Influence of irradiation on neutrophilic granulocyte function.
BACKGROUND
Neoadjuvant radiotherapy is a common treatment modality for patients with Stage II and III rectal carcinoma but, after surgery, often is complicated by local infections. To define a possible influence of radiotherapy on neutrophilic granulocytes in the neighborhood of tumor cells, the authors investigated their function in vitro.


METHODS
Density gradient-purified granulocytes from healthy donors were used for all tests. These cells were cocultured with the colon carcinoma cell line HRT-18 and irradiated. Their function was assessed by measuring luminol-enhanced chemiluminescence and migration against the chemoattractant formyl-methionyl-leucine-phenylalanine.


RESULTS
Although irradiation decreased, the addition of tumor cells increased reactive-oxygen species release in granulocytes, which was enhanced further by phorbol myristate acid (PMA), even after several hours. All contacts with tumor cells, however, caused immediate radical release that was inversely proportional to the radiation dose. Naïve and irradiated cells were stimulated further by PMA. Migration of granulocytes clearly was inhibited by tumor cells and irradiation, whereas the depth of invasion was enhanced by higher doses of radiation.


CONCLUSIONS
The current data show clearly that the influence of radiotherapy on local defense against colorectal carcinoma is limited and cannot explain the increased rate of infectious complications.
De Vries
A
A
Department of Radiotherapy, Innsbruck University Hospital, Anmichstrasse 35, A-6020 Innsbruck, Austria.
Holzberger
P
P
Kunc
M
M
Hengster
P
P
D002277:Carcinoma / Q000473:pathology* / Q000532:radiotherapy; D018929:Cell Culture Techniques; D002465:Cell Movement / Q000528:radiation effects*; D003110:Colonic Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D006098:Granulocytes / Q000502:physiology* / Q000528:radiation effects*; D006801:Humans; D007239:Infections / Q000209:etiology; D020360:Neoadjuvant Therapy / Q000009:adverse effects; D010587:Phagocytosis; D010703:Phorbol Esters / Q000494:pharmacology; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D017382:Reactive Oxygen Species; D014407:Tumor Cells, Cultured
D010703:Phorbol Esters; D017382:Reactive Oxygen Species; C119222:phorbol-12-myristate