Surgery — an operation to repair or remove part of your body to diagnose or treat a condition — remains the foundation of cancer treatment. Your doctor may use surgery to achieve any number of goals, from diagnosing your cancer to treating it. It may be your only cancer treatment, or it may be supplemented with other treatments, such as radiation and chemotherapy.

The prospect of surgery may make you feel anxious. But knowing more about why and how surgery is used and what to expect can help you feel more at ease with your treatment.

As it relates to cancer, surgery may be used to achieve one or more goals. Common reasons surgery might be used include:

• Cancer prevention. In some cases, if your doctor suspects you'll develop cancer in certain tissues or organs, he or she may recommend removal of those tissues or organs. For example, your doctor may remove colon and rectal (colorectal) polyps — raised clumps of cells occurring as a result of abnormal cell growth — from the inner lining of your colon and rectal wall. Not all polyps become cancerous, but nearly all colorectal cancers evolve from polyps.
• Diagnosis and staging. Your doctor may surgically remove (biopsy) all or part of a tumor — allowing the tumor to be studied under a microscope — to determine whether the growth is cancerous (malignant) or noncancerous (benign). If it's cancerous, surgery helps to define how advanced the cancer is (staging) by enabling your doctor to look at the size of the tumor, to determine whether it's all been removed and to see if it's traveled to your lymph nodes. Additional tests may be needed to completely define the stage of disease, but by determining the stage of the cancer, your doctor can better suggest what your best treatment course might be.
• Primary treatment. Surgery is most successful if cancer is localized and hasn't spread. If your doctor believes your cancer hasn't spread, he or she may recommend surgery to remove the cancerous tumor as your primary treatment. Sometimes your doctor may also recommend chemotherapy or radiation therapy before surgery (neoadjuvant therapy) or after surgery (adjuvant therapy). These therapies are distinct from your primary treatment. Neoadjuvant therapy can help shrink a tumor before surgery, making the operation easier. Adjuvant therapy targets cancer cells that may have come from the original tumor and spread before the operation, and may decrease your chances of a recurrence of the cancer.
• Debulking. When it's not possible to remove all of a cancerous tumor — for example, because doing so may severely harm an organ — your doctor may remove as much as possible (debulking) in order to make chemotherapy or radiation more effective.
• Relieving symptoms or side effects. Sometimes surgery is used to improve your quality of life rather than treat the cancer itself — for example, to relieve pain caused by a tumor that's pressing on a nerve or bone. Another example might include removing a tumor that's obstructing your intestine.

Many types of surgical techniques exist. The appropriate type of operation for you depends on the goal of the operation and on your specific condition.

A tissue biopsy — removal of a sample of tissue for study under a microscope — is almost always necessary to make a diagnosis of cancer. Several techniques for obtaining tissue samples are available. These include:

• Needle biopsy. Your doctor uses a thin needle and a syringe to remove small pieces of tissue from a tumor. Two types of needle biopsy exist — fine-needle aspiration and core biopsy. These procedures are essentially the same, but a core biopsy involves using a slightly larger needle to remove a small, solid core of tissue.

• Endoscopic biopsy. Your doctor inserts a thin, flexible tube (endoscope) into a natural opening in your body, such as your rectum or mouth. The endoscope contains a fiber-optic light and a video camera at its tip. The camera lens transmits images to an external monitor so that your doctor can look closely at areas inside your body. If the doctor sees abnormal looking tissue, he or she can insert instruments through the endoscope to remove or sample tissue. You may need a local anesthetic to numb a specific area of your body, a sedative or both.

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• Endoscopy

• Surgical biopsy. Your doctor makes an incision through your skin and removes either an entire tumor (excisional biopsy) or a portion of a tumor (incisional biopsy). In some cases, you may need only local anesthesia, such as when the lesion is on the surface of your skin (superficial). Other times, your doctor may use general anesthesia.

• Laparoscopy. During laparoscopy, an incision is made in your abdominal wall and the laparoscope — an instrument similar to an endoscope — is inserted to look for cancer. This can also be done inside your chest (thoracoscopy or mediastinoscopy).

