Personalized lung cancer treatment
Lung cancer can origin from different types of lung cells and even within the same cell type, caused by various molecular anomalies. In the personalized treatment of a patient, taking into account his individual circumstances, the first step is to identify the cells of the cancer origin. In 10-15% of cases, lung cancer belongs to the subtype of “small cells”. The majority of people, however, suffer from non-small cell lung cancer (NSCLC). This type of lung cancer is classified as squamous cell carcinoma or adenocarcinoma.
In some of these cancer cell subtypes are identified specific molecular targets. It is very important to understand which mutations are the main factor causing uncontrolled tumor growth in a certain patient. If the identified genetic abnormality is the target of a particular medicine, then one can hope for a useful therapeutic effect. Patients should be aware of the difference between lung cancers. An accurate diagnosis can be made by examining tissue taken from a tumor using lung biopsy.
In the treatment of all cancers, the risk of excessive treatment that causes side effects, not benefiting the patient, should be balanced with the risk of underestimation of the disease, leading to ineffective treatment, a decrease in the quality of life and the chance of survival. Over the years, the benefits of chemotherapy for advanced lung cancer have been relatively small. And the toxicity associated with treatment was significant.
During last years the increased ability to understand the molecular mechanisms responsible for the development and progression of NSCLC in specific patient groups has caused need in targeted drug therapy that is more effective and better tolerated by patients. For recommendation of a personalized treatment, our doctors examine the lung cancer tissue for two molecular anomalies:
1. Epidermal growth factor receptor mutations (EGFR);
2. Rearrangement of the gene for anaplastic lymphoma kinase (ALK).
These anomalies confirmed as biomarkers, which predict a good response to specific classes of drugs.
In about 10% of patients with NSCLC, epidermal growth factor receptors are abnormally sensitive, and cell division goes out of control. Cancer with this pathology responds well to a class of oral medications called EGFR tyrosine kinase inhibitors. They block the transmission of growth signals from the activated receptor to the nucleus of the cell. Patients with lung cancer who do not have sensitizing EGFR mutations will react to these agents to a minimal extent.
About 5% of patients with NSCLC have tumors that exhibit anomalies in the ALK gene, which results in an overactive form of the enzyme that stimulates growth. Cancer, which is ALK-positive, responds well to treatment with tyrosine kinase inhibitor that blocks the transmission of growth signals to the cell nucleus.
Asian origin are more likely to have the EGFR mutations. Cancerous lung tumors in women and non-smokers have more chance of developing cancer that promotes ALK mutation. In both cases, the diagnosis of these anomalies requires sophisticated technology and should only be carried out in specialized laboratories in Israel with rigorous procedures to ensure quality control.
In most patients with NSCLC whose tumors do not express EGFR or ALK anomalies, the search will continue using biomarkers that characterize their specific disease and drugs that can be used to treat them.
But care for lung cancer patients can be personalized in many other ways, even when abnormalities were not identified that lead to specific drugs. In this case very important is accurate assessment of the size and location of the primary tumor and the extent of the disease, which may be performed by complex imaging techniques, such as positron emission tomography (PET) and magnetic resonance imaging (MRI). They play an important role in the accurate detection of secondary malignant tumors (metastases) as well.
Tumors of small lung sizes can be treated surgically, often with additional radiation therapy. A disease that has spread locally or to other parts of the body may require systemic treatment. Typically, this is based on chemotherapy drugs containing platinum.
Chemotherapy can be combined with a biological agent, that targets the vascular endothelial growth factor (VEGF). This factor promotes the growth of blood vessels, including those that supply blood to the tumor. Preventing this can lead to a reduction in the tumor.
Because lung cancer is so closely associated with smoking, which has many negative health effects, these patients are often associated with respiratory, cardiac and vascular diseases. Perhaps they are already limited in their activities. These factors may mean that cytotoxic chemotherapy with combination of drugs is not appropriate. An alternative to the use of a single cytotoxic agent is possible. When choosing cancer treatment in personalized medicine, such problems are taken into account by our Israeli oncologists and with the patient’s preferences.
Although 80-90% of cases of lung cancer are caused by smoking, some of them occur in people who have never smoked and are more likely to be found in women than men.
Although targeted biological agents and chemotherapy can stop the growth of many lung cancers within a few weeks or months, or even reduce their size, most tumors eventually resume growth. In this case, effective second-line procedures are needed.
Some patients, at present, are successfully treated by a new class of targeted antibodies, called checkpoint inhibitors. A characteristic feature of many types of cancer is that they find ways to resist the immune response of body. A new class of inhibitors of control points has been described as the removal of brakes from the immune system, which gives him more opportunities to fight cancer.
The first such agent for lung cancer was nivolumab, followed by pembolizumab (Keytruda).
Thus, testing this biomarker and many other procedures mentioned above, is another example of the importance of personalized medicine, which determines the most appropriate treatment, taking into account the specific molecular characteristics of the cancer that affect the certain patient.
Personalized treatment is widely used by our Israeli oncologists in the treatment of lung tumors and proves its effectiveness.