Gene testing for cancer picks up

In a usual cancer diagnosis, a doctor cuts out a piece of the tumour from different parts of the body and tests it. The lab may take days or even weeks to see if the tumour is cancerous or not, a wait that is agonising.

However, a few Kenyan patients are opting for a faster, more accurate technology that involves a blood test.

The technology, known as liquid biopsy, which involves testing of genes, was launched in Kenya a year ago.

“This is a game-changer in cancer diagnosis. The blood test can detect many cancers at a go, some at stage-zero when there are no symptoms. It also shows whether the cancer is spreading or reducing and which chemotherapy drugs work best because cancer is not one disease,” said Robbin Noreh of Massive Genomics Kenya, one of the few clinics doing such genetic tests in Africa.

So far, the clinic says, it has seen about 150 patients. Some are referred by oncologists who want to know if a patient has a gene mutation and what drugs would work best in treating the cancer.

Some patients walk in with no symptoms, wanting to know if they are at risk of getting cancer, especially in cases where their family members have been diagnosed with the disease. Others come to check residual disease after surgery, radiotherapy and chemotherapy or track treatment progress.

“Some want to know if they are likely to get cancer in two years or 20. The screening tests just make them aware that they are at risk of getting the disease because they inherited a bad gene. In cases where a woman has a mutated BRCA gene, that increases their chance of developing breast and ovarian cancer, one can opt to remove ovaries and breasts,” said Dr Moses Obimbo, an obstetrician and gynaecologist.

900 TYPES

With just a vial of blood, the machine is able to test 900 types of cancer, by checking mutations in 52 genes.

What is interesting is the ability to test for a mutation in a gene called TP53.

Patients with a TP53 gene mutation are advised to avoid exposure to radiation therapy because it may fuel the cancer to spread.

“Without access to new technologies many patients are dying, not because of cancer, but due to wrong treatment,” says Mr Noreh.

The blood test costs Sh100,000, a price that is prohibitive to many cancer patients but he says “it may be costly but for cancer treatment, it is a race against time.

Someone with cancer does not have time to waste on the wrong drugs.

“This test helps patients to be in control of their treatment instead of going on blindly. And instead of a patient having to go through misdiagnosis or random tests, this test is precise,” he says.

Globally, doctors are shifting to precision medicine that aims at “matching the proper medical treatment to the right patient.”

In Kenya, patients are already benefiting from such targeted therapies in treating cancers such as chronic myeloid leukaemia, HER 2-positive breast cancer, and gastrointestinal stromal tumour among others.

For a few years now, patients have been testing for one gene mutation or proteins that promote the growth of cancer cells. However, genomic experts say testing all the genes, instead of one, gives a better picture in cancer diagnosis.

GENOME DATA

“For most cancer patients, what they want from their oncology clinic is this; ‘Take a sample from my tumour (or even better from my blood), test it for the best possible drug and get back to me with that drug as fast as possible”!, said a team of experts from Uppsala University’s Department of Immunology, Genetics and Pathology, during a cancer conference in Sweden last year.

Laban Mwiti, a genome data scientist at Massive Genomics says the 52 genes-testing also helps to understand if Kenyans have unique variants of cancer that may require different treatments compared to those in Asia or Europe.

“We don’t have data showing the most common mutations among cancer Kenyan patients and some doctors may be doing guesswork in treating them,” he said.