Your Health

Cancer Treatment

The goals of cancer treatment is based on the type and stage of cancer as well as your overall health. General treatment approaches include:
Most treatment plans will include one or more of the following:

Surgery

When possible surgery is used to completely remove a tumor. The surgery is considered curative surgery although it may be done with other treatments like chemotherapy or radiation therapy. It is most successful for solid tumors that have not invaded the surrounding tissues nor spread to other areas of the body. In addition to removing the tumor itself, a surgeon will remove some normal tissue around the tumor called the margin. Lymph nodes associated with that area of the body may also be removed.
It is not always possible to safely remove the entire tumor. Instead, a surgery known as debulking or cytoreductive surgery, may be done to remove as much of the tumor as possible. This can make the tumor more vulnerable to other therapies, such as chemotherapy or radiation. Palliative surgery may also be an option if the cancer has spread. In this case, the surgery may not affect the treatment outcome but rather relieve symptoms like pain or obstructions.

Radiation

Radiation therapy is the use of high energy radiation to destroy cancer cells by damaging cancer DNA. Like surgery, radiation therapy may be used to cure cancer or to relieve symptoms caused by tumors. For example, it is common to use radiation therapy to treat cancer that has spread to the spine. Tumors of the spine can be extremely painful and cause fractures or spinal cord injuries. Radiation can help reduce symptoms and risk of further complications due to tumor growth.
In most cases, the radiation is repeatedly administered from a source outside of the body. Forms of radiation therapy include:
  • External beam therapy —A beam of radiation from a treatment machine is directed to limited parts of the body. The radiation can kill the primary tumor and/or the microscopic tumor deposits in areas near the tumor, such as regional lymph nodes. Stereotactic radiosurgery is a type of external beam therapy that delivers very highly directed high doses of radiation to a very limited area. It is often used for small brain tumors.
  • Brachytherapy or Internal Radiation Therapy —Radioactive material is placed in or near the tumor. This allows higher radiation to be delivered to smaller area of tissue. The radiation may be sealed in a thin wire, catheter, or tube and is often shorter duration than external radiation.
  • Intraoperative radiation therapy is delivered during surgery. The surgeon removes as much of the tumor as possible then a large dose of radiation is given directly to the tumor bed and nearby areas.
  • Photodynamic therapy (PDT) is a treatment option that uses light to damage cancer cells. Photosensitizers, or light-sensitive molecules, are injected into the bloodstream. Some of the molecules are absorbed into healthy cells throughout the body, but most are absorbed by cancer cells. After 24-72 hours the cancer cells are exposed to a specific laser light. The light activates the photosensitizers which damage the cells. This therapy is currently used for superficial cancers like skin cancer.
Hyperthermia is the use of heat to damage cancer cells or make them more sensitive to radiation therapy. It may be delivered locally to the cancer itself or delivered to the entire body if the cancer is widespread.

Chemotherapy

Chemotherapy is the treatment of cancer with drugs that inhibit the growth of cancer cells. Two terms often used to describe chemotherapy are antineoplastic (meaning anticancer) and cytotoxic (cell-killing).
Chemotherapy is used to treat many cancers, either alone or in combination with other treatments. Unlike surgery or radiation, chemotherapy is almost always used as a systemic treatment, meaning the medication travels throughout the body instead of localized to one area. This makes chemotherapy the first choice for cancer that has spread (metastatic) since it can reach cancer cells throughout the body.
More than 100 drugs are currently used for chemotherapy—often in combination—and the list is constantly growing. These medications vary widely in their chemical composition, administration, indications, and side effects. The drugs and combinations are selected to deliver the maximum effect against the cancer without the minimum harm. Great care is generally needed when administering chemotherapy due to the severity of toxic and adverse reactions.

Biologic Therapies

In addition to locating and destroying the bacteria and viruses that make us sick, the immune system is responsible for seeking out and destroying cancer cells before they proliferate. If, for whatever reason, the immune system is unable to successfully clear the body of enemy cancer cells, therapy may still be able to coax the system into battle.
Scientists have developed a class of substances known as biologic response modifiers (BRM). These substances enhance the tumor-destroying capability of the immune system. One of several ways BRMs can accomplish this is by increasing the activity of chemical messengers (cytokines) that stimulate cytotoxic cells to fight. To learn more about specific biologic agents used to treat cancer, see the biologic therapies treatment page.

Hormonal Therapies

The growth of some tumors is stimulated by the presence of hormones. Hormonal therapies block the hormone receptors of certain cancer cells, which prevents hormones from entering the cell. This discourages the cancer cells from growing and dividing.
The anti-estrogen drug tamoxifen is the best example of an effective hormonal therapy for a specific type of breast cancer. Like chemotherapy, hormonal therapies are administered systemically, but are generally better tolerated. To learn more about specific hormonal agents used to treat cancer, see the hormonal therapies treatment page .

Assessing Treatment Effectiveness

The success of cancer treatment can be measured in several ways:
  • Response rates
  • Survival rates
  • Dose-limiting toxicities
Response rates (also called remission rates) indicate the percentage of people whose disease goes into remission after treatment. Response rates can be either partial or complete. A partial response rate indicates a 50% reduction in the size of the primary tumor and no new areas of cancer. A complete response rate is the absence of detectable cancer. Response rates are generally used to describe chemotherapy and hormonal treatments rather than surgery or radiation.
Survival rates are expressed as the percentage of those alive after a designated period of time. In cancer, it is common to measure 5-year-survival rates, which represent the number of people with cancer who are still alive 5 years after diagnosis, regardless of whether or not their cancer persists at that time. While 5-year survival rates are often used to express the effectiveness of treatments, they say nothing about the number of people who are cured permanently of their cancer. They also should not be used to predict an individual person’s prognosis. Five-year survival rates do not necessarily reflect current advances in the treatment of cancer, and they do not always take into account a number of individual factors that can influence survival, such as detection methods, treatment protocols, concurrent illnesses, tumor stage at diagnosis, or personal behaviors, all of which can influence survival rates.
Dose-limiting toxicities are severe adverse effects that preclude the use of higher, more effective doses of chemo- or radiation therapy. For example, the maximum dose of chemotherapy is restricted by the toxic effect it has on bone marrow.

References

A guide to cancer chemotherapy. American Cancer Society website. Available at: http://www.cancer.org/acs/groups/cid/documents/webcontent/003025-pdf.pdf. Accessed May 13, 2015.

A guide to cancer surgery. American Cancer Society website. Available at: http://www.cancer.org/acs/groups/cid/documents/webcontent/003022-pdf.pdf. Accessed May 13, 2015.

Chemotherapy. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/treatment/types/chemotherapy. Updated April 29, 2015. Accessed May 13, 2015.

Modalities of cancer therapy. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/hematology-and-oncology/principles-of-cancer-therapy/modalities-of-cancer-therapy. Updated July 2013. Accessed May 13, 2015.

Radiation therapy. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/treatment/types/radiation-therapy. Updated April 29, 2015. Accessed May 13, 2015.

Surgery. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/treatment/types/surgery. Updated April 29, 2015. Accessed May 13, 2015.

Understanding radiation therapy: A guide for patients and families. American Cancer Society website. Available at:http://www.cancer.org/acs/groups/cid/documents/webcontent/003028-pdf.pdf. Accessed May 13, 2015.

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