The Impact of Cancer

Cancer is a group of diseases that characteristically grow in an uncontrolled manner with the spread of abnormal cells. In many instances, however, the growth can be controlled by specific treatment. In the early 1900s, there was little hope for survival once cancer was detected. This year, 4 of 10 people who are diagnosed with cancer will be alive in 5 years.

Excluding skin cancer, about 1,529,560 new cases of invasive cancer will be diagnosed in 2010 (American Cancer Society [ACS], 2010). It is estimated that an additional 1 million people in 2010 will be told that they have squamous cell skin cancer. The current rate of cancer is about the same as that of 1977, indicating little advance in the rate of cancer occurrence. The incidence of lung cancer in men declined during 2010 and the incidence in women stabilized. However, the incidence of breast cancer has increased over the past three decades and is mostly attributed to improved detection.

Physiology of Cancer

The human body is continuously producing new cells to replace those cells that are worn out, and to repair damage done to cells by illness and injury. An abnormal replication of cells results in a neoplasm (new growth of tissue, or tumor), which is not beneficial. The word benign indicates a neoplasm that is usually harmless. Benign growths are almost always encapsulated (surrounded by a fibrous capsule). The capsule prevents the release of cells and restricts their spread to other parts of the body. Benign growths can, however, create problems if they press against and interfere with the normal structure and function of nearby organs.

The nucleus of a malignant (cancer) cell is large and irregular. As the cancer cell divides and duplicates, it fails to follow the rules that regulate the reproduction of normal cells. Malignant cells do not seem to “know” when to stop multiplying. The offspring of cancerous cells proliferate (multiply) in great numbers, and they grow more and more disorganized, often forming tumorous masses. Some cancerous cells take on new characteristics, so that they do not resemble the cells of the original tissue. The malignant cells invade neighboring tissues and travel to other parts of the body. There they establish another colony of malignant cells. Their demand for nutrients depletes the supply of nourishment available for normal cells. This spread of tumor cells is called metastasis (movement of cancer cells from the original cancer site to other areas of the body). Not all malignant cells metastasize, but the great majority of malignant cells do.

Classification of Tumors

Tumors are often classified according to the organs or tissues from which they first began to grow; alternatively, tumors are classified according to the substances of which they are formed. The suffix -oma means tumor; this suffix is used in the names of various kinds of growths or swellings. Remember that -oma simply means tumor; the suffix -oma can designate any swelling, including a swelling in which there is a collection of fluids, as well as a swelling containing malignant cells. For example, hematoma (another word for bruise) is a combination of hema-, meaning blood, and -oma, meaning a swelling or collection of fluid or cells.

The prefixes used in classifying neoplasms indicate the kind of tissue in which they originate. For example, a tumor arising from fatty (lipoid) tissue is called a lipoma. A fibroma is a tumor composed of fibrous tissue. A leiomyofibroma contains both smooth-muscle tissue and fibrous connective tissue. Lipomas, fibromas, and leiomyomas are the most frequently occurring types of benign growths.

Malignant growths are divided into four main types. A sarcoma arises from mesenchymal tissues (bone, muscles, and other connective tissues). A carcinoma originates in epithelial tissues (skin and mucous membranes). These kinds of cancers make up the majority of cancers of the stomach, uterus, lungs, skin, and tongue. Leukemia and lymphoma are cancers of the blood-forming system. Malignancy of the pigment cells of the skin is called melanoma.

These are the main groups of cancers. More accurate naming can be done by adding modifying prefixes. For example, osteosarcomas arise from bone (osteo-), and adenocarcinomas arise from glandular (adeno-) structures.

Metastasis

The prognosis (prediction of survival) for a patient with a malignancy depends on how much the malignant cells have attacked body tissues. A localized growth is one that remains at the original site (in situ) and has not yet released its cells, even though the growth may have invaded underlying tissues. At this stage the disease is much more easily destroyed.

A regional malignancy is one in which cells from the original malignancy have spread to the body area around the tumor, such as to nearby lymph nodes. The spread has been limited by the body’s protective mechanisms. These cells may continue to grow and multiply, and if the regional cancer is not successfully treated, malignant cells will eventually break away and spread throughout the body. This creates an advanced cancer that is often fatal.

