Cancer Agent List Expanded

The government is adding viruses for the first time to its list of known or suspected causes of cancer, including hepatitis B and C and a third virus that causes sexually transmitted diseases. X-rays, lead and compounds in grilled meats also are joining the list.

It has been known that the hepatitis viruses can cause liver cancer and that some forms of the sexually transmitted human papilloma virus can cause cervical cancer.

But they were added to the list Monday after officials decided to go beyond the report’s historical focus on the occupational and environmental causes of cancer, said Dr. Christopher Portier, associate director of the National Toxicology Program, which prepared the latest update.

Dr. Michael Thun, who runs the American Cancer Society’s epidemiological program, said adding the viruses was important. “These are human carcinogens and very important carcinogens,” he said.

The list, which now identifies 246 known or suspected cancer-causing agents, is intended to give people something to think about, he said.

Take X-rays, added to the “known” category. “This is simply to remind them that when they are making a decision about an X-ray to think about it and talk it over with your physician,” Portier said.

But the American College of Radiology faulted the addition of X-rays and gamma rays, saying it was misleading and could prompt patients to avoid getting needed care.

“X-rays and gamma rays are not substances that the general public has access or exposure to and do not belong on a list of substances that pose a risk to people in the course of their normal, daily lives,” Dr. James Borgstede, chairman of the radiology college’s board of chancellors, said in a statement.

New to the suspected category are substances that form when meats are cooked or grilled at high temperatures. Studies suggest an increased cancer risk when foods containing them are eaten.