Breast Cancer Detection

High-quality mammography is the most effective technology presently available for breast cancer screening. Efforts to improve mammography focus on refining the technology and improving how it is administered and x-ray films are interpreted. NCI is funding research to reduce the already low radiation dosage of mammography; enhance mammogram image quality; develop statistical techniques for computer-assisted interpretation of images; enable long-distance, electronic image transmission technology (telemammography/teleradiology) for clinical consultations; and improve image-guided techniques to assist with breast biopsies. (A breast biopsy is the removal of cells or tissues to look at under a microscope to check for signs of disease). NCI also supports research on technologies that do not use x-rays, such as magnetic resonance imaging (MRI), ultrasound, and breast-specific positron emission tomography (PET) to detect breast cancer. The following information describes the latest imaging techniques that are in use or being studied.

Ultrasound

Ultrasound, also called sonography, is an imaging technique in which high-frequency sound waves that cannot be heard by humans are bounced off tissues and internal organs. Their echoes produce a picture called a sonogram. Ultrasound imaging of the breast is used to distinguish between solid tumors and fluid-filled cysts. Ultrasound can also be used to evaluate lumps that are hard to see on a mammogram. Sometimes, ultrasound is used as part of other diagnostic procedures, such as fine needle aspiration (also called needle biopsy). Fine needle aspiration is the removal of tissue or fluid with a needle for examination under a microscope to check for signs of disease.

During an ultrasound examination, the clinician spreads a thin coating of lubricating jelly over the area to be imaged to improve conduction of the sound waves. A hand-held device called a transducer directs the sound waves through the skin toward specific tissues. As the sound waves are reflected back from the tissues within the breast, the patterns formed by the waves create a two-dimensional image of the breast on a computer.

Ultrasound is not used for routine breast cancer screening because it does not consistently detect certain early signs of cancer such as microcalcifications (tiny deposits of calcium in the breast that cannot be felt but can be seen on a conventional mammogram). A cluster of microcalcifications may indicate that cancer is present.

Digital Mammography

Digital mammography is a technique for recording x-ray images in computer code instead of on x-ray film, as with conventional mammography. The images are displayed on a computer monitor and can be enhanced (lightened or darkened) before they are printed on film. Images can also be manipulated; the radiologist (a doctor who specializes in creating and interpreting pictures of areas inside the body) can magnify or zoom in on an area. From the patient’s perspective, the procedure for a mammogram with a digital system is the same as for conventional mammography.

Digital mammography may have some advantages over conventional mammography. The images can be stored and retrieved electronically, which makes long-distance consultations with other mammography specialists easier. Because the images can be adjusted by the radiologist, subtle differences between tissues may be noted. The improved accuracy of digital mammography may reduce the number of followup procedures. Despite these benefits, studies have not yet shown that digital mammography is more effective in finding cancer than conventional mammography.

The first digital mammography system received U.S. Food and Drug Administration (FDA) approval in 2000. An example of a digital mammography system is the Senographe® 2000D. Women considering digital mammography should talk with their doctor or contact a local FDA-certified mammography center to find out if this technique is available at that location. Only facilities that have been certified to practice conventional mammography and have FDA approval for digital mammography may offer the digital system. A list of conventional mammography facilities is available by calling the Cancer Information Service at 1–800–4–CANCER (1–800–422–6237), or by visiting the FDA Web site at http://www.fda.gov/cdrh/mammography/certified.html on the Internet.

Computer-Aided Detection

Computer-aided detection (CAD) involves the use of computers to bring suspicious areas on a mammogram to the radiologist’s attention. It is used after the radiologist has done the initial review of the mammogram.

In 1998, the FDA approved a breast imaging device that uses CAD technology. Others are in development. An example of a breast imaging device that uses CAD technology is the ImageChecker®. This device scans the mammogram with a laser beam and converts it into a digital signal that is processed by a computer. The image is then displayed on a video monitor, with suspicious areas highlighted for the radiologist to review. The radiologist can compare the digital image with the conventional mammogram to see if any of the highlighted areas were missed on the initial review and require further evaluation. CAD technology may improve the accuracy of screening mammography. The incorporation of CAD technology to digital mammography is under evaluation.

