TY - JOUR T1 - Radioimmunotherapy prevents local recurrence of colon cancer in rats JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1552 LP - 1552 VL - 50 IS - supplement 2 AU - Gabie De jong AU - Robert Bleichrodt AU - Sandra Heskamp AU - Frits Aarts AU - Thijs Hendriks AU - Wim Oyen AU - Otto Boerman Y1 - 2009/05/01 UR - http://jnm.snmjournals.org/content/50/supplement_2/1552.abstract N2 - 1552 Objectives Since radioimmunotherapy (RIT) is particularly suited to treat small lesions, the objective of this study was to determine the potential role of RIT as an adjuvant after colon cancer surgery. Methods In male Wag/Rij rats an anastomosis was constructed after intraluminal injection of 2 x 106 CC531 tumor cells. The biodistribution of 111In-labeled anti-CC531 antibody MG1 after intraperitoneal administration was assessed in this model. Subsequently, the therapeutic efficacy of 177Lu-labeled MG1 (74 MBq per rat) was compared with that of the carrier only (n=13). RIT was administered either at the day of surgery (D0, n=13) or 5 days postoperatively (D5, n=13). Primary endpoint was peri-anastomotic tumor growth 28 days after surgery (Figure 1). Results 111In-labelled MG1 preferentially accumulated in peri-anastomotic CC531 tumors (2.5 ± 0.2 %ID/g), while uptake in normal organs did not exceed 1%ID/g. Mortality rate due to surgery was 1/54 rats. No macroscopic or microscopic peri-anastomotic tumor growth was found in 8/11 rats in the D0-group and 11/13 rats in the D5-group, while in the control group 11/13 rats did had peri-anastomotic tumors (P=0.011 and P=0.001 versus control groups respectively). RIT resulted in transiently lower body weight in both treatment groups (P<0.05), compared to the control group. However, no other signs of clinical discomfort were registered. Conclusions This study indicates that RIT can be an effective adjuvanttreatment modality to prevent local recurrence afterresection of colon cancer. ER -