Preliminary Results of Proton Radiotherapy for Esophageal Cancer

Reviewer: James M. Metz, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 22, 2007

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Presenter: Suwen Liu
Presenter's Affiliation: Wanjie Proton Therapy Center, Zibo, China
Type of Session: Scientific

Background

China has the highest incidence of esophageal cancer in the world with a rate of 479 per 100,000 people. Radiation therapy plays an important role in the treatment of this disease. However, standard radiation therapy is limited by the toxicity of treatment, particularly when combined with chemotherapy.  Proton therapy may reduce exposure of normal tissues such as the lungs, heart, and spinal cord and hence reduce the toxocity of treatment when compared to conventional radiation therapy.

Materials and Methods

  • Between 12/04 and 4/06, 6 patients with esophageal cancer were treated at the Wanjie Proton Therapy Center.
  • All patients were male and the median age was 65 years.
  • All patients had an ECOG performance status of 0-1
  • The location consisted of upper esophagus (1), mid esophagus (3), lower esophagus (1), and abdominal esophagus (1).
  • The proton therapy portals were designed to extent 3-4 cm beyond the tumor volume.
  • Patients received 54-66 CGE in 1.8-2.0 CGE fractions
  • The range of follow up is 12-24 months

Results

  • Esophagitis was grade 0-1 for 4 patients and grade 2 for 2 patients.
  • There was no incidence of radiation induced pnuemonitis
  • There was no incidence of esophageal ulcers
  • One patient developed a recurrence of the primary tumor at 12 months after treatment
  • The overall survival at 1 year is 100%

Author's Conclusions

  • Proton therapy is an effective method of treatment for patients with esophageal cancer
  • Acute toxicity is lower then conventional radiation therapy
  • The optimal dose of radiation therapy to be used with protons still needs to be defined due to the much lower dose of normal tissue exposure to radiation with proton therapy

Clinical/Scientific Implications

There are very limited reports of proton therapy being used to treat GI malignancies in the medical literature. The esophagus may be an important target for proton therapy because of the reduced normal tissue exposure to radiation and need to combine radiatio with other treatment modalities. This study, although very preliminary with small numbers gives us some understanding of the tolerability of this approach. However, the doses of radiation utilized were not consistent and the use of chemotherapy was not consistent in this study, which are very important parameters to define as we move forward with the evaluation of proton therapy in esophageal cancer. We look forward to future reports with greater numbers of patients and longer follow up.