MRI

In magnetic resonance imaging (MRI), a magnet linked to a computer creates detailed pictures of areas inside the body without the use of radiation. Each MRI produces hundreds of images of the breast from side-to-side, top-to-bottom, and front-to-back. The images are then interpreted by a radiologist.

During an MRI of the breast, the patient lies on her stomach on the scanning table. The breast hangs into a depression or hollow in the table, which contains coils that detect the magnetic signal. The table is moved into a tube-like machine that contains the magnet. After an initial series of images has been taken, the patient may be given a contrast agent intravenously (by injection into a vein). The contrast agent is not radioactive; it is sometimes used to improve the visibility of a tumor. Additional images are then taken. The entire imaging session takes about 1 hour.

Breast MRI is not used for routine breast cancer screening, but clinical trials (research studies with people) are being performed to determine if MRI is valuable for screening certain women, such as young women at high risk for breast cancer. MRI cannot always accurately distinguish between cancer and benign (noncancerous) breast conditions. Like ultrasound, MRI cannot detect microcalcifications.

MRI is used primarily to evaluate breast implants for leaks or ruptures, and to assess abnormal areas that are seen on a mammogram or are felt after breast surgery or radiation therapy. It can be used after breast cancer is diagnosed to determine the extent of the tumor in the breast. MRI is also sometimes useful in imaging dense breast tissue, which is often found in younger women, and in viewing breast abnormalities that can be felt but are not visible with conventional mammography or ultrasound.

PET Scan

The positron emission tomography (PET) scan creates computerized images of chemical changes that take place in tissue. The patient is given an injection of a substance that consists of a combination of a sugar and a small amount of radioactive material. The radioactive sugar can help in locating a tumor, because cancer cells take up or absorb sugar faster than other tissues in the body.

After receiving the radioactive drug, the patient lies still for about 45 minutes while the drug circulates throughout the body. If a tumor is present, the radioactive sugar will accumulate in the tumor. The patient then lies on a table, which gradually moves through the PET scanner 6 to 7 times during a 45-minute period. The PET scanner is used to detect the radiation. A computer translates this information into the images that are interpreted by a radiologist.

PET scans may play a role in determining whether a breast mass is cancerous. However, PET scans are more accurate in detecting larger and more aggressive tumors than they are in locating tumors that are smaller than 8 mm and/or less aggressive. They may also detect cancer when other imaging techniques show normal results. PET scans may be helpful in evaluating and staging recurrent disease (cancer that has come back).

An NCI-sponsored clinical trial is evaluating the usefulness of PET scan results in women who have breast cancer compared with the findings from other imaging and diagnostic techniques. This trial is also studying the effectiveness of PET scans in tracking the response of a tumor to treatment.

Electrical Impedance Scanning

Different types of tissue have different electrical impedance levels (electrical impedance is a measurement of how fast electricity travels through a given material). Some types of tissue have high electrical impedance, while others have low electrical impedance. Breast tissue that is cancerous has a much lower electrical impedance (conducts electricity much better) than normal breast tissue. Electrical impedance scanning devices are used along with conventional mammography to detect breast cancer. The T-Scan 2000, also known as the T-Scan, is an example of such a device. The FDA approved the T-Scan 2000 in 1999.

The electrical impedance scanning device, which does not emit any radiation, consists of a hand-held scanning probe and a computer screen that displays two-dimensional images of the breast. An electrode patch, similar to that used for an electrocardiogram, is placed on the patient’s arm. A very small amount of electric current, about the same amount used by a small penlight battery, is transmitted through the patch and into the body. The current travels through the breast, where it is measured by the scanning probe placed over the breast. An image is generated from the measurements of electrical impedance. Because breast cancer cells conduct electricity better than normal breast cells and tend to have lower electrical impedance, breast tumors may appear as bright white spots on the computer screen.

This device can confirm the location of abnormal areas that were detected by a conventional mammogram. The scanner sends the image directly to a computer, allowing the radiologist to move the probe around the breast to get the best view of the area being examined. The device may reduce the number of biopsies needed to determine whether a mass is cancerous. It may also improve the identification of women who should have a biopsy.

