Intraoperative radiotherapy for resectable extrahepatic bile duct cancer

Vascular and nerval damage after intraoperative radiation therapy of the liver hilum in a large animal model

It has been demonstrated that intraoperative radiotherapy is a therapeutic option for patients suffering from perihilar cholangiocarcinoma. Aim of our study was to investigate vascular and nerve damages after irradiation of the liver hilum in a pig model. Twenty-four pigs underwent central bile duct resection followed by biliodigestive anastomosis. Nine pigs underwent this surgical procedure alone (group 1). Ten pigs were treated with additional intraoperative radiation therapy (IORT) of 20Gy to the liver hilum (group 2). And five pigs received operation and IORT with 40Gy to the area of anastomosis (group 3). Six weeks after operation and treatment the animals were sacrificed and histopathological examination was performed. Histology showed no vascular or nerve damage in non-irradiated perihilar tissue. Significant changes of nerve structures occurred, as well as vascular damage in large and even more in small hilar arteries in the irradiated neighboring liver tissue. In detail for small hilar arteries: intima proliferation (p ≤ .0001), endothelial swelling (p ≤ .0001), fibrinoid arterial wall necrosis (p ≤ .0001), and arterial thrombosis (p = .0079) were detected. Venous vessels did not show significant dose dependant cell damage. Overall, 20Gy as a single dose application during operation showed similar damage to vessels and nerves compared to 40Gy. A radiation dosage of 20Gy seems to be sufficient to induce necrosis due to vascular and nerve damage in potential malignant liver tissue with acceptable damage to surrounding tissue. Perineural invaded tumor cells might be diminished due to IORT.

Biliodigestive anastomosis after intraoperative irradiation in swine

A large animal model was established to investigate the feasibility and suitable dosage of intraoperative radiation therapy (IORT) to the hepatic hilum before biliary-enteric anastomosis is performed. Twenty-two Pietrain Hampshire pigs underwent gallbladder and proximal bile duct resection followed by IORT using 20-40 Gy and performing biliary-enteric anastomosis. In the follow-up period of 56 days, pigs developed dose-dependent complications like stenosis of the biliary-enteric anastomosis. Results demonstrate that IORT of the liver hilum up to 20 Gy is safe with acceptable early complications in the presented animal model. The porcine biliary-enteric anastomosis can tolerate intraoperative irradiation up to a dosage of 40 Gy without disruption.

A study of radiotherapy modalities combined with continuous 5-FU infusion for locally advanced gastrointestinal malignancies

AIM

We describe the feasibility of combining infusional 5-fluorouracil (5-FU) with intraoperative radiation therapy (IORT).

METHODS

Patients with surgically resectable locally advanced gastrointestinal cancers were treated concurrently during surgery with IORT and a 72 h infusion of 5-FU. Patients without previous external beam radiation therapy (EBRT) were subsequently treated with EBRT (40-50Gy) concurrent with a 21-day continuous infusion of 5-FU. Pancreatic, gastric, duodenal, ampullary, recurrent colorectal, and recurrent anal cancer were included.

RESULTS

During IORT/5-FU, no chemotherapy-related grade III or IV hematologic or gastrointestinal toxicity was noted. Post-surgical recovery or wound healing was not affected. One of nine patients who received post-operative radiation required a treatment break. During follow-up, there were more complications in patients with pelvic tumours, especially those with previous radiation. Nine patients have had local and/or local regional recurrences, two of these in the IORT field.

CONCLUSIONS

Treatment with a combination of IORT and 5-FU followed by EBRT and 5-FU is feasible. However, long-term complications may be increased in previously irradiated recurrent pelvic tumours.

Intraoperative radiation therapy in the multimodality approach to hepatobiliary tract cancer

IOERT is a reasonable option to consider in patients who have biliary tract cancers above AJCC or Bismuth stage I disease. Inherent resistance of biliary tract cancer cells to ionizing radiation would indicate that IOERT alone would not eradicate most of the tumor clonagen. EBRT (either preoperatively or postoperatively) should be used in combination with IOERT at experienced institutions that have access to both modalities. The single IOERT dose ranges are 10 to 20 Gy [55,67], whereas the EBRT dose ranges from 45 to 50 Gy in 25 to 28 fractions [67]. The most common energy level used is 8 MeV or less. In addition, IOERT port sizes of less than 6 cm in diameter, and often 4 cm or less, are recommended. Finally, intraoperative reconstruction of severely damaged blood vessels may decrease the clinical manifestation of radiation-induced injury to vessels [68].