Best of ASCO 2015 Istanbul: Immunotherapy Is the Topic Again

The Best of ASCO meeting began today in Istanbul, reviewing the most important topics that change our clinical practice presented at the ASCO 2015 Congress, the world's leading cancer event, held in Chicago in the last week of May. As expected, one of the meeting's main topics is immuno-oncology and immunotherapy!

While traditional chemotherapy aims to kill cancer cells directly, immunotherapy aims to activate the immune system so that cancer is recognized as foreign in the body and controlled or eliminated by the immune system as if cancer cells were harmful microorganisms.

T cells play a key role in cancer immunotherapy. They must pass through certain stages to recognize cancer cells, become activated, and multiply. Various signals are needed to activate T cells. We can explain the activation and deactivation of these cells and other key immune cells using a car analogy. Imagine that our immune system is a car: first we need to start the engine, but the car does not start simply by turning the key; you also need to press the accelerator. At the cellular level, some signals act like an accelerator and activate our immune system, while others act like brakes and stop it. Through certain mechanisms, cancer cells send braking signals to the immune system, thus escaping it and continuing to multiply and spread. These new-generation immunotherapy drugs have ushered in a new era in cancer treatment by blocking the signals that brake the immune system.

Among the most discussed and anticipated topics at the Best of ASCO Istanbul meeting, which began today, are newly developed immunotherapy drugs (particularly ipilimumab, nivolumab, and pembrolizumab) and what they promise us. We discussed these drugs in detail in the articles published on our website this week. However, it is useful to emphasize this point: because their mechanisms of action differ, the benefits of immunotherapies may emerge later than those of conventional chemotherapy, but long-term response rates are better with immunotherapy, and side effects are more manageable than with conventional chemotherapy. For these reasons, physicians and patients choosing these drugs need to be patient about the expected benefits.