Cyproheptadine and Megestrol in Preventing Weight Loss in Children With Cachexia Caused By Cancer or Cancer Treatment

OBJECTIVES: * Determine the efficacy of cyproheptadine in preventing further weight loss in children with cancer or cancer treatment-related cachexia. * Determine the efficacy of megestrol in preventing further weight loss in patients who don't respond to cyproheptadine. * Determine how these drugs affect body protein and fat levels in these patients. OUTLINE: Patients receive oral cyproheptadine twice daily for 4 weeks in the absence of unacceptable weight loss or toxicity. Patients that present with weight loss after 4 weeks receive oral megestrol daily for 4 weeks in the absence of unacceptable weight loss or toxicity. Patients responding to either cyproheptadine or megestrol may continue treatment at the discretion of the treating physician. Patients are followed at 4 weeks. PROJECTED ACCRUAL: A total of 70 patients will be accrued for this study.