Timing of Adjuvant Radioimmunotherapy after Cytoreductive Surgery in Experimental Peritoneal Carcinomatosis of Colorectal Origin

Abstract

The efficacy of adjuvant RIT after CS for the treatment of PC of colonic origin decreases when the administration of the radiolabelled MAbs is postponed. This study shows that adjuvant RIT should be given as early as possible after surgery.

Dose Deposits from 90Y, 177Lu, 111In, and 161Tb in Micrometastases of Various Sizes: Implications for Radiopharmaceutical Therapy

“…The predicted dose would be 104 Gy in a 1-mm metastasis, 24.5 Gy in a 100-mm micrometastasis, and 3.9 Gy in a 10-mm single tumor cell. Although small tumors are more radiosensitive than macrometastases (10,11), the low dose delivered by 177 Lu to isolated cells might not be sufficient to destroy them all. However, the dose delivered by a hypothetical 161 Tb-labeled somatostatin analog (with the same tumor affinity) would be 1.8 times higher in a 100-mm micrometastasis (44.5 Gy) and 3.6 times higher in a 10-mm single cell (14.1 Gy) (Table 3).…”

“…Moreover, hypoxia increases resistance to radiation. Experimental data in rodents also showed better efficacy on microscopic metastases (10,11).…”

Hyperthermia and Fibrinolytic Therapy Do Not Improve the Beneficial Effect of Radioimmunotherapy Following Cytoreductive Surgery in Rats with Peritoneal Carcinomatosis of Colorectal Origin

“…10 The effect was most explicit when RIT treatment was administered immediately following surgery, as compared to 4 or 14 days after surgery. 11 In rats with intraperitoneal CC531 tumors, RIT was found to be at least as effective as HIPEC in terms of survival after CS, and RIT induced fewer side effects than the adjuvant treatment with HIPEC. 12 These experiments suggest that RIT is a promising therapeutic approach to ameliorate treatment of PC.…”

Emerging Trends for Radioimmunotherapy in Solid Tumors

“…In a model with resected peritoneal carcinomatosis, the 177 Lu-MG1 antibody improved survival after cytoreductive surgery as compared to chemotherapy. 44, 45 Koppe et al also demonstrated the efficacy of RIT in peritoneal carcinomatosis after cytoreductive surgery. 49 In these studies, rats were first injected intraperitoneally with 2 · 10 6 CC-531 cells and tumors were allowed to grow for 14 days.…”

“…However, several recent studies have modeled minimal residual and metastatic disease in rat and mouse models and evaluated the efficacy of RIT. [38][39][40][41][42][43][44][45] Some of the models of minimal disease and the RIT strategies employed in these studies are schematically described in Figure 1.…”