In some cases, your doctor may need to do a further, more invasive exploration. He or she may conduct open surgery in which a longer incision is made in your abdomen (laparotomy) or your chest (thoracotomy or mediastinotomy), allowing your doctor to directly view and evaluate those areas.

The primary purpose of surgical therapy is to cure your cancer by physically removing all of it from your body. The surgeon usually does this by cutting into your body and removing the cancer along with some extra surrounding tissue to ensure that all of the cancer is removed. Your surgeon may also remove some lymph nodes in the area to determine if the cancer has spread. This helps your doctor assess the chance of your being cured, as well as the need for any further therapy.

Many types of surgical methods for treating cancer and precancerous conditions exist, and investigators are always researching new methods. But several common types of surgical treatment include:

• Traditional surgery. In a "traditional" operation, your doctor attempts to completely remove the cancer by using a scalpel, scissors or both. This might include removing the cancer itself, a surrounding margin of tissue, lymph nodes or all of these. For example, in the case of breast cancer, your doctor may remove the breast cancer by removing the whole breast (mastectomy) or by removing the cancer and some of the surrounding tissue. Or in the case of lung cancer, your doctor may remove one lobe of the lung or the entire lung.

• Cryosurgery. During this type of surgery, your doctor uses very cold material, such as liquid nitrogen spray or a cold probe, to freeze and destroy cells that may become cancerous, such as irregular cells in the cervix.

• Electrosurgery. By applying high-frequency electrical currents, your doctor can kill cancer cells, for example, in your mouth or on your skin.

• Laser surgery. Laser surgery, used to treat many types of cancer, uses beams of high-intensity light to shrink or vaporize cancer cells. In some cases, the heat of the laser accomplishes this. In other cases, the laser is used to activate a previously administered chemical that cancer cells absorb. When stimulated by light, the chemical kills the cancer cells.

• Mohs' surgery. Useful for removing cancer from sensitive areas such as near the eye and for assessing how deep a cancer goes, this method of surgery involves carefully removing cancer layer by layer with a scalpel. After removing a layer, your doctor evaluates it under a microscope, continuing in this manner until all the abnormal cells have been removed and the margin tissue shows no evidence of cancer.

Not all operations are the same, but in general, you can expect certain similarities. These include:

• Preparation. In general, expect to undergo certain tests, such as blood tests, urine tests, X-rays and other imaging tests, in the days preceding your surgery. These tests will help your doctor assess your surgical needs, such as your blood type should you need a transfusion, and identify potential risks, such as infections, that may influence your surgery. You may also be asked to avoid eating or drinking from the evening before the surgery until the operation is complete.

• Anesthesia. If you're having surgery, you'll likely need some type of anesthesia — medications that block the sensation of pain. In some cases, such as operations or biopsies near the surface of your skin, you may remain awake and need only local anesthesia, which is injected or applied to the area involved. Regional anesthesia or nerve blocks — often injected near nerves of your spinal cord or around other nerves in your body — anesthetize a larger area than does local anesthesia. You also remain awake during this type of procedure. For other major surgery, you'll often need general anesthesia, which puts you to sleep. You typically receive general anesthesia by breathing in the medication through a face mask or by injection of it into a vein in your arm. If receiving regional or general anesthesia, you'll be monitored closely after surgery until the anesthesia wears off. This could take several hours.

• After the surgery. Depending on what type of surgery you have, you may stay in the hospital for a time before being sent home. Your doctor will give you specific directions for your recovery, such as how to care for any wounds, what foods or activities to avoid and what medications to take. You may also experience certain side effects. Pain is a common side effect of most operations. Some cause more pain than others do. Your doctor will tell you how to keep your pain to a minimum and will provide medications to reduce or eliminate the pain. You also face the possibility of complications, such as an infection occurring at the site of the wound. If this happens, your doctor will likely prescribe antibiotics to treat the infection. Though not common, other more serious complications requiring medical attention may occur. These include other internal infections, pneumonia, internal or external bleeding, blood clots and problems regaining certain body functions, such as bowel movements.

Whatever treatment your doctor recommends, you're likely to feel some anxiety about your condition and the treatment process. Knowing what to expect can help. Use this information to help you talk with your doctor and ask informed questions.