The scanner is not approved as a screening device for breast cancer, and is not used when mammography or other findings clearly indicate the need for a biopsy. This device has not been studied with patients who have implanted electronic devices, such as pacemakers. It is not recommended for use on such patients.

Image-Guided Breast Biopsy Techniques

Imaging techniques play an important role in helping doctors perform breast biopsies, especially of abnormal areas that cannot be felt but can be seen on a conventional mammogram or with ultrasound. One type of needle biopsy, the stereotactic-guided biopsy, involves the precise location of the abnormal area in three dimensions using conventional mammography. (Stereotactic refers to the use of a computer and scanning devices to create three-dimensional images.) A needle is then inserted into the breast and a tissue sample is obtained. Additional samples can be obtained by moving the needle within the abnormal area.

Another type of needle biopsy uses a different system, known as the Mammotome® breast biopsy system. The FDA approved Mammotome in 1996; the hand-held version of the Mammotome received FDA clearance in September 1999. A large needle is inserted into the suspicious area using ultrasound or stereotactic guidance. The Mammotome is then used to gently vacuum tissue from the suspicious area. Additional tissue samples can be obtained by rotating the needle. This procedure can be performed with the patient lying on her stomach on a table. If the hand-held device is used, the patient may lie on her back or in a seated position.

There have been no reports of serious complications resulting from the Mammotome breast biopsy system. Women interested in this procedure should talk with their doctor.

Ductal Lavage

Ductal lavage is an investigational technique for collecting samples of cells from breast ducts for analysis under a microscope. A saline (salt water) solution is introduced into a milk duct through a catheter (a thin, flexible tube) that is inserted into the opening of the duct on the surface of the nipple. Fluid, which contains cells from the duct, is withdrawn through the catheter. The cells are checked under a microscope to identify changes that may indicate cancer or changes that may increase the risk for breast cancer. The usefulness of ductal lavage is still under study.

QUIT CIGARETTE SMOKING

Here are some facts to encourage you to QUIT SMOKING

Key Points Cigarette smoking causes 87 percent of lung cancer deaths and is responsible for most cancers of the larynx, oral cavity and pharynx, esophagus, and bladder (see Question 1). Secondhand smoke is responsible for an estimated 3,000 lung cancer deaths among U.S. nonsmokers each year (see Question 2). Tobacco smoke contains thousands of chemical agents, including over 60 substances that are known to cause cancer (see Question 3). The risk of developing smoking-related cancers, as well as noncancerous diseases, increases with total lifetime exposure to cigarette smoke (see Question 4). Smoking cessation has major and immediate health benefits, including decreasing the risk of lung and other cancers, heart attack, stroke, and chronic lung disease (see Question 5).

Tobacco use, particularly cigarette smoking, is the single most preventable cause of death in the United States. Cigarette smoking alone is directly responsible for approximately 30 percent of all cancer deaths annually in the United States (1). Cigarette smoking also causes chronic lung disease (emphysema and chronic bronchitis), cardiovascular disease, stroke, and cataracts. Smoking during pregnancy can cause stillbirth, low birthweight, Sudden Infant Death Syndrome (SIDS), and other serious pregnancy complications (2). Quitting smoking greatly reduces a person’s risk of developing the diseases mentioned, and can limit adverse health effects on the developing child.

1. What are the effects of cigarette smoking on cancer rates?

Cigarette smoking causes 87 percent of lung cancer deaths (1). Lung cancer is the leading cause of cancer death in both men and women (3). Smoking is also responsible for most cancers of the larynx, oral cavity and pharynx, esophagus, and bladder. In addition, it is a cause of kidney, pancreatic, cervical, and stomach cancers (2, 4), as well as acute myeloid leukemia (2).

