Chemotherapy and Beyond – Targeted Drugs

Chemotherapy and Beyond – Targeted Drugs

Chemotherapy (sometimes called "chemo") is a type of cancer treatment in which drugs are used to kill cancer cells. Rapid growth and reproduction is characteristic of cancer cells. Chemotherapy stops or slows the growth and reproduction of cancer cells. However, it can also cause chemotherapy side effects (such as diarrhea or hair loss) by damaging fast-growing normal cells.

Targeted therapies have emerged as a result of the recognition of the cancer cell and intracellular growth signaling pathways at the molecular level, and the achievement of inhibition of the signals stimulating these growth pathways from the inside and outside of the cell with various drugs. The most remarkable achievements in this field have been achieved in lung adenocarcinoma. We call the treatments developed for all these steps as "targeted therapies or smart cancer drugs".

In the process of cancer formation (carcinogenesis), the main reason for the signal transmission pathways that increase growth out of control is genetic mutations.

The identification of these mutations is extremely important in determining which treatment will be beneficial for which patient.

As we understand the molecular pathways and the genetic alterations (e.g mutations) in these pathways, the number of targeted drugs specific for these mutations increases. These developed drugs have led to a prolongation of life expectancy and an increase in the quality of life. The limited life expectancy achieved with chemotherapy in this stage cancer is significantly prolonged in patients who are suitable for targeted therapies.

These special molecular changes in the cancer cell are revealed as a result of analysis made from the DNA of the tumor. There are two ways to determine the suitability of mutations with targeted drugs in patients diagnosed with cancer. The first of these is the molecular tests performed on the tumor tissue taken from the patient by biopsy. The second is liquid biopsies that are becoming more reliable and have been increasingly preferred in recent years. In other words, these tests are performed by taking a blood sample without the need for biopsy from the patient. In these tests, the presence of mutations suitable for targeted therapies is investigated by detecting tumor DNA circulating in the blood. Liquid biopsies prevent redoing biopsy, especially in patients who have undergone biopsy before but do not have enough tissue.

After these mutation analysis, chemotherapy is preferred in patients who are not suitable for targeted therapy. In recent years, an important development has been in immunotherapies. In other words, drugs that eliminate a kind of insensitivity or blindness to the cancer cell that emerges in the defense system of the individual with cancer created excitement after 2011 and after successful results, the FDA announced that it was used for skin cancer, malignant melanoma, non-small cell lung cancer, kidney cancer, It is approved for the treatment of Hodgkin lymphoma, head and neck cancers and bladder cancer. Today, the use of these drugs is recommended in patients who used the first series of chemotherapy and did not get an adequate response or whose disease progressed in the following period despite the response. Research on its use in first-line treatment in patients newly diagnosed with cancer continues. The first studies have been published and found promising that success can be achieved either alone or in combination with chemotherapy.

The most important handicaps of these treatments are that they are expensive. It could not be included in the scope of reimbursement by many countries due to the fear that they are expensive and that they will pose a threat to the country's economy.

Cancer does not only differ between species. Even in individuals with cancer, the same type of cancer differs. Each individual's resistance to treatments and accompanying diseases are different. In particular, the increase in treatment options and differences in tumor types have led to the selectivity of individual differences in cancer treatment and the development of individual-specific treatments.