One system that identifies cancers by how much the malignancy has spread is the TNM staging system. The three basic parts of the system are T for primary tumor, N for regional nodes, and M for metastasis. The number written beside each letter indicates how much the malignancy has spread and attacked other tissues. For example, T1, N0, M0 means that the tumor is small and localized (no involvement of regional lymph nodes and no metastasis). A label of T1, N2, M1 indicates a small (T1) tumor with moderate regional involvement (N2) that has metastasized to one distant site or organ (M1).

Causative Factors

All cancer results from defects in the DNA of genes. These defects either are inherited or are caused by mutation (a permanent change in the DNA sequence of a gene) during a person’s lifetime from exposure to chemicals or radiation. Several cancer-causing genes (oncogenes) are discovered each year. Oncogenes are mistakes in the instructions inside a cell’s DNA genetic code, whereby newly created cells are no longer normal. The defective gene tells the new cells to multiply at a higher rate. Also, the defective coding prevents newly created defective cells from dying and being reabsorbed. This results in a tumor, or mass.

Tumor suppressor genes are healthy, normal genes that control the growth of cells in the body. Each person’s body has a different ability to withstand the effects of cancer-causing substances (carcinogens), to mount a healthy immune response, and to repair damaged DNA. It is hoped that discoveries in molecular biology will allow individual risk profiles to be drawn that could be used to counsel people to avoid certain occupational and environmental exposures or to develop protective therapies.

Another factor that enters into the development of a malignancy is age. Although cancer can strike at any age, older people are more susceptible. Immunocompetence, or the capability of one’s immune system to deal with foreign cells—bacterial, viral, or malignant—is an important factor in the development of cancers; immunocompetence decreases with aging.

Contributing Factors

Measures to Prevent Cancer

The nurse can be instrumental in educating the public about ways to prevent cancer. Each nurse should teach patients the following measures at every opportunity.

Detection of Cancer

Cancer is a group of diseases. It can strike any organ of the body, affect different organs with different functions, and therefore can present an untold number of symptoms as it progresses. To be able to identify the symptoms of cancer in its earliest stages, it is important to be aware of its warning signals. The purpose of screening large segments of a population is to identify as many people with cancer as possible.

One widely used technique to detect cancer is to examine cells under a microscope to determine whether they are malignant or premalignant. This technique is called cytology, and the most widely used cytology test is the Papanicolaou (Pap) smear to detect cervical cancer. A cytologic examination can be done by obtaining a sample of secretions containing cells that have been released from adjacent tissue. The technique involves either scraping or brushing a sample of cells from the area or collecting body secretions that contain cells. These secretions may be cervical discharges, sputum, gastric washings, pleural fluid, or urinary washings. The specimen is placed on a slide or put in a liquid medium and sent to a laboratory, where a specially trained technologist or pathologist examines the cells microscopically. If “suspicious” cells are found, the patient is referred to a health care professional for more extensive diagnostic tests. Another screening technique, used for colorectal cancer, is the simple test for occult blood (hidden blood) in the stool. This can be obtained through a fecal occult blood test (FOBT) or a newer test called the fecal immunochemical test (FIT). The person simply collects one or more stool specimens (depending on the particular test being used), applies a thin smear on the container provided, and returns the specimens to the health center, clinic, or clinical laboratory. Occult blood in the stool is not always an indication of cancer of the bowel or rectum. Other conditions also can produce this symptom.

Research continues on identifying proteins produced by mutated DNA that might be used to diagnose various types of cancer. These tests may soon be available for those at high risk for bladder, cervical, lung, breast, colon, and prostate cancer. If these tests prove reliable, they may well be incorporated into a normal part of routine medical care.

Other procedures used to identify lesions that are possibly malignant include radiologic studies, endoscopy, sonography, magnetic resonance imaging, computed tomography, clinical laboratory testing of enzymes and other substances in the blood, and studies specific to the system in which the cancer is suspected. Tests for viruses are now being done to identify increased risk for some cancers. For example, a test for the presence of high-risk types of HPV is available to identify women at risk for cervical cancer.