2. Are there any health risks for nonsmokers?

The health risks caused by cigarette smoking are not limited to smokers. Exposure to secondhand smoke, or environmental tobacco smoke (ETS), significantly increases the risk of lung cancer and heart disease in nonsmokers, as well as several respiratory illnesses in young children (5). (Secondhand smoke is a combination of the smoke that is released from the end of a burning cigarette and the smoke exhaled from the lungs of smokers.) The U.S. Environmental Protection Agency (EPA), the National Institute of Environmental Health Science’s National Toxicology Program, and the World Health Organization’s International Agency for Research on Cancer (IARC) have all classified secondhand smoke as a known human carcinogen—a category reserved for agents for which there is sufficient scientific evidence that they cause cancer (5, 6, 7). The U.S. EPA has estimated that exposure to secondhand smoke causes about 3,000 lung cancer deaths among nonsmokers and is responsible for up to 300,000 cases of lower respiratory tract infections in children up to 18 months of age in the United States each year (5). For additional information on ETS, see the NCI fact sheet Environmental Tobacco Smoke, which can be found at http://www.cancer.gov/cancertopics/factsheet/Tobacco/ETS on the Internet.

3. What harmful chemicals are found in cigarette smoke?

Cigarette smoke contains about 4,000 chemical agents, including over 60 carcinogens (8). In addition, many of these substances, such as carbon monoxide, tar, arsenic, and lead, are poisonous and toxic to the human body. Nicotine is a drug that is naturally present in the tobacco plant and is primarily responsible for a person’s addiction to tobacco products, including cigarettes. During smoking, nicotine is absorbed quickly into the bloodstream and travels to the brain in a matter of seconds. Nicotine causes addiction to cigarettes and other tobacco products that is similar to the addiction produced by using heroin and cocaine (9).

4. How does exposure to tobacco smoke affect the cigarette smoker?

Smoking harms nearly every major organ of the body (2). The risk of developing smoking-related diseases, such as lung and other cancers, heart disease, stroke, and respiratory illnesses, increases with total lifetime exposure to cigarette smoke (7). This includes the number of cigarettes a person smokes each day, the intensity of smoking (i.e., the size and frequency of puffs), the age at which smoking began, the number of years a person has smoked, and a smoker’s secondhand smoke exposure.

5. How would quitting smoking affect the risk of developing cancer and other diseases?

Smoking cessation has major and immediate health benefits for men and women of all ages. Quitting smoking decreases the risk of lung and other cancers, heart attack, stroke, and chronic lung disease. The earlier a person quits, the greater the health benefit. For example, research has shown that people who quit before age 50 reduce their risk of dying in the next 15 years by half compared with those who continue to smoke (3). Smoking low-yield cigarettes, as compared to cigarettes with higher tar and nicotine, provides no clear benefit to health (2). For additional information on quitting smoking, see the NCI fact sheet Questions and Answers About Smoking Cessation, which can be found at http://www.cancer.gov/cancertopics/factsheet/Tobacco/cessation on the Internet.

6. What additional resources are available?

For additional information about cancer or tobacco use, call 1–800–4–CANCER or visit the NCI’s Web site about tobacco at http://www.cancer.gov/cancerinfo/tobacco on the Internet.

For help with quitting smoking, call NCI’s smoking cessation quitline at 1–877–44U–QUIT or visit NCI’s smoking cessation Web site at http://www.smokefree.gov on the Internet.

Information about the health risks of smoking is also available from Centers for Disease Control and Prevention’s Office on Smoking and Health (OSH) at 1–800–CDC–1311 (1–800–232–1311) or via their Web site at http://www.cdc.gov/tobacco on the Internet.

these questions and facts were aimed at creating a general awareness about the ill effects of smoking . To learn the methodical way to quit smoking please visit QUIT SMOKING

Mesothelioma

Questions and Answers

Mesothelioma is a rare form of cancer in which malignant (cancerous) cells are found in the mesothelium, a protective sac that covers most of the body’s internal organs. Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles.

1. What is the mesothelium?

The mesothelium is a membrane that covers and protects most of the internal organs of the body. It is composed of two layers of cells: One layer immediately surrounds the organ; the other forms a sac around it. The mesothelium produces a lubricating fluid that is released between these layers, allowing moving organs (such as the beating heart and the expanding and contracting lungs) to glide easily against adjacent structures.

The mesothelium has different names, depending on its location in the body. The peritoneum is the mesothelial tissue that covers most of the organs in the abdominal cavity. The pleura is the membrane that surrounds the lungs and lines the wall of the chest cavity. The pericardium covers and protects the heart. The mesothelial tissue surrounding the male internal reproductive organs is called the tunica vaginalis testis. The tunica serosa uteri covers the internal reproductive organs in women.

