DISEASE CHARACTERISTICS: Histologically confirmed advanced malignancy involving the peritoneal cavity, excluding leukemia and lymphoma Patients with ovarian cancer must have received prior standard therapy Predominantly small tumor metastases less than 1.0 cm in diameter including: Ovarian cancer with epithelial histology Other gynecological tumors Breast cancer Gastric cancer Colorectal cancer Appendiceal cancer Pancreatic cancer Unknown primary cancer Other malignancies with predominantly intraperitoneal manifestation No extensive intraperitoneal adhesions that cannot be easily lysed laparoscopically or by laparotomy No symptomatic disease outside the peritoneal cavity Asymptomatic disease outside the peritoneum considered (e.g., bone lesions)