A tumor is an abnormal growth caused by the uncontrolled division of cells. Benign tumors do not have the potential to spread to other parts of the body (a process called metastasis) and are curable by surgical removal. Malignant or cancerous tumors, however, may metastasize to other parts of the body and will ultimately result in death if not successfully treated by surgery and/or other methods.
Surgical removal is one of four main ways that tumors are treated. Chemotherapy, radiation therapy, and biological therapy are other treatment options. There are a number of factors used to determine which methods will best treat a tumor. Because benign tumors do not have the potential to metastasize, they are often treated successfully with surgical removal alone. Malignant tumors, however, are most often treated with a combination of surgery and chemotherapy and/or radiation therapy (in about 55% of cases). In some instances, non-curative surgery may make other treatments more effective. Debulking a cancer—making it smaller by surgical removal of a large part of it—is thought to make radiation and chemotherapy more effective.
Surgery is often used to accurately assess the nature and extent of a cancer. Most cancers cannot be adequately identified without examining a sample of the abnormal tissue under a microscope. Such tissue samples are procured during a surgical procedure. Surgery may also be used to determine exactly how far a tumor has spread.
There are a few standard methods of comparing one cancer to another for the purposes of determining appropriate treatments and estimating outcomes. These methods are referred to as staging. The most commonly used method is the TNM system.
- "T" stands for tumor and reflects the size of the tumor.
- "N" represents the spread of the cancer to lymph nodes , largely determined by those nodes removed at surgery that contain cancer cells. Since cancers spread mostly through the lymphatic system, this is a useful measure of a cancerís ability to disperse.
- "M" refers to metastasis and indicates if metastases are present and how far they are from the original cancer.
Staging is particularly important with such lymphomas as Hodgkin's disease, which may appear in many places in the lymphatic system. Surgery is a useful tool for staging such cancers and can increase the chance of a successful cure, since radiation treatment is often curative if all the cancerous sites are located and irradiated.
The American Cancer Society estimates that approximately one million cases of cancer are diagnosed in the United States each year. Seventy-seven percent of cancers are diagnosed in men and women over the age of 55, although cancer may affect individuals of any age. Men develop cancer more often than women; one in two men will be diagnosed with cancer during his lifetime, compared to one in three women. Cancer affects individuals of all races and ethnicities, although incidence may differ among these groups by cancer type.
Surgery may be used to remove tumors for diagnostic or therapeutic purposes.
Diagnostic tumor removal
A biopsy is a medical procedure that obtains a small piece of tissue for diagnostic testing. The sample is examined under a microscope by a doctor who specializes in the effects of disease on body tissues (a pathologist) to detect any abnormalities. A definitive diagnosis of cancer cannot be made unless a sample of the abnormal tissue is examined histologically (under a microscope).
There are four main biopsy techniques used to diagnose cancer. These include:
- Aspiration biopsy. A needle is inserted into the tumor and a sample is withdrawn. This procedure may be performed under local anesthesia or with no anesthesia at all.
- Needle biopsy. A special cutting needle is inserted into the core of the tumor and a core sample is cut out. Local anesthesia is most often administered.
- Incisional biopsy. A portion of a large tumor is removed, usually under local anesthesia in an outpatient setting.
- Excisional biopsy. An entire cancerous lesion is removed along with surrounding normal tissue (called a clear margin). Local or general anesthesia may be used.
Therapeutic tumor removal
Once surgical removal has been decided, a surgical oncologist will remove the entire tumor, taking with it a large section of the surrounding normal tissue. The healthy tissue is removed to minimize the risk that abnormal tissue is left behind.
When surgical removal of a tumor is unacceptable as a sole treatment, a portion of the tumor is removed to debulk the mass; this is called cytoreduction. Cytoreductive surgery aids radiation and chemotherapy treatments by increasing the sensitivity of the tumor and decreasing the number of necessary treatment cycles.
In some instances the purpose of tumor removal is not to cure the cancer, but to relieve the symptoms of a patient who cannot be cured. This approach is called palliative surgery. For example, a patient with advanced cancer may have a tumor causing significant pain or bleeding; in such a case, the tumor may be removed to ease the patient's pain or other symptoms even though a cure is not possible.
