Hyperfractionated abdominal reirradiation for gastrointestinal malignancies

Area of Science:

• Oncology
• Radiation Oncology
• Gastrointestinal Oncology

Background:

• Assessing the role of abdominal reirradiation for recurrent or new primary gastrointestinal (GI) malignancies.
• Evaluating a hyperfractionated, accelerated reirradiation regimen (39 Gray in 26 twice-daily fractions) for abdominal tumors, a technique commonly used in pelvic cases.

Purpose of the Study:

• To determine the toxicity and efficacy of abdominal reirradiation using a hyperfractionated, accelerated approach.
• To analyze patient, tumor, and treatment characteristics associated with overall survival (OS) and local progression-free survival (LPFS).

Main Methods:

• Retrospective review of 24 patients who received abdominal reirradiation between 2000 and 2017.
• Calculation of OS and LPFS using Kaplan-Meier method.
• Univariate analysis using Cox proportional hazards model to identify factors associated with OS and LPFS.

Main Results:

• The majority of patients (46%) had pancreatic adenocarcinoma; other GI malignancies were also included.
• The median reirradiation dose was 39 Gy in 26 twice-daily fractions, with a median interval of 28 months between radiation courses.
• One-year OS was 50%, median OS was 14 months, and 1-year LPFS was 38%. Palliative intent was associated with decreased OS, while colon adenocarcinoma showed potential for increased LPFS.
• 54% of patients experienced acute side effects, mostly Grade 1-2, with one G3 nausea and one G4 bleed reported.

Conclusions:

• Hyperfractionated, accelerated abdominal reirradiation is relatively well-tolerated but offers limited local control for recurrent or secondary GI malignancies.
• Reirradiation may have a role in managing these patients, but alternative strategies for increasing biologically effective dose warrant further investigation.