The protection of the small intestine and colon from carbon ion particle irradiation by means of Gore-Tex soft tissue patches for patients with pelvic tumors

Reporter: John P. Plastaras, MD, PhD
Abramson Cancer Center of the University of Pennsylvania
Ultima Vez Modificado: 13 de octubre del 2006

Presenter: Shigeru Yamada, MD
Affiliation: Division of Radiation Medicine, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
Other Authors:
Tadashi Kamada, Ryusuke Hara, Hirotoshi Kato, Shigeo Yasuda, Masayuki Kano, Shingo Kato, Reiko Ima, Hirohiko Tsujii

Background

  • Recurrent pelvic tumors are challenging to treat due to close proximity of bowel that may lie directly adjacent to tumors of the pelvic side-wall or in the sacral hollow
  • Carbon ion radiotherapy offers two advantages over photon radiotherapy:
  • a higher relative biological effectiveness (RBE)
  • no exit dose (similar to protons) as dose is deposited preferentially in a Bragg peak
  • Because the dose decreases from a maximum to zero in the span of a few millimeters at the distal edge of a carbon ion treatment beam, the authors surgically placed Gore-Tex spacers between tumors and bowel prior to carbon ion radiation

Material and Methods

  • 13 patients with pelvic tumors (8 recurrent rectal cancer, 1 recurrent colon cancer, 2 pelvic sarcomas, and 2 ovarian cancer)
  • 8 pelvic side wall
  • 3 pre-sacral region
  • 2 colorectal anastomosis
  • Expanded polytetrafluoroethylene (Gore-Tex soft-tissue patch) was placed surgically between the pelvic tumors and intestines
  • Carbon Ion Radiation:
  • Mean time between surgery and radiation was 14.5 days (range 10 to 39 days)
  • Doses ranged from 52.8 to 73.6 GyE (Gray equivalent)
  • 4.2 GyE fractions
  • Mean follow-up = 7.2 months (range 2 to 20 months)

Results

  • Complications: 2 patients had adhesive ileus after operation and were treated conservatively
  • All patients completed the planned radiation treatment
  • Toxicity: There were no grade 3 toxicities observed. There were relatively few and mild toxicities
  • Local Control:
  • 93% at 1 year, 83% at 2 years, 79% at 3 years
  • By Dose: 70% with 67.2 GyE, 87% with 70.4 GyE, and 87% with 73.6 GyE
  • Survival (3 year):
  • By Dose: 36% with 67.2 GyE, 61% with 70.4 GyE, and 81% with 73.6 GyE

Author's Conclusions

  • Gore-Tex is a safe and effective implant material to prevent intestinal damage from carbon ion radiation in the treatment of pelvic tumors

Clinical and Scientific Implications

  • Insertion of inert material between tumor and organs at risk can provide a buffer for dose fall off distal to target structures when using particle therapy. This principle should in theory also work with proton radiotherapy.
  • There appears to be a dose response when treating pelvic tumors with carbon ion radiotherapy, however, it is unclear why patients received various doses in this study
  • There was no increased incidence of infection experienced in this series. There was also minimal delay of two weeks starting radiation after the implant was placed

Blogs

Don't Assume You Understand
by Bob Riter
July 29, 2015