by Dr Dorothy Cooke-Johnson
Until recently, the main early detection cancer tests offered to Bajans have involved pap tests, digital rectal examination, tumour biopsy and PSA’s (Prostate Specific Antigen tests).
Researchers worldwide are searching to develop newer more accurate and less invasive tests for early detection of cancer.
Now, instead of taking a sample biopsy of solid tumour tissue from a suspect lump, a blood test has been developed which can detect the presence of eight common cancers.
It is called CancerSEEK.
It is based on the fact that our blood carries numerous chemicals around the body. Some are to supply and nourish the tissues, such as food, oxygen and hormones.
Waste products such a carbon dioxide are urea-like compounds are taken to organs for removal. Many of the blood’s components can be investigated to advise us of the health status of the body.
CancerSEEK is a minimally invasive procedure, which, in the future, can be done prophylactically on a healthy person to determine whether signs of very early cancer are present.
A positive blood test result has been shown to reliably indicate early stage and curable cancers which are not yet evidenced by any symptoms.
A negative test result can reduce anxiety and prevent the need for further invasive tests for those who do not require them.
Another benefit of CancerSEEK is that several cancers can be screened for at one time, and the blood sample can also be used in routine blood tests and cholesterol checks. Hopefully, in a few years, CancerSEEK will be available at your doctor’s office, or at the Barbados Cancer Society.
The science of the tests is as follows. Cancer is caused by a deformity of the DNA, (deoxyribonucleic acid) found in the nucleus of our cells.
DNA carries our hereditary instructions in special, discreet sequences called “Genes”.
Each gene’s sequence carries the code to make a protein, and the proteins such as enzymes and hormones control our bodies according to set requirements.
As with all the body’s components, the DNA structure is kept accurate by nuclear mechanisms.
If any part of the DNA is mis-aligned or damaged, it is corrected, and the remnants removed to the blood stream
for disposal.
This is where CancerSEEK comes in. Tiny sections of discarded erroneous DNA, which have been selected for disposal, can be detected by CancerSEEK.
It is highly sensitive and can accurately detect mutated fragments of DNA amongst thousands of normal fragments of DNA being carried in the blood plasma.
Researchers who examined the blood content found mutated fragments of DNA typical of cancer of the pancreas, ovary, liver, stomach and oesophagus.
Although the CancerSEEK test is not available yet, the Prostate blood test being offered for a limited time at the Barbados Cancer Society through the research of Prof. R. David Rosin with the Barbados Cancer Society, and Wren Laboratories in the USA uses a similar principle of testing for tiny errant, fragments of mutated DNA in the blood plasma, typical of prostate cancer cells.
Over 500 Bajan men aged 40-plus have participated in this project, held recently at the Society. At present, Prof Rosin is also seeking to contact 50 younger Bajan men between age 25 – 40 as controls for the study. Please call 436 8888 and volunteer to be part of the study.
Dr. Dorothy Cooke-Johnson OBE JP is president of the Barbados Cancer Society.
