Since cancer cells proliferate faster than normal cells, DNA replication is therefore significantly greater in cancer cells. Many chemotherapeutic agents used in cancer treatments hinder cancer cell replication by inducing DNA breaks.
Cells repair DNA by a variety of mechanisms, and cancer cells do it even more than normal cells, which results in a lessening of the efficiency of cancer therapies. This loss in efficiency necessitates the use of high concentrations of chemotherapeutics in order to obtain a satisfactory inhibition of cancer proliferation.
These substances are, however, very toxic and have damaging side effects, which is why hindering tumor cell proliferation is an essential non-optimized oncology need.