What does chemoresistance mean?

Author:  Gesche Tallen, MD, PhD, Editor:  Maria Yiallouros, Reviewer:  Prof. Dr. med. Dr. h.c. Günter Henze, English Translation:  Hannah McRae, Last modification: 2015/04/27 https://kinderkrebsinfo.de/doi/e75237

Some cancer cells harbour mechanisms that can protect them from and help them repair a damage caused by chemo- or radiotherapy. As a result, they will continue to divide and spread and even pass these escape mechanisms on to their daughter cells, despite the treatment given. Cancer specialists call this behaviour "intrinsic resistance".

Other cancer cells can learn how to escape from damage after they have been treated once or repetitively with a certain agent. During cell division, these acquired escape mechanisms can also be passed on the next generation of cancer cells. Taken together, once a cancer cell has figured out how the damaging agent works, chemo- or radiotherapy, respectively, might lose their anticancer effects (so-called "extrinsic resistance").

The mechanisms of resistance exerted by some cancer cells include, for example, the alteration of processes that regulate the uptake and the metabolism of the chemotherapeutic agent or the way these cells respond to stress.

In order to prevent mechanisms of resistance and, thus, non-response to treatment to occur, the current standard chemotherapy regimens use a combination of multiple agents that have different mechanisms of action and are given alternately (polychemotherapy).

Many of the malignant diseases in children and teenagers are sensitive to both chemo- and radiotherapy. Therefore, feasible combinations of these treatments are backbones of the different therapy-optimising protocols currently applied in many treatment centres.