Successful oncological standard procedures can only be replaced by new methods if their value has been proven by long-term results. Laparoscopic tumor resections with curative intention have to be considered experimental, especially because long-term results are not yet available. These operations require two preconditions: 1) the oncological quality of tumor resection must be assessed by special methods of pathohistological examinations; and 2) long-term follow-up care must be guaranteed. In most cases, these preconditions are only secured within clinical trials.