X-rays Added to Cancer List

Some Viruses Also Among Carcinogens on Federal Registry 

JANE KAY / SF Chronicle 1feb2005

11th Report on Carcinogens at website of National Institute of Health

The federal government for the first time has placed X-rays and some viruses on its list of cancer-causing agents along with chemicals formed by frying and grilling meat.

Also on the list of 17 new carcinogens, released Monday, were lead and lead compounds, toilet bowl deodorants and substances in textile dyes, paints and inks.

Placing them in the influential "Report on Carcinogens" is significant because government agencies use the report as a definitive guide when considering new environmental, consumer and occupational health regulations.

The list, updated every two years by the U.S. Department of Health and Human Services, now includes 58 substances known to cause cancer and 188 classed as "reasonably anticipated" to cause cancer.

X-rays and gamma radiation — used in medicine, the nuclear power industry and by the military — were listed because they can cause leukemia and thyroid, breast and lung cancers, federal scientists said. X-rays to women in their reproductive years increase the risk of breast cancer, while childhood exposure is linked to an increased risk for leukemia and thyroid cancer, the report said.

Hepatitis B and C viruses made the list because they can cause liver cancer. Some of the sexually transmitted human papillomaviruses, or HPVs, were added for their role in causing cervical cancer in women. About 20 million people are infected with genital HPVs, and 5.5 million are newly infected each year.

Scientists included some viruses in the report because they are causing widespread public health problems. About 1 million people are infected with Hepatitis B, half contracting it through sexual contact and 15 percent through intravenous drug use. The virus can be spread by food handlers. More than 3 million are infected with Hepatitis C. Sixty percent of the acute infections in adults are attributed to intravenous drug use.

The American College of Radiology, which accredits radiologists, took umbrage at the addition of radiation to the list.

James Borgstede, chairman of the board of chancellors, issued a statement saying that X-rays and gamma rays "do not belong on a list of substances that pose a risk to people in the course of their normal, daily lives. This report could lead patients to mistakenly believe that they are being placed at undue risk by undergoing a radiological procedure and cause many who may desperately need care to avoid seeking appropriate medical attention."

In San Francisco, Dr. Daniel Glaubiger, chairman of the Department of Radiation Oncology at California Pacific, said radiologists follow common guidelines to reduce the potential for harm.

"No one should have unnecessary X-rays, particularly children and certainly women who are pregnant," he said. "We know from other data that multiple low-dose X-ray exposures can result in increased incidence of subsequent malignancy."

People shouldn't refuse necessary X-rays, such as those following a head trauma or to determine the extent of pneumonia, Glaubiger cautioned. "Mammograms remain the best screening procedure for women with breast cancer, " he said.

On the other hand, he cautioned that "full body scans involve a fairly sizable exposure and haven't proven beneficial."

About 55 percent of the global radiation exposure comes from medical diagnostic tests, 43 percent from naturally occurring radon and 2 percent from industry, scientific research, military weapons testing, nuclear accidents and nuclear power generation, the report said.

Studies of out-of-date radiation practices have shown an increase in cancer. The ongoing California Teachers Study has shown a higher-than-average risk of breast cancer among women required to have yearly chest X-rays to rule out tuberculosis. Canadian women treated for TB with many fluoroscopies in the 1930s and 1940s have a higher risk of breast cancer than do women who were monitored for scoliosis with X-rays in the 1950s and 1960s.

Dr. Chris Portier, associate director of the National Toxicology Program, which prepared the report, said he hopes the information will help physicians update their points of view and "re-examine what they're doing."

"We think X-rays have been of great medical benefit. But it's certainly something people should be talking to their doctors about if they're planning a large number of X-rays," said Portier.

Likewise, he said he hopes people will use it as another tool to gauge their everyday habits.

"If people eat a lot of high-temperature cooked meat and eggs, and they get brown or black on the outside, they should know that it's potentially raising their cancer risk from heterocyclic amine compounds," he said.

Portier added that the public should also know there's a vaccine to prevent Hepatitis B, and that physicians can test for the sexually transmitted human papilloma virus that many women have without realizing it.

Cancer is one of the most feared diseases in the United States, and researchers are just beginning to identify some of the harmful chemicals that appear to promote it.

