The word cancer is derived from the Latin word for crab because cancers are often very irregularly shaped, and because, like a crab, they "grab on and don't let go." The term cancer specifically refers to a new growth which has the ability to invade surrounding tissues, metastasize (spread to other organs) and which may eventually lead to the patient's death if untreated.
The terms tumor and cancer are sometimes used interchangeably which can be misleading. A tumor is not necessarily a cancer. The word tumor simply refers to a mass. For example, a collection of fluid would meet the definition of a tumor. A cancer is a particularly threatening type of tumor. It is helpful to keep these distinctions clear when discussing a possible cancer diagnosis.
|neoplasm-||A neoplasm is an abnormal new growth of cells. The cells in a neoplasm usually grow more rapidly than normal cells and will continue to grow if not treated. As they grow, neoplasms can impinge upon and damage adjacent structures. The term neoplasm can refer to benign (usually curable) or malignant (cancerous) growths.|
|tumor-||A tumor is a commonly used, but non-specific, term for a neoplasm. The word tumor simply refers to a mass. This is a general term that can refer to benign (generally harmless) or malignant (cancerous) growths.|
|benign tumor-||Benign tumors are non-malignant/non-cancerous tumor. A benign tumor is usually localized, and does not spread to other parts of the body. Most benign tumors respond well to treatment. However, if left untreated, some benign tumors can grow large and lead to serious disease because of their size. Benign tumors can also mimic malignant tumors, and so for this reason are sometimes treated.|
|malignant tumor-||Malignant tumors are cancerous growths. They are often resistant to treatment, may spread to other parts of the body and they sometimes recur after they were removed.|
|cancer-||A cancer is another word for a malignant tumor (a malignant neoplasm).|
Cancer of the pancreas is a malignant neoplasm that arises in the pancreas. It strikes approximately 9 out of every 100,000 people every year in the United States and is one of the deadliest forms of cancer. It is estimated that this year 45,000 Americans will be diagnosed with cancer of the pancreas. An almost equal number of patients (some diagnosed previous to this year) will die from pancreatic cancer during this year.
Cancer of the pancreas is not one disease. In fact, as many as twenty different tumors have been lumped under the umbrella term "cancer of the pancreas." Each of these tumors has a different appearance when examined with a microscope, some require different treatments, and each carries its own unique prognosis (predicted or likely outcome). An understanding of the different types of neoplasms of the pancreas is required for rational treatment. different types of pancreatic tumors is required for rational treatment.
Cancers of the pancreas can be broadly classified as:
|Primary-||Primary cancers are those that arise in the pancreas itself.|
|Metastatic-||tMetastatic cancers are cancers that arise in other organs and only later spread to the pancreas. These are usually not considered a pancreatic cancer, instead they are considered cancers of the organs from which they arose.|
In the vast majority of cases the term "cancer of the pancreas" refers to primary cancers of the pancreas — cancers that arose in the pancreas. Primary cancers of the pancreas can be broadly subgrouped into those that look like endocrine cells under the microscope (have endocrine differentiation) and those that look like exocrine cells under the microscope (have exocrine differentiation). The distinction between endocrine neoplasms and exocrine neoplasms is very important and will greatly impact on treatment and outcome.
Pathologists examine histological slides (slides of tissue samples) using a microscope to diagnose and classify pancreatic cancer. To make the cells visible the slides are stained with various dyes. A change in color from one slide to another does not indicate any disease or abnormality. The different colors indicate that a different dye has been used or a different part of the cells is stained. Pathologists identify abnormalities by changes in the size, shape or arrangement of cells. The classification of neoplasms of the pancreas given below is based on pathological examination.