‘Incision’ means cutting out part of, ‘excision’ means cutting out the whole of an abnormal area. This can be done with scalpels etc in the form of a mini-operation or with special forceps and other instruments designed to neatly nip off a tiny sample. Such instruments are available for taking specimens from internal lesions through endoscopy tubes. Because of this, endoscopy is a very useful type of test—we can see the abnormality and get a specimen from it in the one procedure. In many cases, these specimens are from spots which, in the past, could only have been biopsied at a full scale operation. Endoscopy can be uncomfortable, Wit it’s certainly much safer, simpler, more convenient and less painful than an operation!
As I explained in the previous section, if lesions can’t be reached through the skin or by endoscopy, an operation may be necessary to get a specimen. As with every type of specimen that consists of only a small fragment of the abnormal area, incision biopsies are only helpful if they are positive, that is, give a definite diagnosis. A negative biopsy can only rule out cancer when the whole lesion is removed and examined under the microscope. An excision biopsy may be recommended whenever a conclusive diagnosis cannot be made using the other methods I have described. In the case of enlarged lymph nodes, it is usually best to remove one completely anyway. This is because lymph node conditions can be diagnosed much more accurately and reliably when the pathologist can see the pattern of the whole node and not just a few cells from one part of it.