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Over 1.6 million individuals in the United States are diagnosed with invasive cancer each year. Currently, 23% of all deaths in the United States are due to cancer, ranking second only to heart disease as the leading cause of mortality in this country. Over the past 10 years, however, cancer death rates have decreased. Death rates have continued to decline for the four top cancer sites (lung, colorectum, breast, and prostate). This reduction in overall cancer death rates translates to the avoidance of over 1 million deaths from cancer.
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The surgeon is intimately involved in the care of cancer patients, since the majority will require surgical therapy at some time. Surgeons are often the first specialists to see newly diagnosed cancer patients or are often called upon to make the diagnosis in patients suspected to have cancer. As such, they will be responsible for orchestrating the patient’s care, including coordination with medical oncologists and radiation oncologists. It is imperative that they have an in-depth knowledge of the different types of cancer and the different modalities available for treatment.
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Neoplasms are defined as benign or malignant according to the clinical behavior of the tumor. Benign tumors have lost normal growth regulation but tend to be surrounded by a capsule and do not invade surrounding tissues or metastasize.
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Benign tumors are generally designated by adding the suffix -oma to the name of the cell of origin. Examples include lipoma and adenoma. The term cancer normally refers to malignant tumors, which can invade surrounding tissues or metastasize to distant sites in the host. The nomenclature of malignant tumors is typically based on the cell’s embryonal tissue origins. Malignant tumors derived from cells of mesenchymal origin are called sarcomas. These include cancers that derive from muscle, bone, tendon, fat, cartilage, lymphoid tissues, vessels, and connective tissue. Neoplasms of epithelial origin are called carcinomas. These may be further categorized according to the histologic appearance of the cells. Tumor cells that have glandular growth patterns are called adenocarcinomas, and those that resemble squamous epithelial cells are called squamous cell carcinomas. Cancers composed of undifferentiated cells that bear no resemblance to any tissues are designated as “poorly differentiated” or “undifferentiated” carcinomas.
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Beyond the type of cancer, it is important to classify tumors by their behavior and prognosis in order to determine appropriate therapy as well as evaluate different treatment modalities. Grading of a tumor is a histologic determination and refers to the degree of cellular differentiation. Separate pathologic grading systems exist for each histologic type of cancer. Depending on the type of tumor, these systems are based on nuclear pleomorphism, cellularity, necrosis, cellular invasion, and the number of mitoses. Increasing grades generally denote increasing degrees of dedifferentiation. While the grade of the tumor typically has less prognostic value than its stage, ...