While minimal access procedures such as laparoscopy and thoracoscopy are now widely practiced for diagnosis, staging, and treatment of cancer in adults and children, this practice in children has not been proved safe or effective. To determine the role of laparoscopy and thoracoscopy in the management of children with cancer, we will compare the utility of these minimal access procedures to conventional procedures. Because childhood tumors are relatively rare compared to adult tumors, and because the procedures we perform in children with cancer, e.g., lymph node sampling, are similar regardless of the tumor type, we will study patients with a variety of common pediatric malignancies rather than focus on a single entity. Thus, within the context of a large, multi-center, cooperative. group, we will have ample patients to study the techniques in question. We will learn whether these minimal access procedures are feasible and can be carried out safely in children without compromising patient care, survival, or the disease protocol on which they are being treated. We will compare: the procedural and overall costs, operative time, postoperative analgesic requirements, the length of the postoperative stay and return to unrestricted activity, the delay in initiating postoperative chemotherapy and/or radiotherapy, the acute and chronic morbidity, and the effect (if any) on outcome (survival) of minimal access surgery versus open surgery. We will also compare the findings of the preoperative images (often used for staging) with the findings at minimal access surgery and open surgery to determine any differences in the two techniques regarding their accuracy for staging. Comparing minimal access surgery versus open surgery, we will study the commonly performed procedures of: diagnostic tumor biopsy (abdomen and chest), liver biopsy, lymph node sampling (abdomen and mediastinum), lung biopsy, and, in selected cases, tumor or organ excision. Using patients treated by members of the surgical discipline of our cooperative group who are competent at conventional and minimal access surgery, we plan to randomize at least 240 children annually in each category (laparoscopy and thoracoscopy) for each of three years. The data will be stratified according to disease and the procedure performed. Analysis of our data will permit us to determine the role of minimal access surgery in the management of children's cancer.