BCM mechanisms in clinical radiotherapy

Photon radiation still remains one of the mainstays in the local control of many solid tumours. An appreciation of its deficiencies stimulated several studies to evaluate the reasons for its failures and attempts at enhancement of the radiotherapeutic effect. Chemical sensitisation, drug potentiation, enzymolisis have all been employed during the last three decades with diverse degrees of success. The underlying biological mechanisms involved in a tumour host-radiation interaction and its reflection in the radio-responsiveness of a tumour in vivo were examined. It is observed that any enhancement of radio-therapeutic effect can be obtained only if these biological parameters are evaluated in the individual tumour and host and the use of the potentiator or sensitiser rationalised to the specific biological situation. Empirical combinations are unwise as they could carry a potential for harm. (auth.)