Cancer is painful. It is a leading cause of death in the world. The diagnosis procedure is long and invasive. There is a demand for better diagnostic measures for cancer.
To make an accurate diagnosis, doctors have to wait until patients start exhibiting symptoms of cancer. Even then, cases of misdiagnosis are common. It is almost impossible to treat cancer successfully if you wait for symptoms to develop.
Nonetheless, early detection of some types of cancer is possible. Cervical cancer and breast cancer are some of the few cancers that can be detected early. A mammogram is used to detect breast cancer, while a pap smear is carried out to detect the cervix’s cancer.
Scientists have worked on and developed a simple blood test that can identify over 50 types of cancer. This is a huge milestone in the world of medicine. This test’s main advantage is that it can detect cancer way before the development of clinical symptoms. All that is required is a single draw of blood.
How Is Cancer Diagnosed?
A cancer diagnosis can be challenging. Some diseases and infections exhibit the symptoms of cancer. Whatever the case, correct diagnosis is critical. Misdiagnosis can be dangerous and even fatal.
The following are examples of cancer diagnosis procedures:
- Lab tests
- Diagnostic imaging
- Genetic tests
- Endoscopic examinations
- Tumor biopsies
In some cases, the testing can be done severally, especially when the person’s condition has changed or when cancer spreads. Irregular test results may also warrant a repeat test.
How Does the Test Work?
For a long time, oncologists made treatment decisions based on two major aspects. First, they needed to identify where cancer cells initially started to grow. Secondly, oncologists needed to establish whether cancer has spread to other organs or not.
Treatment was also dependent on whether the patient had other underlying health conditions. Sample tissues were tested for cancer cells.
Indeed, blood tests have not been the ideal way to detect cancer. Oddly, this test also failed to detect cancers in patients with blood cancer. Improvement in technology has since changed the narrative. Blood testing can be used to detect cancer.
Testing for cancer cells using blood is called a liquid biopsy. This entails examining the blood for cancer-related materials.
Cancer is a disease that affects the genome. This means that it has specific genomic alterations. On top of this, the DNA in the cancer cells carries cancer-specific signals.
This new blood test identifies cancer in the body by scanning the DNA in the blood. This scan also identifies genetic changes such as mutations. The whole process is known as genomic profiling.
Tumor cells release a type of DNA into the blood. Once in the blood, the tumor cell is known as cell-free DNA (cfDNA). Initially, it was challenging to identify and single out tumor-specific DNA. This is because DNA is released into the blood by a lot of other cells as well.
The new blood test has made it possible for lab personnel to detect DNA specifically from cancer cells. They use a special chemical called a methyl group.
What Blood Tests Have Been Approved?
So far, there are two blood tests approved by the Food and Drug Administrations (FDA).
These tests are:
- Guardant360 CDx
- FoundationOne Liquid CDx
Note that different companies made these tests.
The following is a list of the most commonly used cancer blood tests:
1. Complete Blood Count (CBC)
This blood test is the most common. It measures the amount and state of the various blood cells in a given sample of blood. Blood cells include white blood cells, platelets and red blood cells.
This test is recommended for detecting blood cancers such as lymphoma and leukemia. To determine whether cancer has spread to the bone marrow, doctors will need to carry out a complete blood count.
2. Prostate-Specific Antigen (PSA) Testing
This test is used to detect prostate cancer in its early stages. The test measures protein levels produced by the prostate gland cells in the blood. The protein is referred to as a prostate-specific antigen and is found in the blood.
A high concentration of this antigen in your blood may point to the development of prostate cancer. Note that some benign prostate conditions can also elevate the amount of PSA in the blood.
3. AFP (Alpha-Fetoprotein) Testing
Healthy pregnant women have Alpha-Fetoprotein in their blood. It is made by fetal development. However, it is not present in adult males and women who are not pregnant. Traces of this protein in the blood of non-pregnant individuals is worrying. It may indicate the onset of cancers such as testicular, liver and ovarian cancers.
4. Cancer Antigen 19-9 (CA 19-9) Testing
This blood test detects antigens in the blood that show pancreatic cancer. Additionally, the test can be used to keep track of the treatment of pancreatic cancer.
5. Blood Protein Testing
This test is regularly carried out on patients with blood cancers. . The test looks for abnormal immune system proteins called immunoglobulins in the bloodstream. This kind of test is used in the early detection of Multiple myeloma, which is an aggressive type of blood cancer.
Accuracy of the Test
The new blood tests are relatively accurate.
Several trials have been carried out on this test, and the results have been impressive.
The test posted a 93% accuracy rate. Moreover, it could correctly predict where cancer first developed in the body.
Be that as it may, as with every test, there is always a false positive rate. Luckily, this new test posted a low, almost negligible false positive rate of 0.7%. This means that less than 1% of the people tested would have been misdiagnosed.
It is clear that this new test is safe to use and has an almost perfect success rate.
Suitability of the Test for Hard to Detect Cancers
Some cancers are difficult to detect as the symptoms associated do not develop for a long time. Such cancers are usually not diagnosed until the last stage. In most cases, last-stage cancer is fatal.
It is comforting to note that this new test can accurately detect 67% of the hard to detect cancers.