"Among U.S. residents, 1 in 2 men and 1 in 3 women will develop cancer at some point in their lifetimes," said Kenneth Olden, director of the National Toxicology Program and the National Institute of Environmental Health Sciences Research, which prepared the report.

"Research shows that environmental factors trigger diseases like cancer, " Olden said. The report emphasizes that genetics and other factors play a role in terms of an individual's risk.

Scientists compile the carcinogen list — this is the 11th — based on evaluation of thousands of studies and discussion among panels of experts.

Under California's Proposition 65, the chemicals on this federal list are included among those that require warnings if they exceed safety guidelines in products, drinking water or in the environment.

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ADDED TO THE LIST OF CANCER-CAUSING AGENTS 

The government added 17 items - including viruses for the first time- to its growing list of carcinogens that is published every two years.

— Known Carcinogens (6)

Hepatitis B virus

Hepatitis C virus

Some human papillomaviruses

X-rays

Gamma rays, which are used in medicine, the nuclear power industry, the military, scientific research and various consumer products.

Neutrons, used in medicine and research..

— Reasonably Anticipated Carcinogens (11)

1-Amino-2,4-dibromoanthraquinone, a vat dye used in the textile industry.

Cobalt sulfate, used in electroplating and electrochemical industries; as a coloring agent for ceramics; a drying agent in inks, paints, varnishes and linoleum; and in animal feed.

Diazoaminobenzene, used to make dyes and promote the adhesion of natural rubber to steel.

MeIQ, MeIQx and PhIP, heterocyclic amine compounds that are formed when meats and eggs are cooked or grilled at high temperatures. They also are found in cigarette smoke.

Lead and lead compounds. Lead is used to make lead-acid storage batteries, ammunition and cable covering. Lead compounds are used in paint, glass and ceramics; as a fuel additive; and in some cosmetics.

Naphthalene, used in industrial chemicals, moth repellants and toilet bowl deodorants.

Nitrobenzene, used mainly in the production of aniline, a poisonous liquid used to make dyes, resins, rubber additives and agricultural products.

Nitromethane, used in specialized fuels and explosives, among other uses.

4,4-Thiodianiline, used in the preparation of several dyes.

About the National Toxicology Program

Three agencies form the core of the NTP (see Figure below): 

• National Institute of Environmental Health Sciences of the National Institutes of Health (NIEHS/NIH) 
• National Institute for Occupational Safety and Health of the Centers for Disease Control and Prevention (NIOSH/CDC) 
• National Center for Toxicological Research of the Food and Drug Administration (NCTR/FDA) 

The NTP is located administratively at the NIEHS/NIH and the Director of the NIEHS/NIH, Dr. Kenneth Olden, serves as the NTP Director. Dr. Christopher Portier, Associate Director of the NTP, assists the Director in the daily management of the NTP. 

The NTP relies upon three external groups for advice on its activities:

• The NTP Executive Committee 
• NTP Board of Scientific Counselors 
• Scientific Advisory Committee on Alternative Toxicological Methods 

The NTP also uses special emphasis panels for independent scientific peer review and advice on targeted issues. 

source: http://ntp.niehs.nih.gov/ntpweb/index.cfm?objectid=720163E9-BDB7-CEBA-FB0157221EB4375F 1feb2005

More than 80,000 chemicals are registered for use in the United States. Each year, an estimated 2,000 new ones are introduced for use in such everyday items as foods, personal care products, prescription drugs, household cleaners, and lawn care products. We do not know the effects of many of these chemicals on our health, yet we may be exposed to them while manufacturing, distributing, using, and disposing of them or when they become pollutants in our air, water, or soil. Relatively few chemicals are thought to pose a significant risk to human health. However, safeguarding public health depends on identifying both what the effects of these chemicals are and at what levels of exposure they may become hazardous to humans — that is, understanding their toxicology.

The NTP is an interagency program whose mission is to evaluate agents of public health concern by developing and applying tools of modern toxicology and molecular biology. The program maintains an objective, science-based approach in dealing with critical issues in toxicology and is committed to using the best science available to prioritize, design, conduct, and interpret its studies. To that end, the NTP is continually evolving to remain at the cutting edge of scientific research and to develop and apply new technologies.

More . . .

source: http://ntp.niehs.nih.gov/index.cfm?objectid=7201637B-BDB7-CEBA-F57E39896A08F1BB 1feb2005