Chemotherapy: Drug treatment uses chemicals to kill cancer cells

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Chemotherapy: Drug treatment uses chemicals to kill cancer cells

Chemotherapy — Learn how this cancer treatment works and what the potential side effects are.

Chemotherapy — the use of medications to treat cancer — has played a major role in cancer treatment for half a century. Years of testing and research have proved chemotherapy to be an effective cancer treatment. It may be your only treatment, or it may be used in combination with other treatments, such as surgery and radiation therapy.

Chemotherapy works by killing rapidly dividing cells. These cells include cancer cells, which continuously divide to form more cells, and healthy cells that also divide quickly, such as those in your bone marrow, gastrointestinal tract, reproductive system and hair follicles. Healthy cells usually recover shortly after chemotherapy is complete, so for example, your hair starts growing again.

Causes

Invasive lobular carcinoma starts when cells in one or more milk-producing glands of the breast start growing abnormally. The cells divide more rapidly than normal cells do. When these abnormal cells stay within the lobule, the condition is referred to as lobular carcinoma in situ (LCIS) and is considered a marker for increased risk of breast cancer. At some point, abnormal cells may break out of the lobules and invade or "infiltrate" the surrounding tissue, becoming ILC.

About half the lobular breast cancers involve alterations (mutations) in a gene called E-cadherin (CDH1). This gene controls the activity of a protein that helps keep tumor cells from invading normal tissue and spreading. Some scientists believe that the turning off of E-cadherin sets the stage for ILC to develop. When lobular carcinoma is diagnosed, a laboratory doctor (pathologist) may order an E-cadherin protein study on the tissue to help differentiate ILC from LCIS.

Risk factors

A risk factor is anything that makes it more likely you'll get a particular disease. But having one or even several risk factors doesn't mean you'll get cancer.

  • Your gender. Being female is the single most significant risk factor for any type of breast cancer.
  • Lobular carcinoma in situ. Women with LCIS — abnormal cells within breast lobules — face a higher risk of developing invasive cancer later, in either breast. LCIS is a marker indicating an increased risk of developing breast cancer but it's not a cancer in itself.
  • Older age. Women diagnosed with ILC typically are older than those with invasive ductal carcinoma (IDC). The median age at diagnosis for ILC is in the early 60s, compared with the mid- to late 50s for IDC.
  • Postmenopausal hormone use. Use of the female hormones estrogen and progesterone during and after menopause has been shown to increase the risk of ILC. Researchers believe the hormones may stimulate tumor growth and also make tumors more difficult to see on mammograms. Although studies in the 1990s found a correlation between rising rates of ILC and use of hormone therapy, newer hormone regimens, including lower dose combinations, haven't been assessed.
  • Genetic cancer susceptibility. Women with a rare inherited condition called hereditary diffuse gastric cancer syndrome have an increased risk of getting both stomach (gastric) cancer and lobular breast cancer. Women with this condition run a 20 percent to 40 percent risk of developing lobular breast cancer during their life.

Tests and diagnosis

Early diagnosis of ILC can be challenging. A mammogram, which takes X-ray images of your breast tissue, may not detect ILC early in the cancer's development.

Your doctor may use a mammogram or a breast ultrasound (ultrasonography) to evaluate an abnormality found during a physical exam or seen on a screening mammogram. Ultrasound uses sound waves to produce images of structures deep within the body. Ultrasound tends to be better than mammography at detecting ILC, but may also underestimate the size of the tumor.

At the time of diagnosis and before surgery, your doctor may order magnetic resonance imaging (MRI) of the breast to evaluate the extent of the breast cancer and help with surgical management decisions. Breast MRI uses a magnet and radio waves to take pictures of the breast's interior.

The diagnosis of ILC can only be made by biopsy — removing samples of breast tissue for analysis in the laboratory. If the biopsy results confirm that you have ILC, the next step is to determine how advanced your cancer is — its stage, or extent and severity.

Cancer cells removed in a biopsy will also be tested for the presence or absence of receptors for estrogen and progesterone. ILC is almost always estrogen receptor positive, which means it may be treated with drugs that alter hormone interactions with the cancer cells.

Treatments and drugs

Treatment of ILC consists of surgery and additional (adjuvant) therapy, which may include chemotherapy, radiation and hormone therapy. At the time of the breast cancer surgery, the lymph nodes under your arm are also evaluated using the sentinel node technique. The sentinel lymph nodes are the first lymph nodes to receive drainage from breast tumors, and if they test negative for cancer cells, the cancer likely hasn't spread outside the breast. If the sentinel lymph nodes are positive for cancer, then the surgeon will discuss removing additional lymph nodes, a procedure known as an axillary node dissection.

If the tumor is large relative to the size of your breast and you're hoping to have breast-sparing surgery, your surgeon may recommend chemotherapy before surgery (neoadjuvant chemotherapy) to shrink the tumor. After you've completed this initial chemotherapy, your surgeon will then decide if breast-conserving surgery is an option.

Surgery
It's sometimes possible to remove early-stage ILC with a breast-sparing operation known as lumpectomy or wide local excision. The surgeon will remove the tumor itself, as well as a margin of normal tissue surrounding the tumor to make sure all the cancer that can be removed is taken out. Negative or "clean" margins reduce the chance of leaving any cancer in the breast. If the margins are positive, you may need additional surgery until negative margins are achieved, or the surgeon may decide to perform a mastectomy.

Chemotherapy
Chemotherapy uses drugs to destroy cancer cells. Treatment often involves receiving two or more drugs in different combinations. You may have four to eight treatments or "cycles" spread over three to six months.

Radiation
After a lumpectomy, a course of radiation therapy is given to kill any remaining cancer cells in the breast and under your arm. This can help decrease the chance of cancer coming back in the area. Radiation typically involves about 30 treatments over six weeks and begins about three to four weeks after the lumpectomy. If chemotherapy is recommended, you will receive the chemotherapy treatment first, followed by radiation therapy.

Hormone therapy
Hormone therapy — or more accurately, hormone-blocking therapy — is commonly used to treat ILC when the tumor tests positive for estrogen receptors. Two classes of medications are used in hormone therapy: selective estrogen receptor modulators (SERMs), such as tamoxifen; and aromatase inhibitors, such as anastrozole (Arimidex), letrozole (Femara) or exemestane (Aromasin).

Last Updated: 03/29/2007
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