A novel approach for treatment of unresectable pancreatic cancer: design of radioactive stents and trial studies on normal pigs.

PURPOSE

Patients diagnosed with pancreatic cancer typically have a poor prognosis. The aims of these studies were to design radioactive stents and to evaluate the feasibility and safety of the stents in animals.

EXPERIMENTAL DESIGN

To combine the effects of stents and brachytherapy, plastic stents with inserted iodine-125 seeds were designed and tested in 18 normal pigs. The pigs were divided into five groups on the basis of radiation dose. The estimated radiation dose at a 5-mm radial distance from the axis of the seeds was 50 Gy in group A, 100 Gy in group B, 150 Gy in group C, and 200 Gy in group D, with four pigs in each group. In the control group (n = 2), the same plastic stents with non-radioactive seeds were implanted in the pancreatic duct.

RESULTS

The procedures were successfully done on 14 of 18 (78%) pigs, whereas pancreatic duct perforation occurred in four pigs (22%). The thickened wall of the dilated pancreatic duct was clearly observed in the control group. However, the normal morphologic structure of the pancreatic duct wall disappeared in the experimental groups. Histopathologic examination revealed that the stents were surrounded with necrotic tissues and lateral fibrous tissues. During the follow-up period, the width of outside fibrous tissues gradually increased.

CONCLUSIONS

These results indicate that the radioactive stents are safe in all dose groups, and it is feasible to design a special radioactive stent for each patient according to the size, shape, and position of the pancreatic tumor.