First blood test to detect cancer?

Press, 13 January 1987, Page 22

First blood test to detect cancer?

By

GENE EMERY

of Reuters Boston A team of medical researchers have said the first blood test to detect most types of cancer may have been discovered. The researchers reported that, in preliminary experiments, the test detected a wide range of tumours, some less than half an inch in diameter, with 90 per cent accuracy. The test, developed by scientists at Beth Israel Hospital, Boston, apparently can distinguish between malignant and nonmaiignant tumours, and “may be applicable to many — perhaps all — types of cancer,” said the team’s leader, Dr Eric Fossel, a biophysicist “Our procedure is simple, quick and could be quite inexpensive,” he told a news conference. ’ However, Dr Fossel emphasised that further research is needed to determine if the test can spot tumours too sqjall to be diagnosed by other techniques. It will probably be two years, he predicted, before the test is available for widespread use. “It is a preliminary but promising test that needs

considerably more experimental work before it can be adapted into a clinical test for the public,” he said. “But you bet I’m excited.”

The initial experiments, reported in the “New England Journal of Medicine,” were done on the blood of 331 volunteers, 81 of whom actually had malignant cancer.

The researchers said the test, which measures the magnetic properties of chemicals in the blood, did not work for everyone.

Pregnant women and people with benign prostate tumours, for example, got a positive reading on the test even though they were cancer-free.

A team member, Dr Justine Carr, a pathologist, said the researchers were surprised that pregnancy produced a positive result until they realised that a pregnant woman, like a cancer victim, also has a rapidly growing mass of cells in her body — a foetus.

“Perhaps the rapid proliferation is signalling back to the host,” she said.

Prostate patients, she said, may get a positive reading in cases where

the tumour is about to become malignant. However, the researchers were unable to fool the test by using blood samples from volunteers with many types of benign growths and serious medical problems.

The test is not able to pinpoint the location of the cancer cells, only of their existence, the researchers said.. “Our test does not direct you to any place in the body because cancer anywhere in the body" gives the same response,” Dr Fossel! said.

, However if physicians know some type of cancer is present, he said, they are then more likely to find its location by running disease-specific tests.

Doctors have been seeking a simple, accurate blood test for cancer for nearly two decades.

The new test uses a technique called nuclear magnetic resonance (N.M.R.), a method used by chemists for years as a way to study the structure of chemicals.

The technique relies on the fact that certain types of atoms give off radio waves when they are placed within a strong magnetic field and radio

waves of a specific frequency are aimed at them.

The signals returned from the target can offer clues to its chemical composition.

The machine used to conduct the procedure, already on the market, costs about SUSSOO,OOO ($970,000.)

The technique has also been used in recent years by magnetic resonance imagers that take crosssectional pictures of the body in the same way a CAT.-scanner works.

Researchers have been trying for years to determine a way that N.M.R. could help to identity cancerous cells. The breakthrough came when the Beth Israel researchers used a technique that removes the signal emitted by the water contained in blood plasma.

They said It was the tell-tale shape of the remaining signal that allowed . them to detect malignant tumours.

The researchers said it is not clear why the blood of cancer victims responds differently to the N.M.R. machine.