Experimental study of radioimmunotherapy versus chemotherapy for colorectal cancer.
BACKGROUND
Radioimmunotherapy (RIT) has been shown to reduce the incidence of local recurrence of colorectal cancer in an experimental model. The aim of the present study was to investigate the survival benefit of RIT compared with chemotherapy.


METHODS
An anastomosis was constructed in male Wag/Rij rats after intraluminal injection of CC531 tumour cells. The therapeutic efficacy of (177) Lu-labelled MG1 (single intravenous dose of 300 MBq/kg, n = 20) was compared with that of 5-fluorouracil-based chemotherapy (6 weekly cycles administered intraperitoneally, n = 20) and no treatment (n = 20). The primary endpoint was survival. Toxicity was monitored by bodyweight measurement.


RESULTS
Both chemotherapy and RIT affected bodyweight, but the weight of animals in the RIT group remained significantly higher than in the chemotherapy group (median slope of bodyweight plot 0·48 versus 0·30 g/day; P < 0·001). Kaplan-Meier analysis showed that overall survival in the RIT and chemotherapy groups was significantly better than that in the control group (50 and 46 per cent versus 25 per cent respectively after 170 days; P = 0·024 and P = 0·029). Survival after treatment with RIT did not differ from that after chemotherapy (P = 0·911).


CONCLUSIONS
RIT is as effective as chemotherapy in experimental colorectal cancer.
Department of Surgery, Division of Oncology and Abdominal Surgery, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. g.dejong@chir.umcn.nl
G M
GM
de Jong
R P
RP
Bleichrodt
A
A
Eek
W J G
WJ
Oyen
O C
OC
Boerman
T
T
Hendriks
D000818:Animals; D000911:Antibodies, Monoclonal; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy*; D008187:Lutetium / Q000627:therapeutic use*; D008297:Male; D009368:Neoplasm Transplantation; D004369:Pentetic Acid / Q000627:therapeutic use; D016499:Radioimmunotherapy / Q000379:methods*; D011868:Radioisotopes / Q000627:therapeutic use*; D051381:Rats; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D011868:Radioisotopes; D008187:Lutetium; D004369:Pentetic Acid