CANCER TREATMENT: Radiation Therapy

Therapeutic radiology uses high-energy particles or waves, such as X rays or gamma rays, to focus damaging radiation on the region of a tumor, inflicting genetic damage that kills cancerous cells. Radiation therapy damages rapidly dividing cells, mostly cancer cells but also healthy cells that reproduce quickly. This leads to side effects such as fatigue, skin changes, and loss of appetite.

Other side effects usually are related to the treatment of specific areas, such as hair loss following radiation treatment to the head. Radiation therapy can also cause a decrease in the number of white blood cells, cells that help protect the body against infection. Most side effects are short-lived, as healthy tissues recover from radiation much better than cancer cells because healthy cells repair damaged DNA more efficiently.

Many short doses of radiation therapy, instead of fewer heavier doses, can minimize side effects. The total dose and the number of treatments depend on the size, location, and type of cancer and the patient’s general health. Patients usually receive radiation therapy five days a week for five to eight weeks. Weekend rest breaks allow normal cells to recover.

Unlike surgery, radiation can destroy microscopic cancer cells that have moved into surrounding tissues. Radiation is also a safer option for older patients or those weakened from other diseases, who may not recover well from surgery. Oncologists may use radiation to shrink the tumor, making surgery feasible. For other tumors, radiation may be used following surgery. However, radiation does not always eliminate all tumor cells, and it cannot treat widespread metastases. Like surgery, radiation therapy may be used to relieve pain and discomfort, even when a cure is not likely.

CANCER TREATMENT: Surgery

Oncologists select from a number of options when treating cancer, depending on the type and stage of the tumor involved. The major treatments currently available are surgery, radiation therapy, chemotherapy, hormone therapy, and immunotherapy. Often, targeting cancerous tumors requires the artful combination of more than one type of cancer therapy.

Surgery is the most effective and fastest treatment for tumors that are caught early and have not metastasized. It is the only option ensuring that the entire visible tumor is eliminated. However, there is no guarantee that all microscopic extensions of a tumor have been removed. For this reason, surgeons may also remove a large portion of healthy tissue that surrounds the tumor. This may not be possible if the tumor lies near or within a vital tissue, such as a major nerve or organ.

Often, cancer surgery requires general anesthesia, in which the patient loses consciousness, and a hospital stay of several days. For example, women with breast cancer may have a lumpectomy or mastectomy, surgical removal of part (or all) of the breast. Depending on the stage of the tumor, doctors may also remove the nearby lymph nodes and muscle tissue. As with any major surgery, mastectomies and other major surgical cancer treatments involve some risk, and doctors must consider the overall health of the patient, as well as the stage of the tumor.

Some cancers can be treated surgically with less-invasive techniques, such as laser surgery. Laser surgery uses a powerful beam of high-energy light to vaporize certain tumors of the cervix, larynx, and skin. Physicians perform laser surgery with an endoscope inserted through a small incision in the skin. Laser surgery and other less-invasive surgical procedures may require only local anesthesia, in which a patient loses feeling in one particular area of the body but never loses consciousness.

Sometimes oncologists recommend surgery to improve a patient’s quality of life, even if it is not likely to rid the body of cancer. Surgery of this type aims to correct a problem that is causing discomfort or disability. For example, some cancers may spread to the spine, pressing on the spinal cord or nearby nerves. This pressure may cause severe pain, and in some instances, paralysis. Surgical removal of all or part of the tumor near the spine may alleviate these symptoms.

DIAGNOSA CANCER BY STAGING

In previous writings I wrote an article Diagnosis of Cancer by Detection of Cancer, now I'll write a continuation of the article. When a tumor is detected, the physician takes a biopsy by removing a sample of the tissue. The biopsy sample is inspected under a microscope to determine if the tumor is benign or malignant. Cancerous cells usually appear abnormal in shape and no longer orient themselves in orderly configurations. If the tumor is cancerous, the physician assigns it a stage, indicating how far cancer has spread. The stage is a key factor in determining both the cancer’s treatment and prognosis.

Oncologists, physicians who specialize in the diagnosis and treatment of cancer, use several different staging systems. In one system, tumors are grouped into four stages denoted by Roman numerals I through IV. Stage I cancers are small localized cancers that are usually curable. Stage II and III tumors are usually locally advanced and may or may not have invaded nearby lymph nodes, and stage IV tumors have usually metastasized—that is, spread to distant tissues in the body.

