Over 1.4 million individuals in the United States are diagnosed
with invasive cancer each year. Currently, 1 in 4 deaths in the United
States is due to cancer, ranking second only to heart disease as
the leading cause of mortality in this country. Before age 65, among
men and women combined, cancer is the leading cause of death.
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.
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.
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.
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, tumor grade has great clinical significance in soft tissue
sarcoma, astrocytoma, transitional cell cancers of the genitourinary
tract, and Hodgkin and non-Hodgkin lymphoma.
Tumor staging establishes the extent of disease and has important
prognostic and therapeutic implications ...