2. What is mesothelioma?

Mesothelioma (cancer of the mesothelium) is a disease in which cells of the mesothelium become abnormal and divide without control or order. They can invade and damage nearby tissues and organs. Cancer cells can also metastasize (spread) from their original site to other parts of the body. Most cases of mesothelioma begin in the pleura or peritoneum.

3. How common is mesothelioma?

Although reported incidence rates have increased in the past 20 years, mesothelioma is still a relatively rare cancer. About 2,000 new cases of mesothelioma are diagnosed in the United States each year. Mesothelioma occurs more often in men than in women and risk increases with age, but this disease can appear in either men or women at any age.

4. What are the risk factors for mesothelioma?

Working with asbestos is the major risk factor for mesothelioma. A history of asbestos exposure at work is reported in about 70 percent to 80 percent of all cases. However, mesothelioma has been reported in some individuals without any known exposure to asbestos.

Asbestos is the name of a group of minerals that occur naturally as masses of strong, flexible fibers that can be separated into thin threads and woven. Asbestos has been widely used in many industrial products, including cement, brake linings, roof shingles, flooring products, textiles, and insulation. If tiny asbestos particles float in the air, especially during the manufacturing process, they may be inhaled or swallowed, and can cause serious health problems. In addition to mesothelioma, exposure to asbestos increases the risk of lung cancer, asbestosis (a noncancerous, chronic lung ailment), and other cancers, such as those of the larynx and kidney.

Smoking does not appear to increase the risk of mesothelioma. However, the combination of smoking and asbestos exposure significantly increases a person’s risk of developing cancer of the air passageways in the lung.

5. Who is at increased risk for developing mesothelioma?

Asbestos has been mined and used commercially since the late 1800s. Its use greatly increased during World War II. Since the early 1940s, millions of American workers have been exposed to asbestos dust. Initially, the risks associated with asbestos exposure were not known. However, an increased risk of developing mesothelioma was later found among shipyard workers, people who work in asbestos mines and mills, producers of asbestos products, workers in the heating and construction industries, and other tradespeople. Today, the U.S. Occupational Safety and Health Administration (OSHA) sets limits for acceptable levels of asbestos exposure in the workplace. People who work with asbestos wear personal protective equipment to lower their risk of exposure.

The risk of asbestos-related disease increases with heavier exposure to asbestos and longer exposure time. However, some individuals with only brief exposures have developed mesothelioma. On the other hand, not all workers who are heavily exposed develop asbestos-related diseases.

There is some evidence that family members and others living with asbestos workers have an increased risk of developing mesothelioma, and possibly other asbestos-related diseases. This risk may be the result of exposure to asbestos dust brought home on the clothing and hair of asbestos workers. To reduce the chance of exposing family members to asbestos fibers, asbestos workers are usually required to shower and change their clothing before leaving the workplace.

6. What are the symptoms of mesothelioma?

Symptoms of mesothelioma may not appear until 30 to 50 years after exposure to asbestos. Shortness of breath and pain in the chest due to an accumulation of fluid in the pleura are often symptoms of pleural mesothelioma. Symptoms of peritoneal mesothelioma include weight loss and abdominal pain and swelling due to a buildup of fluid in the abdomen. Other symptoms of peritoneal mesothelioma may include bowel obstruction, blood clotting abnormalities, anemia, and fever. If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, trouble swallowing, or swelling of the neck or face.

These symptoms may be caused by mesothelioma or by other, less serious conditions. It is important to see a doctor about any of these symptoms. Only a doctor can make a diagnosis.

7. How is mesothelioma diagnosed?

Diagnosing mesothelioma is often difficult, because the symptoms are similar to those of a number of other conditions. Diagnosis begins with a review of the patient’s medical history, including any history of asbestos exposure. A complete physical examination may be performed, including x-rays of the chest or abdomen and lung function tests. A CT (or CAT) scan or an MRI may also be useful. A CT scan is a series of detailed pictures of areas inside the body created by a computer linked to an x-ray machine. In an MRI, a powerful magnet linked to a computer is used to make detailed pictures of areas inside the body. These pictures are viewed on a monitor and can also be printed.

