Cancer Education

General Information

What is Cancer?
Cancer refers to a large number of diseases characterized by abnormal cells in a part of the body that divide and begin to grow out of control. These cells can spread throughout the body through the blood and lymph systems and destroy normal body tissue. There are over 100 different types of cancer that can affect just about every organ in the human body. Untreated cancers can cause serious illness and even death.

Who Gets Cancer?
Over one million people get cancer each year. According to the American Cancer Society, approximately one out of every two American men and one out of every three American women will have some type of cancer during their lifetime. While cancer can strike at any age, about 77% of all cancers are diagnosed in people aged 55 and older. And while cancer occurs in all racial and ethnic groups, the rate of cancer occurrence varies from group to group.

Today, millions of people are living with cancer or have been cured of the disease. The sooner a cancer is found and the sooner treatment begins, the better a patient's chances are of a cure. Early detection and treatment of cancer is critical.

How Does Cancer Develop?
The organs in the body are made up of cells. Normal body cells divide and multiply as the body needs them. When these cells continue multiplying when the body doesn’t need them, the result can be a mass or tumor. These growths are defined as either benign (noncancerous) or malignant (cancerous). Benign tumors are seldom life threatening, can often be removed, and do not spread to other parts of the body. Some cancers, like leukemia, do not form tumors. Instead, these cancer cells involve the blood and blood-forming organs and circulate through other tissues where they grow.


Most cancers are caused by abnormalities in the genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other cancer promoting genetic abnormalities may be acquired through errors in DNA replication, or are inherited, and thus present in all cells from birth. Complex interactions between carcinogens and the host genome may explain why only certain people develop cancer after exposure to a known carcinogen.

Risk Factors
Risk factors for cancer include age, sex, and family medical history. Other risk factors are related to cancer-causing factors in the environment. Still others are linked to lifestyle choices such as tobacco and alcohol use, diet, and sun exposure.

Having a risk factor for cancer simply means that a person is more likely to develop the disease at some point in their lives. However, having one or more risk factors does not necessarily mean that a person will get cancer. Some people with one or more risk factors never develop the disease, while other people who do develop cancer have no apparent risk factors. Even when a person who has a risk factor is diagnosed with cancer, there is no way to prove that the risk factor actually caused the cancer.

The American Cancer Society reports that environmental factors, defined broadly to include tobacco use, diet, and infectious diseases, as well as chemicals and radiation cause an estimated 75% of all cancer cases in the United States. Among these factors, tobacco use, unhealthy diet, and physical activity are more likely to affect personal cancer risk. Research shows that about one-third of all cancer deaths are related to dietary factors and lack of physical activity in adulthood.

Can Cancer be Prevented?
Smoking and drinking alcohol cause some people to get certain types of cancer and these cancers might be prevented by avoiding tobacco and alcohol. The best idea is to never use tobacco at all. Cigarettes, cigars, pipes and smokeless tobacco cause cancer and should not be used. People who already smoke should quit. Former smokers have less risk of cancer than do people who continue to smoke.

The chances of getting skin cancer can be lowered by staying in the shade as much as you can, wearing a hat and shirt when you are in the sun, and using sunscreen. We know that our diet is linked to some types of cancer, although the exact reasons are not yet clear. The best advice is to eat fresh fruits and vegetables and whole grains like pasta and bread, and to cut down on high fat foods. Screening examinations can also help identify early forms of cancer in adults. If cancer is found early it can often be cured.

Heredity and Cancer
Cancer is now clearly understood to be a disease of abnormal gene function. Genes are segments of DNA that contain instructions on how to make the proteins the body needs to function. They govern hereditary traits, such as hair color, eye color, and height, as well as susceptibility (likelihood of being affected) to certain diseases, such as cancer.

In humans, genes are located on 23 pairs of chromosomes. One of each chromosome pair comes from the mother, the other from the father. Each chromosome can contain hundreds or thousands of genes that are passed from the parents to the child.

We now understand that genes serve two major roles in cancer: some contribute to the development of cancer and others stop cancer from developing or growing. Genes that can cause cancer are called oncogenes. Genes that stop or suppress cancer growth are called tumor suppressor genes. Even if a person is born with healthy genes, some of them can change or mutate. For example, exposure to large doses of radiation can change the genes of some of the body’s cells. This explains why most cancers are not inherited but arise from gene mutations acquired later in life. As people age, the more gene mutations continue to accumulate. This is why cancer risk increases with age. In contrast, cancers that are inherited tend to occur earlier in life than cancers of the same type that are not inherited.

