Radiotherapy-Induced Senescence and its Effects on Responses to Treatment

Radiotherapy is still a treatment of choice for many malignancies, often in combination with other strategies. However, its efficacy is limited by the dose that can be safely administered without eliciting serious side-effects, as well as the fact that recurrence is common, particularly in large tumours. Combining radiotherapy with drugs that could sensitise cells to radiation and/or reduce the factors that promote the recovery of the surviving cancer cells is a promising approach. Ionising radiation has been shown to induce senescence and the accumulation of senescent cells creates a microenvironment that facilitates neoplastic growth. This provides a rationale to test the addition of anti-senescent drugs, some of which are already available in the clinic, to radiotherapy protocols. Here, we discuss the relevance of radiotherapy-induced senescent cell accumulation and the potential interventions to minimise its negative effects.