A biopsy is needed to confirm a diagnosis of mesothelioma. In a biopsy, a surgeon or a medical oncologist (a doctor who specializes in diagnosing and treating cancer) removes a sample of tissue for examination under a microscope by a pathologist. A biopsy may be done in different ways, depending on where the abnormal area is located. If the cancer is in the chest, the doctor may perform a thoracoscopy. In this procedure, the doctor makes a small cut through the chest wall and puts a thin, lighted tube called a thoracoscope into the chest between two ribs. Thoracoscopy allows the doctor to look inside the chest and obtain tissue samples. If the cancer is in the abdomen, the doctor may perform a peritoneoscopy. To obtain tissue for examination, the doctor makes a small opening in the abdomen and inserts a special instrument called a peritoneoscope into the abdominal cavity. If these procedures do not yield enough tissue, more extensive diagnostic surgery may be necessary.

If the diagnosis is mesothelioma, the doctor will want to learn the stage (or extent) of the disease. Staging involves more tests in a careful attempt to find out whether the cancer has spread and, if so, to which parts of the body. Knowing the stage of the disease helps the doctor plan treatment.

Mesothelioma is described as localized if the cancer is found only on the membrane surface where it originated. It is classified as advanced if it has spread beyond the original membrane surface to other parts of the body, such as the lymph nodes, lungs, chest wall, or abdominal organs.

8. How is mesothelioma treated?

Treatment for mesothelioma depends on the location of the cancer, the stage of the disease, and the patient’s age and general health. Standard treatment options include surgery, radiation therapy, and chemotherapy. Sometimes, these treatments are combined.

• Surgery is a common treatment for mesothelioma. The doctor may remove part of the lining of the chest or abdomen and some of the tissue around it. For cancer of the pleura (pleural mesothelioma), a lung may be removed in an operation called a pneumonectomy. Sometimes part of the diaphragm, the muscle below the lungs that helps with breathing, is also removed.
• Radiation therapy, also called radiotherapy, involves the use of high-energy rays to kill cancer cells and shrink tumors. Radiation therapy affects the cancer cells only in the treated area. The radiation may come from a machine (external radiation) or from putting materials that produce radiation through thin plastic tubes into the area where the cancer cells are found (internal radiation therapy).
• Chemotherapy is the use of anticancer drugs to kill cancer cells throughout the body. Most drugs used to treat mesothelioma are given by injection into a vein (intravenous, or IV). Doctors are also studying the effectiveness of putting chemotherapy directly into the chest or abdomen (intracavitary chemotherapy).

To relieve symptoms and control pain, the doctor may use a needle or a thin tube to drain fluid that has built up in the chest or abdomen. The procedure for removing fluid from the chest is called thoracentesis. Removal of fluid from the abdomen is called paracentesis. Drugs may be given through a tube in the chest to prevent more fluid from accumulating. Radiation therapy and surgery may also be helpful in relieving symptoms.

9. Are new treatments for mesothelioma being studied?

Yes. Because mesothelioma is very hard to control, the National Cancer Institute (NCI) is sponsoring clinical trials (research studies with people) that are designed to find new treatments and better ways to use current treatments. Before any new treatment can be recommended for general use, doctors conduct clinical trials to find out whether the treatment is safe for patients and effective against the disease. Participation in clinical trials is an important treatment option for many patients with mesothelioma.

People interested in taking part in a clinical trial should talk with their doctor. Information about clinical trials is available from the Cancer Information Service (CIS) (see below) at 1–800–4–CANCER. Information specialists at the CIS use PDQ®, NCI’s cancer information database, to identify and provide detailed information about specific ongoing clinical trials. Patients also have the option of searching for clinical trials on their own. The clinical trials page on the NCI’s Cancer.gov Web site, located at http://www.cancer.gov/clinical_trials on the Internet, provides general information about clinical trials and links to PDQ.

People considering clinical trials may be interested in the NCI booklet Taking Part in Clinical Trials: What Cancer Patients Need To Know. This booklet describes how research studies are carried out and explains their possible benefits and risks. The booklet is available by calling the CIS, or from the NCI Publications Locator Web site at http://www.cancer.gov/publications on the Internet.