Radiosensitivity is the degree of shrinkage of a tumour that occurs following radiation delivery. It depends on multiple factors within the tumour cell line, such as the cell of origin. The variable radiosensitivity was first noted in 1906 by Bergonie and Tribondeau with experiments on rat testis. The germinal epithelium was noted to be radiosensitive, whereas the supportive Sertoli cells were radioresistant. They hypothesised that cells with reproductive capability were more sensitive than differentiated cells.
Radiocurability is the ability of radiotherapy to cause the local eradication of a malignancy. Radiocurability does not refer to overall survival as patients may develop distant metastases away from the treated site.
Relation of radiocurability and radiosensitivity
Radiation responsiveness is not always a good indicator of radiocurability. Many tumours are radiosensitive and may show near complete response to radiotherapy, but relapse after completion of treatment. Less commonly, some well differentiated tumours may respond slowly to radiotherapy but ultimately be cured with radiation alone.
- Old R08: Radiation Response Modifiers