5/13/94
Pathology would remain a lovely science, even if there were no therapeutics, just as seismology is a lovely science, though no one knows how to stop earthquakes.
H.L. Mencken (1880-1956)
If a physician usually can't tell by looking at, or feeling, a tumor, whether it is benign or malignant, how is it done? The way that it is done is to take a piece of the tumor, slice it tissue paper thin, stain it and look at it under a microscope. This examination is done by a pathologist. He is someone who has finished medical school and specialized in pathology. This involves a long apprenticeship during which he learns to distinguish various diseases both by examining the patient after death and by examining those thin slices of stained tissue. What he learns is not how to use a crystal ball, but the accumulated information contributed by pathologists since the beginning of the science. It is both a science and an art which is continually changing, hopefully toward greater reliability. One aim of pathology is to predict the future. Some of those predictions approach 100%, but not when it comes to cancer. With cancer, the level of accuracy depends on the skill of the pathologist. As with all professions, skills range from low to high, with most members being sort-of in the middle. It is for this reason that I prefer judgments made about me to be made cautiously, taking lots of time, and often getting a second opinion.
How does a pathologist make his diagnosis? He does it in much the same way as Sherlock Holmes did his detective work. Arthur Conan Doyle (1859-1930), a physician, modeled his detective after his professor of pathology. He examines his specimen, both as it is and under the microscope. His train of reasoning begins with the knowledge that there is a tumor to begin with. What could cause that tumor? It could be an infection. The presence of infection is easy to detect with the microscope. It could be a cyst, which is made up of secreting cells surrounding a ball of secretions. If it isn't an infection or a cyst, what is left is a neoplasm (new growth). With breast tumors, most tumors are common enough so that the pathologist is able to recognize them instantly as we recognize an old friend -or enemy. Less common types are more difficult, and some are so difficult, that he may have to consult with a specialist on breast tumors. There are a rare few where even the experts have to admit that they just don't know.
Based on its appearance, the pathologist will give the tumor a name; he will make a diagnosis. That name will guide the surgeon. There is information avilable in the medical literature as to what might happen to a patient with any particular type of tumor. If he calls it a cyst or a fibroadenoma, a common benign tumor, the surgeon will send his happy patient home with no more worries. If it is an adenocarcinoma (gland cancer), the diagnosis implies that if the tumor isn't removed completely, it may spread and kill the patient. He can sometimes tell if it has spread by examining the patient's lymph nodes, which may have been removed by the surgeon, and he can also detect a tendency to invade adjacent structures, under the microscope. Yet, there are limits to those predictions, because his diagnosis may not reveal what the cancer will do. There are always surprises, and some cancers aren't as deadly as they look; nor are others as innocuous as they look. Yet, it is surprising, considering the variables, how accurate the diagnoses of an expert pathologist can be and how accurate predictions, based on those diagnoses, can be.