Understanding Cancer 

If you or a loved one has been diagnosed with cancer, you may be overwhelmed and unsure what to do. Treatment, you might feel, is in the hands of medical professionals, leaving you with little control over your life and health. At Geisinger, you and your family are active participants in understanding the nature of your diagnosis and developing a treatment plan. 

Cancer does not appear overnight and will not be treated overnight. You have time to research your cancer diagnosis in the Geisinger Community Health Library, which provides information on types of cancer, treatments and studies. This information allows you to participate in discussions with your Geisinger team of physicians to determine the best treatment. Talk openly with your physician. Ask questions.

Questions you may want to ask your physician:

• What tests or procedures will I need?
• When will we know my prognosis?
• What are my treatment options?
• What are side-effects of treatments?
• How long will treatment last? When will it start?
• Where and how often will treatment occur?
• Will clinical trials benefit me?
• Can I keep working?
• Will my appearance change?

What is Cancer?

Cancer is a renegade system of growth that originates within a patient's body. There are many different types of cancers, but all share one identifying characteristic: unchecked growth that progresses toward limitless expansion. It is difficult to imagine anyone who has not heard of this illness. Most people have been affected because either they or their loved ones or friends are cancer survivors.

Cancer can originate almost anywhere in the body. The national cancer institute identifies the four basic types of cancer as:

Carcinomas - the most common types of cancer, arise from the cells that cover external and internal body surfaces. Lung, breast, and colon are the most frequent cancers of this type in the United States.

Sarcomas - cancers arising from cells found in the supporting tissues of the body such as bone, cartilage, fat, connective tissue, and muscle.

Lymphomas - cancers that arise in the lymph nodes and tissues of the body's immune system.

Leukemias - cancers of the immature blood cells that grow in the bone marrow and tend to accumulate in large numbers in the bloodstream.

Not all tumors are cancerous. There are two different types of tumors: Malignant and Benign. 

• Benign tumors aren't cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.
• Malignant tumors are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis.

A malignant tumor is a more serious health problem than a benign tumor because cancer cells can spread to distant parts of the body. For example, a melanoma (a cancer of pigmented cells) arising in the skin can have cells that enter the bloodstream and spread to distant organs such as the liver or brain.

Cancer cells in the liver would be called metastatic melanoma, not liver cancer. Metastases share the name of the original ("primary") tumor. Melanoma cells growing in the brain or liver can disrupt the functions of these vital organs and are potentially life threatening.

How is Cancer Diagnosed?

Diagnosing cancer involves the use of a variety of tests that provide details about abnormal cells, which may have been detected through routine medical examinations, self-examination, or reported symptoms. More information about these cells must be gathered in order to identify them as malignant (cancerous) or non-malignant (non-cancerous), and if they are malignant, to determine how serious (aggressive) the particular cancer cells are. Aggressive cancers grow and spread more quickly than less-aggressive or “indolent” cancers. There are many types of tests specifically designed to evaluate cancer:

• A pathology report is based on observation of abnormal cells under a microscope.
• Diagnostic imaging involves visualization of abnormal masses using high tech machines that create images, such as x-rays, computed tomography (CT), positron emission test (PET), magnetic resonance imaging (MRI), and combined PET/CT.
• Blood tests measure substances in the blood that may indicate how advanced the cancer is or other problems related to the cancer.
• Tumor marker tests detect substances in blood, urine, or other tissues that occur in higher than normal levels with certain cancers.
• Special laboratory evaluation of DNA involves the identification of the genetic make-up—the DNA—of the abnormal cells.

Cancer Staging
Cancer staging systems describe how far cancer has spread anatomically and attempt to put patients with similar prognosis and treatment in the same staging group. Since prognosis and treatment depend quite a bit on the stage, you can see how important it is to know what stage you have! At the same time other factors, including your general health, your own preference, and the results of biochemical tests on your cancer cells will contribute to determining the prognosis and treatment. So while the stage is important it is not everything.

The concept of stage is applicable to almost all cancers except for most forms of leukemia. Since leukemias involve all of the blood, they are not anatomically localized like other cancers, so the concept of staging doesn't make as much sense for them. A few forms of leukemia do have staging systems which reflect various measures of how advanced the disease is. For most solid tumors, there are two related cancer staging systems, the Overall Stage Grouping, and the TNM system.

Roman Numeral Staging
In this system, cases are grouped into four stages denoted by Roman numerals I through IV, or are classified as "recurrent." In general, stage I cancers are small localized cancers that are usually curable, while stage IV usually represents inoperable or metastatic cancer. Stage II and III cancers are usually locally advanced and/or with involvement of local lymph nodes. Actually, these stages are defined precisely, but the definition is different for each kind of cancer. In addition, it is important to realize that the prognosis for a given stage also depends on what kind of cancer it is, so that a stage II non small cell lung cancer has a different prognosis from a stage II cervical cancer.

