microscope.
Cancer-markers in the Blood
Cancer cells differ from normal cells histologically. The biochemicals they produce and pour in the blood are also different. The presence of cancer tissue in the body, may be detectable by the presence in the blood of biochemical products known as cancer or tumour-markers. These are normal metabolic constituents that are found either in abnormal amounts or at an inappropriate time of life, for example, foetal proteins being re-expressed in adult life. Tumour-markers of this type are useful in making diagnosis of some cancers. The presence of a tumour-marker can also be of clinical value in monitoring the progress of individual patients known to have a particular cancer.