What is CTC method?
CTC method which has been approved by the US Federal Drug Administration (FDA) for certain types of cancer and is currently applied in a few countries (like Germany, Italy and US) depends on a simple blood test. Cancerous cells and number of cancerous cells, even the type of cancer can be identified with blood samples examined under a special device. Moreover, all these can be determined at a very early phase of cancer.
What are the differences of the CTC method from other methods?
As it is known, parameters such as growth of the tumor to a certain size, spreading of the tumor to the lymph node and to organs remote from its location are used in classic cancer phasing. However, thanks to the CTC method, tumor cells that penetrate into the blood can be detected before the tumor reaches a certain size, i.e. a size that can be detected with current screening methods. This means diagnosis of cancer at a very early stage in some types of cancer. Thus, the CTC method ensures to plan treatment at an early stage and to estimate in advance whether cancer responds to treatment or not. With treatment planning specific to the person, the patient also experiences a more comfortable screening process.
Who are eligible for the CTC method and how is the method applied?
Any patient who has no problem with giving blood is eligible for the method. A tube of blood collected from the patient is examined with a special instrument. The patient can be full or hungry before blood collection. Even the patient does not have to come to take blood. However, for a healthy result, the blood collected within the day should be processed within 30 hours at room temperature.
Certain types of cancer (lung, breast, prostate, colorectal tumors) can be detected at an early stage thanks to the new CTC method. Fortunately, these types of cancer have markers that other cells do not, and using these markers, they can be distinguished from other cells in the blood. At subsequent stages, the organ involved can be found.
What are the stages of the CTC method?
At the first stage, cells constituting normal blood composition in the blood sample taken are distinguished, and through some special algorithms, other cell structures, if any, can be detected. A fluid that eliminates blood cells and intensively contains other cells in circulation is formed and is prepared for use in subsequent processes. At the second stage, it is examined whether there are cancerous cells in that fluid or not based on the characteristics on the surface of cancerous cells. If such characteristics exist and the number of cells is above a certain amount, the diagnosis of cancer can be made definitely. Thus, the new method both detects cancerous cells and their amount, and also identifies the type of cancer. All these stages can be completed in a total of 4 days.
After the diagnosis of cancer, the treatment processes is initiated. In the CTC method, it is examined whether there is any quantitative reduction in the number of cancerous cells in blood in circulation by examining blood count before treatment and shortly after the treatment. This provides important information about the effect of treatment on cancerous cells. Even 1-2 weeks after the first course of treatment (administration of medications) it is possible to see positive outcome in tumor cells in circulation.
If any cancerous cell is not detected in the blood, this should never be construed as “there is no cancer”. It is because cells may not have passed to the blood from the cancerous tissue or cancerous cells may have changed their superficial characteristics and become unidentifiable. For this reason, failure to detect tumor cells does not necessarily mean no cancer. However, if cancerous cells have been detected and are above a certain number, this means presence of cancer unless otherwise proven, and is regarded as an important proof.