Unfortunately, it is common for cancer to return months or years after the primary tumor has been removed because cancer cells had already broken away and lodged in distant locations by the time the primary tumor was discovered, but had not formed tumors which were large enough to detect at that time. Sometimes a tiny bit of the primary tumor was left behind in the initial surgery and this later grows into a macroscopic tumor. Cancer that recurs after all visible tumor has been eradicated, is called recurrent disease. Disease that recurs in the area of the primary tumor is locally recurrent, and disease that recurs as metastases is referred to as a distant recurrence. Distant recurrence is usually treated similarly to stage IV disease (sometimes the terms are used interchangeably) and anyone in this situation should investigate options for both stage IV and recurrent disease. The significance of a Local recurrence may be quite different than distant recurrence, depending on the type of cancer.

TNM Staging
In the TNM system, TNM stands for Tumor, Nodes, and Metastases. Each of these is categorized separately and classified with a number to give the total stage. Thus a T1N1M0 cancer means the patient has a T1 tumor, N1 lymph node involvement, and no distant metastases. Of course the definitions of T, N and M are specific to each cancer, but it is possible to give a general idea of what they mean.

T: Tumor - T Classifies the extent of the primary tumor, and is normally given as T0 through T4. T0 represents a tumor that has not even started to invade the local tissues. This is called "In Situ". T4 on the other hand represents a large primary tumor that has probably invaded other organs by direct extension, and which is usually inoperable.

N: Lymph Nodes - N classifies the amount of regional lymph node involvement. It is important to understand that only the lymph nodes draining the area of the primary tumor are considered in this classification. Involvement of distant lymph nodes is considered to be metastatic disease. The definition of just which lymph nodes are regional depends on the type of cancer. N0 means no lymph node involvement while N4 means extensive involvement. In general more extensive involvement means some combination of more nodes involved, greater enlargement of the involved nodes, and more distant (But still regional) node involvement.

M: Metastasis - M is either M0 if there are no metastases or M1 if there are metastases.
As with the other system, the exact definitions for T and N are different for each different kind of cancer.

As you can see, the TNM system is more precise than the I through IV system and certainly has a lot more categories. The two systems are actually related. The I through IV groupings are actually defined using the TNM system. For example, stage II non-small cell lung cancer means a T1 or T2 primary tumor with N1 lymph node involvement, and no metastases (M0).

How does Diagnosis Determine Treatment?
Historically, a combination of pathological assessment (laboratory evaluation using a microscope) and diagnostic imaging has been used to identify the type of cancer and its stage, and then the treatment. Stage indicates how extensive the cancer is and how much it has spread. Staging usually involves determining the size of the primary tumor and evaluating whether it has remained in the tissue in which it started, whether it has invaded other nearby organs or tissues, and whether cancer cells have spread to distant locations in the body. The cancer is then assigned a stage on a predetermined scale of numbers and letters, for example stage I, II, IIIa, IIIb, IV, etc. The higher number and letter combination indicates more extensive spread, and therefore a more serious condition. Treatment is often selected based on the stage of disease. Higher stage cancers typically receive very aggressive treatments and lower stage disease less aggressive treatment.

However, research has indicated that identifying the stage of disease may not be the most accurate technique for determining how aggressive it is. For example, some early stage diseases may recur or progress even after treatment, while some late stage cancers may stay in remission. These findings suggest that there may be factors other than how the cancer looks under a microscope and how far it has spread at the time of diagnosis that may better indicate the likelihood that a given cancer will recur and/or progress.

Human genomics, which is the study of the entire genetic material of humans, has provided invaluable tools for identifying the genetic components of cancers. The mapping of the human genome, which consists of 30,000 to 70,000 genes, has laid the ground work for understanding the role those genes play in human health and disease. Cancer is many different diseases; however, one aspect of all cancers that is similar is damage to the DNA resulting in uncontrolled cell growth. Identifying the genes for each cancer type that are involved in the capacity grow and spread may provide valuable prognostic information.

As improvements are made in the special laboratory techniques used to identify the genetic make-up of cancers, this genetic information may become a better predictor of cancer aggressiveness and outcome than stage, which has been the diagnostic indicator of choice in the past. Additionally, this genetic information will likely play an increasing role in directing treatment. Specifically, the genes involved in each cancer may indicate more aggressive treatment for some cancers and less aggressive treatment for others.

Cancer Treatments

What treatment is best for you? Which methods have proven to be most effective? Here you can find answers to your questions, plus learn about what to ask your physician, what's new in research, and what you can expect after treatment is over. 

Chemotherapy
Chemotherapy, in its most general sense, is the treatment of disease by chemicals especially by killing micro-organisms or cancerous cells.  There are many different types of chemotherapy.  To learn more about the different kinds of chemotherapy, visit our Understanding Chemotherapy webpage.

Radiation Therapy
Radiation therapy (also called radiotherapy, X-ray therapy, or irradiation) is the use of a certain type of energy (called ionizing radiation) to kill cancer cells and shrink tumors. 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. To learn more about the different types of radiation therapy, visit our Understanding Radiation Therapy webpage.

Other Types of Treatment 
 

• Surgery
• Targeted Therapy
• Immunotherapy
• Photodynamic Therapy 
• Antiangiogenesis Therapy
• Hyperthermia
• Bone Marrow and Peripheral Blood Stem Cell Transplantation
• Gene Therapy: Questions and Answers
• Complementary and Alternative Medicine

more

National Cancer Institute website