Genetic Counseling and Testing
Individuals with a strong family history of cancer or multiple types of cancer may want to investigate genetic testing. The knowledge gained from this testing may help the individual or family members plan health care for the future. Since inherited mutations affect all cells of a person's body, they can often be identified by genetic testing on blood samples. Genetic counseling and testing may be recommended for some people with a strong family history of cancer.

Signs & Symptoms
There are many different signs and symptoms that can lead to a medical diagnosis of cancer. It is crucial to discuss any specific symptoms with a physician. The following symptoms should be reported to a medical professional:

— Unexplained Weight Loss
— Fever
— Fatigue
— Pain
— Skin Changes
— Change in Bowel Habits or Bladder Function
— Sores That Do Not Heal
— Unusual Bleeding or Discharge
— Thickening or Lump in Breast or Other Parts of the Body
— Indigestion or Trouble Swallowing
— Recent Change in a Wart or Mole
— Nagging Cough or Hoarseness

Generally, cancer symptoms can be divided into three groups:

Local symptoms: unusual lumps or swelling, hemorrhage, pain and/or ulceration. Compression of surrounding tissues may cause  symptoms such as jaundice (yellowing of the eyes and skin).

Symptoms of metastasis (spreading): enlarged lymph nodes, cough and/or cough with blood, hepatomegaly (enlarged liver), bone pain, fracture of affected bones, and neurological symptoms. Although advanced cancer may cause pain, it is often not the first symptom.

Systemic symptoms: weight loss, poor appetite, fatigue, excessive sweating (night sweats), anemia and hormonal changes.

Diagnosis
A cancer may be suspected for a variety of reasons, but the definitive diagnosis of most malignancies must be confirmed by an examination of the cancerous cells by a pathologist. Tissue can be obtained from a biopsy or surgery. Many biopsies (such as those of the skin, breast or liver) can be done in a doctor's office. Biopsies of other organs are performed under anesthesia and require surgery in an operating room. The tissue diagnosis given by the pathologist indicates the type of cell that is proliferating, its histological grade, and other features of the tumor. Together, this information is useful to evaluate the prognosis and to choose the best treatment.

What is Staging?
Once cancer has been diagnosed, the next step is to determine how far the cancer has spread, or staging. Staging is an important step in determining treatment choices and it also gives the healthcare team a clearer idea of the outlook for recovery.

One system for staging is the TNM system which provides three key pieces of information:
T = Describes the size of the tumor and if the cancer has spread to tissues and organs
N = Describes how far the cancer has spread to nearby lymph nodes.
M = Describes how the cancer has metastasized to other organs of the body.

Letters or numbers following the T, N, M give more details about each of these factors. For example, a tumor classified as T1, N0, M0 is a tumor that is very small, has not spread to the lymph nodes, and has not spread to distant organs of the body.

Once the TNM descriptions have been established, they can be grouped together into a simpler set of stages – Stages 1 through IV. Typically, the lower the number, the less the cancer has spread. Stage IV cancer, however, means a more serious, widespread disease.

Treating Cancer
Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for different varieties of cancer. There has been significant progress in the development of targeted therapy drugs that act specifically on detectable molecular abnormalities in certain tumors, and which minimize damage to normal cells. The prognosis of cancer patients is most influenced by the type of cancer as well as the stage.



The goal of treating cancer is to completely remove the cancer without damaging the rest of the body. Sometimes this can best be accomplished by surgery, but the propensity of cancers to invade adjacent tissue or to spread to distant sites by microscopic metastasis often limits its effective- ness. The effectiveness of chemotherapy is often limited by toxicity to other tissues in the body. Radiation can also cause damage to normal tissue.

Cancer treatment will be based on each person’s unique situation. Some cancers respond very well to certain treatments. The cancer’s stage will also determine the course of treatment as early-stage cancers respond differently than later stage cancers. Overall health, lifestyle, and personal preferences will also play a part in deciding which treatment options are best.

