Purpose: The significance of investigations of thoracic cavities as well as pleural biopsy and intrathoracic washing cytology through transdiaphragmatic thoracoscopy for stage IIIc ovarian cancer with diaphragmatic metastases was assessed as a prospective pilot study.

Subjects and Methods: Eligibility criteria were established to include patients with stage IIIc ovarian cancer in whom pleural effusions were not detected preoperationally, but prominent diaphragmatic metastases were observed when the abdomen was opened and those who submitted consent. Transdiaphragmatic thoracoscopy was performed after diaphragm stripping. Then, biopsy of the lesion suspected to be disseminated or the plural membrane of the thoracic opening was performed followed by washing cytology using physiological saline.

Results: Ten subjects were enrolled. Disseminated lesions were observed on plural membranes, and positive results were obtained in biopsy and washing cytology in 3 subjects. In addition, positive results were seen with biopsy alone in 2 subjects and with washing cytology alone in 2 subjects. Hence, a total of 7 subjects (70.0%) were up-staged to the level of stage IV. Postoperational complications were not observed in any of these cases.

Conclusions: It was suggested that stage IIIc ovarian cancer with prominent diaphragmatic metastasis may advance to the level of stage IV from a clinical point of view even if carcinomatous pleural effusions are not detected pre-operationally. Therefore, it is thought that this operational method is useful in the management of progressive ovarian cancer.