Top Health: How does the test spot cancer cells in the blood?
Prof. Patrizia Paterlini-Bréchot. It is based on the difference in size between blood cells and the larger ones from tumors. The blood collected is diluted and then poured into a cartridge that contains a filter. This cartridge is inserted into a machine that performs filtration: the blood cells, smaller, pass through the pores of the filter and, if there are tumor cells in the blood, these are retained. They are then observed under a microscope by a cytopathologist to verify that they are indeed cancer cells.
How long has it been available?
Prof PP-B. It has been on the market since the end of February (€ 486, not reimbursed). Initially, it was thought to reserve it for people who have a tumor, to find out if cancer cells have passed into the blood, thus risking metastasis in other organs. But this test also allowed doctors from Nice to identify tumor cells in smoking patients, therefore at risk of lung cancer, between one and four years before imaging reveals a cancerous nodule. The test therefore allows very early detection and rapid intervention.
Can we ask for this test if we are not sick?
Prof PP-B. Yes, but you should know that it does not, for the moment, determine which organ the tumor cells come from. For this reason, the person who wishes to do it can only do so on medical prescription, after having signed an informed consent form explaining these limits. The doctor will receive the result. If this is positive, he will order medical imaging tests. If they do not reveal anything, it will be necessary to plan for monitoring. The goal is to detect a tumor in the early stages.
Isn’t there a risk of overdiagnosis or overtreatment?
Prof PP-B. Some localized cancers do not affect the life expectancy of patients. A study showed, in men over 60 who died from causes other than cancer, that half of them had a Prostate cancer localized. If it had been detected, they might have undergone unnecessary surgery that could have negatively impacted their quality of life. However, according to current knowledge, tumor cells are only detected in the blood when the cancer is invasive, in other words potentially dangerous.
More info on www.isetbyrarecells.com.
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