RATIONALE: Antiemetic drugs may help to reduce or prevent vomiting in patients treated with radiation therapy. It is not yet known if ondansetron is more effective with or without dexamethasone in preventing vomiting caused by radiation therapy.

PURPOSE: This randomized phase III trial is comparing how well ondansetron works with or without dexamethasone in preventing vomiting in patients with cancer who are receiving radiation therapy to the upper abdomen.

OBJECTIVES:

• Compare the effectiveness of ondansetron with or without dexamethasone as prophylaxis for radiation-induced emesis and nausea in patients receiving upper abdominal radiotherapy.
• Compare toxicity of these regimens in these patients.
• Compare quality of life of patients treated with these regimens.

OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to radiotherapy field description (whole abdomen and pelvis vs partial abdomen and pelvis vs partial abdomen only). Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients receive oral ondansetron twice daily and oral dexamethasone daily for 5-7 days concurrently with the first 5 fractions of radiotherapy.
• Arm II: Patients receive oral ondansetron twice daily and oral placebo daily for 5-7 days concurrently with the first 5 fractions of radiotherapy.

Treatment continues in both arms in the absence of disease progression or unacceptable toxicity.

Quality of life is assessed at baseline, prior to starting radiotherapy if more than 5 days since randomization, prior to the 5th and 15th fractions of radiotherapy, and 1 month after completion of radiotherapy.

Patients are followed at 1 month.

PROJECTED ACCRUAL: A total of 100-200 patients (50-100 per arm) will be accrued for this study.

DISEASE CHARACTERISTICS:

• Cancer patients who are scheduled to receive radiotherapy within the next 3 weeks

  • Total dose at least 2,000 cGy delivered in at least 15 fractions
  • 1 fraction per day, 5 days per week
  • Treatment field to include an area of at least 80 cm2 in the anterior/posterior direction encompassing the upper abdomen
• At risk of developing radiation-induced emesis
• No emesis (retching and/or vomiting) or nausea with severity greater than 2 within the past week

PATIENT CHARACTERISTICS:

Age:

• 16 and over

Performance status:

• ECOG 0-3

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• No jaundice
• No moderate to severe hepatic dysfunction

Renal:

• Not specified

Gastrointestinal:

• No active peptic ulcer
• No lactose intolerance

Other:

• No concurrent condition or illness that contraindicates corticosteroids, serotonin antagonists, or prochlorperazine (e.g., diabetes mellitus)
• No prior unusual or allergic reaction to a serotonin antagonist (ondansetron, dolasetron, or granisetron), corticosteroid, or prochlorperazine
• No condition that would preclude accessibility to treatment or follow-up
• Able and willing to complete diary and quality of life questionnaires in either English or French
• Able to swallow

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• At least 1 week since prior cytotoxic therapy
• No concurrent cytotoxic therapy

Endocrine therapy:

• No concurrent corticosteroids other than topical or inhaled preparations

Radiotherapy:

• See Disease Characteristics
• At least 1 week since prior radiotherapy
• No concurrent cranial radiotherapy

Surgery:

• Not specified

Other:

• At least 2 days since prior medication with antiemetic intent