Cancer Diagnosis: Blood Test Instead of Biopsy

A new method of diagnosing cancer may replace biopsy.

The standard method of cancer diagnosis involves performing a biopsy of the tumour tissue followed by examination. Biopsy accurately determines whether pathological processes are occurring in the body, but this method is traumatic for the patient. Scientists from Johns Hopkins University have developed an alternative method of investigation – liquid biopsy. The technique called CancerSEEK allows for the diagnosis of eight types of oncological pathologies.

The method involves analyzing the composition of the patient's blood. In the laboratory, tests are conducted for 8 biological markers of proteins and mutations in sixteen genes. The analysis helps determine the presence or absence of cancer in the liver, pancreas, stomach, breast, lungs, intestines, ovaries, and esophagus. Professor Nicholas Papadopoulos, one of the developers of the new method, estimates that the cost of the test for patients will be around five hundred dollars.

Testing with the CancerSEEK method showed 70% accuracy in detecting oncological pathologies without signs of metastasis. The examination was conducted on 1005 patients. The highest effectiveness of liquid biopsy was shown in diagnosing ovarian cancer (98%), while for breast cancer, the accuracy of the test was only 33%. This method helped accurately locate the tumour in 63% of cases.

Problems with the New Method

However, the specific protein that is present during oncological processes can also be found in patients without cancer if they have certain infectious diseases. Thus, the new method gives false-positive results in some cases: in seven out of 812 patients from the control group, who had no oncological pathologies, testing identified the presence of the protein. This makes the study less reliable, but scientists believe that CancerSEEK can still be used for cancer screening. Professor Papadopoulos believes that, despite the method's imperfections, it can still be useful. Currently, the effectiveness of liquid biopsy is being tested: for five years, scientists will observe ten thousand healthy individuals who have undergone testing. Time will tell how suitable CancerSEEK is for widespread use.

After all, another group of scientists from the same university stated in December 2017 that the method was erroneous: two different liquid biopsy tests yielded completely different results, even though they were conducted on the same person. Co-author of this study, Dr. Gonzalo Torga, warns his colleagues that CancerSEEK is unlikely to be considered a reliable cancer diagnostic tool at this time.