Materia Medica Malaysiana

Indiscriminate testing raises doctors’ concern

Tumour marker tests are being marketed as an early detector of cancer, but doctors say they are unreliable and sometimes inaccurate.

Incorporated into many health or "wellness" packages, these tests are available at some clinics and clinical laboratories, especially in the Klang Valley. They are even marketed directly to staff at companies. The cost ranges from RM20 to RM65.

Doctors said tumour marker tests can either cause unnecessary concern or give a false sense of security. "These tests are a waste of money," said Dr S.K. Dharmalingam, president of the National Cancer Society.

"The authorities should regulate this indiscriminate testing," said Dr Leslie Lai, who last year helped the Academy of Medicine of Malaysia, an association of specialists, produce guidelines on the use of these tests.

Tumour markers are substances produced by cancer cells, and high levels can be found in the blood and urine of patients with cancer.

However, normal cells also produce these markers, sometimes in large amounts in people who do not have cancer.

Almost everyone has a little of these substances in their blood, said Dr Dharmalingam. "This is why sometimes tumour marker tests are not reliable," he said.

Furthermore, low levels do not mean there is no cancer.

"Sometimes, tumour marker levels rise only when cancer is already advanced." "The marker levels are rarely elevated in patients with early malignancy," said Datuk Dr Abdul Hamid Abdul Kadir who heads the Malaysian Medical Council's ethics committee. Tumour markers are best used to monitor how well a cancer patient is responding to treatment. If marker levels fall after treatment, then the doctor knows he is on the right track, for example. "In the United States and the United Kingdom, the use of these tests is tightly regulated," said Dr Lai.

The Department of Health has approved the guidelines produced by the committee Dr Lai headed and distributed to its doctors and hospitals, he said.

The guidelines do not apply to private doctors, however, except as a recommended standard of practice.