Surgery
In theory, some cancers can be cured if entirely removed by surgery, but this is not always possible. When the cancer has metastasized to other sites in the body, complete surgical excision can be difficult. In the typical cancer progression, tumors grow locally then spread to the lymph nodes then to the rest of the body. This has given rise to the popularity of local-only treatments such as surgery for small cancers. Even small localized tumors are increasingly recognized as possessing metastatic potential.



Examples of surgical procedures for cancer include mastectomy for breast cancer and prostatectomy for prostate cancer. The goal of the surgery can be either the removal of only the tumor, or the entire organ. A single cancer cell is invisible to the naked eye but can regrow into a new tumor, a process called recurrence. For this reason, the pathologist will examine the surgical specimen to determine if a margin of healthy tissue is present, thus decreasing the chance that microscopic cancer cells are left in the patient.

In addition to removal of the primary tumor, surgery is often necessary for staging, e.g. determining the extent of the disease and whether it has metastasized to regional lymph nodes. Staging is a major determinant of prognosis and of the need for adjuvant therapy.

Occasionally, surgery is necessary to control symptoms, such as spinal cord compression or bowel obstruction. This is referred to as palliative treatment.

Radiation Therapy
Radiation therapy (also called radiotherapy, X-ray therapy, or irradiation) is the use of ionizing radiation to kill cancer cells and shrink tumors. Radiation therapy can be administered externally via external beam radiotherapy (EBRT) or internally via brachytherapy. The effects of radiation therapy are localized and confined to the region being treated. Radiation therapy injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue. Therefore, it is given in many small doses, allowing healthy tissue to recover between treatments.

Chemotherapy
Chemotherapy is the treatment of cancer that has metastasized to other parts of the body with powerful medicines that can destroy cancer cells. The term chemotherapy usually refers to cytotoxic drugs which affect rapidly dividing cells in general, in contrast with targeted therapy. Chemotherapy drugs interfere with cell division in various possible ways, e.g. with the duplication of DNA or the separation of newly formed chromosomes. Most forms of chemotherapy target all rapidly dividing cells and are not specific for cancer cells, although some degree of specificity may come from the inability of many cancer cells to repair DNA damage, while normal cells generally can. Therefore, chemotherapy has the potential to harm healthy tissue, especially those tissues that have a high replacement rate. These cells usually repair themselves after chemotherapy. Because some drugs work better together than alone, two or more drugs are often given at the same time. This is called combination chemotherapy and most chemotherapy regimens are given in a combination.

Biologic Therapies
Biologic therapies refer to strategies designed to induce the patient’s own immune system to fight the cancer or to lessen the side effects of some cancer treatments. Biologic therapy may be used alone or in combination with chemotherapy or radiation therapy to treat cancer.

Complementary and Alternative Therapies
Complementary medicine refers to methods and substances used along with conventional medicine, while alternative medicine refers to compounds used instead of conventional medicine. Some complementary measures include botanical medicine, such as an NIH trial currently underway testing mistletoe extract combined with chemotherapy for the treatment of solid tumors; acupuncture for managing chemotherapy-associated nausea and vomiting and in controlling pain associated with surgery; and psychological approaches such as imaging or meditation to aid in pain relief or improve mood.

A wide range of alternative treatments have been offered for cancer over the last century. These treatments can include vitamins, herbs, or dietary supplements or procedures such massage, relaxation therapies, etc.

Symptom Control
Although the control of the symptoms of cancer is not typically thought of as a treatment directed at the cancer, it is an important determinant of the quality of life of cancer patients, and plays an important role in the decision whether the patient is able to undergo other treatments. Although doctors generally have the therapeutic skills to reduce pain, nausea, vomiting, diarrhea, hemorrhage and other common problems in cancer patients, the multidisciplinary specialty of palliative care has arisen specifically in response to the symptom control needs of this group of patients.

Clinical Trials
Clinical trials, also called research studies, test new treatments in people with cancer. The goal of this research is to find better ways to treat cancer and help cancer patients. Clinical trials test many types of treatment such as new drugs, new approaches to surgery or radiation therapy, new combinations of treatments, or new methods such as gene therapy.

A clinical trial is one of the final stages of a long and careful cancer research process. The search for new treatments begins in the laboratory, where scientists first develop and test new ideas. If an approach seems promising, the next step may be testing a treatment in animals to see how it affects cancer in a living being and whether it has harmful effects. Of course, treatments that work well in the lab or in animals do not always work well in people. Studies are done with cancer patients to find out whether promising treatments are safe and effective.