The surgical removal of malignant tumors demands special considerations. There is a danger of spreading cancerous cells during the process of removing abnormal tissue (called seeding). Presuming that cancer cells can implant elsewhere in the body, the surgeon must minimize the dissemination of cells throughout the operating field or into the blood stream.
Special techniques called block resection and no-touch are used. Block resection involves taking the entire specimen out as a single piece. The no-touch technique involves removing a specimen by handling only the normal tissue surrounding it; the cancer itself is never touched. These approaches prevent the spread of cancer cells into the general circulation. Pains are taken to clamp off the blood supply first, preventing cells from leaving by that route later in the surgery.
A tumor may first be palpated (felt) by the patient or by a health care professional during a physical examination . A tumor may be visible on the skin or protrude outward from the body. Still other tumors are not evident until their presence begins to cause such symptoms as weight loss, fatigue, or pain. In some instances, tumors are located during routine tests (e.g. a yearly mammogram or Pap test).
Retesting and periodical examinations are necessary to ensure that a tumor has not returned or metastasized after total removal.
Each tumor removal surgery carries certain risks that are inherent to the procedure. There is always a risk of misdiagnosing a cancer if an inadequate sample was procured during biopsy, or if the tumor was not properly located. There is a chance of infection of the surgical site, excessive bleeding, or injury to adjacent tissues. The possibility of metastasis and seeding are risks that have to be considered in consultation with an oncologist.
The results of a tumor removal procedure depend on the type of tumor and the purpose of the treatment. Most benign tumors can be removed successfully with no risk of the abnormal cells spreading to other parts of the body and little risk of the tumor returning. Malignant tumors are considered successfully removed if the entire tumor can be removed, if a clear margin of healthy tissue is removed with the tumor, and if there is no evidence of metastasis. The normal results of palliative tumor removal are a reduction in the patient's symptoms with no impact on survival.
Morbidity and mortality rates
The recurrence rates of benign and malignant tumors after removal depend on the type of tumor and its location. The rate of complications associated with tumor removal surgery differs by procedure, but is generally very low.
If a benign tumor shows no indication of harming nearby tissues and is not causing the patient any symptoms, surgery may not be required to remove it. Chemotherapy, radiation therapy, and biological therapy are treatments that may be used alone or in conjunction with surgery.
Abeloff, Martin D., James O. Armitage, Allen S. Lichter, and John E. Niederhuber. "Cancer Management." Clinical Oncology , 2nd ed. Philadelphia, PA: Churchill Livingstone, Inc., 2000.
"Principles of Cancer Therapy: Surgery." Section 11, Chapter 144 in The Merck Manual of Diagnosis and Therapy , edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.
American Cancer Society. 1599 Clifton Rd. NE, Atlanta, GA 30329-4251. (800) 227-2345. http://www.cancer.org .
National Cancer Institute (NCI). NCI Public Inquiries Office, Suite 3036A, 6116 Executive Boulevard, MSC8332, Bethesda, MD 20892-8322. (800) 4-CANCER or (800) 332-8615 (TTY). http://www.nci.nih.gov .
Society of Surgical Oncologists. 85 West Algonquin Rd., Suite 550, Arlington Heights, IL 60005. (847) 427-1400. http://www.surgonc.org .
American Cancer Society. All About Cancer: Detailed Guide , 2003 [cited April 9, 2003]. http://www.cancer.org/docroot/CRI/CRI_2_3.asp .
J. Ricker Polsdorfer, MD Stephanie Dionne Sherk
WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?
Tumors are usually removed by a general surgeon or surgical oncologist. The procedure is frequently done in a hospital setting, but specialized outpatient facilities may sometimes be used.
QUESTIONS TO ASK THE DOCTOR
- What type of tumor do I have and where is it located?
- What procedure will be used to remove the tumor?
- Is there evidence that the tumor has metastasized?
- What diagnostic tests will be performed prior to tumor removal?
- What method of anesthesia/pain relief will be used during the procedure?