Summary -The Limitations Of Screening

To conclude, routine screening with the exception of cervical cancer, has been proved to be of benefit in certain well-defined high-risk groups, such as retinal cancer in children who have inherited the trait for retinoblastoma, colon cancer in young people with the trait of polyposis coli, and skin cancers in persons afflicted with xeroderma pigmentosum. The screening service should include a careful follow-up of these genetically handicapped persons.

It would be impracticable to carry out routine screening of people at higher cancer risk for personal reasons, such as smoking, excess consumption of milk-fat or obesity.

What should be contemplated, in view of the increasing mortality from bowel cancer, is the introduction of routine stool examination which might identify persons at particularly high risk to develop bowel cancer.

A simple home test kit to detect hidden blood in the stool, even before bowel symptoms appear, is now on sale in the USA, and about to be released in the UK. The result of the test, in the form of a change in colour, becomes obvious minutes after spraying the specially prepared paper tissue, to which a sample of the stool has been applied, with the provided detector solution.

This home test has proved as reliable as the routinely used hospital laboratory test for occult blood in the stool.

Since successful surgery for bowel cancer entirely depends on early detection, this simple home test should be mandatory for the overweight meat-eaters and others in the high risk group for bowel cancer.

Whereas a blood test for cancer remains impossible, a number of factors which may contribute to a greater likelihood of contracting cancer can already be estimated in a blood-sample. These include constituents of tobacco, dietary factors, medicines, genetic factors and even DNA damage.

Some information on cancer may however already be gleaned from an ordinary blood test. In all, three substances which may help either to monitor response to treatment in established cases or assist in the detection of a fresh recurrence are readily detectable. They are: chorionic gonadotrophin in the rare cancer of the placenta, called choriocarcinoma; the carcino-embryonic antigen which is produced by some cancers of the colon and the alphafetoprotein, which is found in people with advanced liver cancer. The existence of these substances in the blood has been of great help in the handling of these cases and also in the control of their subsequent disease-free survival.