The most widely used staging system is the Tumor, Lymph Node, and Metastasis system, commonly abbreviated TNM. This system uses numbers between zero and three to assess the size of the tumor (T), the extent that it has spread to nearby lymph nodes (N), and the extent that it has spread throughout the body (M). A cancer’s stage depends on a combination of these numbers. For example, a T-1, N-0, and M-0 tumor is a stage 1 tumor. This tumor is 2 cm (1 in) or less (T-1) and has not spread to nearby lymph nodes (accounting for N-0) or metastasized (M-0). The five-year survival rate for a patient with this stage tumor is accordingly excellent. A T-3, N-1, and M-0 tumor is a stage 3 tumor.

This tumor is greater than 5 cm (2 in) and has spread to nearby lymph nodes, but there is no evidence that the cancer has spread to distant tissues. The five-year survival rate for a patient with this tumor is not as high as the T-1, N-0, M-0 patient. Stage 4 tumors are distinguished by an M-1 number. This means they have progressed to the point where metastasis is widespread, and the prognosis is usually quite poor.

HOW CAN CANCER DEVELOP IN OUR BODY: CELLS BREAK FREE AND SPREAD

More cancer, more cancer again, the reader may get bored with this article, but this information must I provide to be a lesson for us. Cancer can develop in the human body, therefore I think we need to know how the cancer can develop in the body. This article is a continuation of previous articles that discuss the same topic. Evading the many obstacles that guard against runaway cell division is still not enough for cancer to develop. A malfunctioning cell must also skirt a number of safety mechanisms designed to prevent cells from growing where they are not supposed to in the body.

Normal cells adhere to each other and to a fibrous meshwork called an extracellular matrix. This matrix exists throughout all tissues and provides the structural support on which cells grow and form organs and other complex tissues. While a normal cell will often die if it cannot adhere to an extracellular matrix, cancer cells survive without this matrix.

1. Tumor Forms

A tumor is a mass of cells not dependent upon an extracellular matrix. These cells can grow on top of each other, creating a mass of abnormal cells. Often a tumor develops its own network of tiny blood vessels to supply itself with nutrient-rich blood, a process called angiogenesis.

There are two general types of tumors. Benign tumors do not invade other tissues and are limited to one site, making surgical removal possible and the odds for a full recovery excellent. Some benign tumors are quite harmless and are not surgically removed unless they are unsightly or uncomfortable. For example, warts are benign tumors of the outer layer of the skin. Although they are usually not dangerous, warts may cause discomfort. Other benign tumors are thought to be precursors to cancerous, or malignant, tumors.

2. Tumors Spread

Tumors are malignant only if they can invade other parts of the body. Malignant tumors extend into neighboring tissue or travel to distant sites, forming secondary growths known as metastases. To metastasize, tumor cells break through a nearby blood vessel to enter the circulatory system or through a lymphatic vessel wall to enter the lymphatic system. Most metastases occur in organs that are the next site downstream in the circulatory system or the lymphatic system and contain a network of capillaries, or small blood vessels. For example, cancer of the large intestine often travels through the bloodstream to the liver, the organ immediately downstream from the intestines.
In the lymphatic system, tumor cells can spread to surrounding lymph nodes, or lymph glands. Normally, lymph nodes filter out and destroy infectious materials circulating in the lymphatic system.
The unique receptors on the surface of a cell may also play a role in where tumors metastasize. Specialized molecules on a cell’s surface identify where in the body the cell belongs. Similar cells adhere to one another when their surface receptors are compatible. Most often cells from different tissues and organs have incompatible surface receptors.

However, some tissue types share similar surface receptors, enabling cancerous cells to move between them and proliferate. Prostate cells and bone cells, for example, have similar surface receptors. This gives prostate cancer cells a natural affinity for bone tissue, where they can settle to form a new tumor.

Many cancers shed cells into the bloodstream early in their growth. Most of these cells die in the bloodstream, but some lodge against the surface of the blood vessel walls, eventually breaking through them and into adjacent tissue.

In some cases, these cells survive and grow into a tumor. Others may divide only a few times, forming a small nest of cells that remain dormant as a micrometastasis. They may remain dormant for many years, only to grow again for reasons not yet known.