BOGEY OF IMMUNOSUPPRESSIVE ACTION OF LOCAL RADIOTHERAPY

Reasonable steps should be taken to maintain the cancer patient''s immune capacity at as high a level as possible. However, overenthusiasm for maintaining immunity in cancer can easily lead to therapeutic nihilism, since all of the available methods except perhaps surgery that are capable of destroying cancer, can be immunosuppressive. The prime duty of thetherapist is to destroy as much tumor as possible; if this requires compromising immunity, then this has to be accepted. The rarity of spontaneous regressions shows that immunity by itself is ineffective in the face of clinical cancer and hypothetical considerations of immunity do not justify under-treatment. These comments apply particularly to chemotherapy where clinically evident immunosuppression frequently is evident. However, they have been extended to radiotherapy, though the evidence that this form of treatment is significantly immunosuppressive, unless very large volumes are irradiated, is not convincing. There is no data that justifies equating a decrease in the number of leukocytes that form rosettes with sheep red cells with the existence of an immune-suppressed state. The claim frequently is made, based on in vitro tests with blood cells and on skin reaction, that patients with malignant disease are inherently immunosuppressed and that this is a contributing factor in the etiology of their disease. The facts are different; in general only some patients with advanced cancer show an immune deficit and the immune reactivity is almost invariably within the normal range for patients with early cancer when proper age-match controls are used. While in general radiotherapy may not cause significant immune suppression, it still may be possible to augment the effects of radiotherapy by boosting the magnitude of the immune reaction of the patient to his tumor.