The case for external beam radiotherapy of certain adenocarcinomas of the prostate

Radical surgery and definitive X-irradiation have much in common in the treatment of carcinoma of the prostate. They are both local modalities and, therefore, to a certain extent, limited by their ability to encompass the full extent of disease within or in continuity with the target organ. Surgery is advantageous because if the entire neoplasm is resected, then the patient is cured. It is disadvantageous because of the inability to determine in many cases the true extent of the tumor and the significant probability that the surgical excision may transect extracapsular neoplasm. Radiotherapy has the advantage of being able to encompass a more generous target volume than surgery, making it less sensitive as to whether or not the capsule has been penetrated. Radiotherapy is disadvantaged because it is impossible to know, except on a statistical basis, whether or not all of the cells have been truly sterilized. However, as the tumor burden increases, the ability of external beam irradiation alone to sterilize the tumor diminishes. Certain adjunct treatments, such a radioactive implant boost, sensitization by chemotherapeutic agents, radiosensitization by hyperthermia, or boost by neutron therapy may increase the probability of sterilizing the more bulky neoplasms. Because of the lower morbidity expected from skillfully executed radiotherapy, the treatment may be implemented in situations of relative low grade malignancy which might not warrant radical surgery. In view of these considerations, recommendations for local external beam radiotherapy are made