Patients who take part may be helped personally by the treatment(s) they receive. They get up-to-date care from cancer experts, and they receive either a new treatment being tested or the best available standard treatment for their cancer. Of course, there is no guarantee that a new treatment being tested or a standard treatment will produce good results. New treatments also may have unknown risks, but if a new treatment proves effective or more effective than standard treatment, study patients who receive it may be among the first to benefit.

Talking With Your Doctor
Communication between the patient and the physician is an important part of patient care and recovery. Ideally, one doctor will coordinate all patient care, however, there may be a team of doctors and nurses with specialized knowledge and skills who will work along with the primary doctor.

To make sure that all patient questions are addressed, it may be helpful to maintain a notebook and/or bring a family member or friend to help keep track of all the information.Here are examples of commonly asked questions:

— What type of cancer do I have?
— What is the stage or extent of my cancer?
— What is my prognosis?
— What treatment to you recommend?
— What is the goal of my treatment?
— Will this cure my cancer or control my symptoms?
— What are the possible risks or side effects of treatment?
— What are the pros and cons of treatment?
— Are there other treatments?
— How long will the treatment take?
— What if I miss a treatment?
— How will we know if the treatment is working?
— What if the treatment doesn’t work?
— How will my life change?
— Will I need to make changes in  my work schedule, family life, etc.?
— What are the names of the drugs I will be taking?
— What are they for and how long will I be taking these drugs?
— If other specialists take part in my care, who will coordinate  my entire treatment program?
— What symptoms should I report right away?
— What are the chances that my cancer will reoccur?
— When will I be ready for treatment?
— Are there foods I should avoid before treatment?
— Can I take over-the-counter medications?

Common Definitions
Adjuvant therapy: treatment, either chemotherapy or radiation therapy, given after surgery to kill the remaining cancer cells.

Benign neoplasm or benign tumor: a tumor (solid neoplasm) that stops growing by itself, does not invade other tissues and does not form metastases.

Chemotherapy: treatment of cancer that has metastasized to other parts of the body with cytotoxic drugs designed to destroy cancer cells.

Diagnosis: the confirmation of the cancerous nature of a lump. This usually requires a biopsy or removal of the tumor by surgery, followed by examination by a pathologist.

Grade: a number (usually on a scale of 3) established by a pathologist to describe the degree of resemblance of the tumor to the surrounding benign tissue.

Invasive tumor: a synonym of cancer. The name refers to invasion of surrounding tissues.

Malignant neoplasm or malignant tumor: synonymous with cancer.

Metastasis: new tumors that appear in the lymph nodes or away from the original tumor.

Neoplasm: the scientific term to describe an abnormal proliferation of genetically altered cells. Neoplasms can be benign or malignant.

Oncogenes: genes that can cause cancer.

Pre-malignancy, pre-cancer or noninvasive tumor: a neoplasm that is not invasive but has the potential to progress to cancer (become invasive) if left untreated.

Prognosis: the probability of cure after the therapy. It is usually expressed as a probability of survival five years after diagnosis. Alternatively, it can be expressed as the number of years when 50% of the patients are still alive. Both numbers are derived from statistics accumulated with hundreds of similar patients to give a Kaplan-Meier curve.

Radiation therapy: using ionizing radiation to kill cancer cells and shrink tumors.

Recurrence: new tumors that appear at the site of the original tumor after surgery.

Remission: a period of time when the cancer is responding to treatment or is under control. Complete remission means that all the signs and symptoms of the disease disappear. Partial remission can describe a tumor that has shrunk but not completely disappeared.

Screening: a test done on healthy people to detect tumors before they become apparent.

Staging: a number (usually on a scale of 4) established by the oncologist to describe the degree of invasion of the body by the tumor.

Surgical excision: the removal of a tumor by a surgeon.

Surgical margins: the evaluation by a pathologist of the edges of the tissue removed by the surgeon to determine if the tumor was removed completely ("negative margins") or if tumor was left behind ("positive margins").

Transformation: the concept that a low-grade tumor transforms to a high-grade tumor over time.

Tumor: any abnormal swelling, lump or mass.

Tumor Suppressor Genes: Genes that stop or suppress cancer growth.