Abstract
To study the role of the diaphragm as a barrier to hinder transdiaphragmatic spread of cancer cells, the incidence of carcinomatous pleuritis and peritonitis was retrospectively evaluated in 6, 145 cases with various carcinomas admitted to the Juntendo University Hospital from 1979 to 1988. The patients were divided into two groups according to the primary sites of the carcinomas, e.g. SD group (1, 199 cases) included the patients who had the primary site in supradiaphragmatic organs, and ID group (4, 969 cases), in infradiaphragmatic organs. The incidence of carcinomatous pleuritis alone, carcinomatous peritonitis alone, and both the pleuritis and peritonitis was 12.3%, 0.3% and 1.1% in the SD group, and 0.7%, 9.9% and 2.0% in the ID group, respectively. The incidence of carcinomatous pleuroperitonitis in the ID group was significantly higher than that in the SD group (p<0.01). Of those complicated with carcinomatous pleuritis and/or carcinomatous peritonitis, 190 cases were available for analysis of autopsy findings. Transdiaphragmatic lymphogenous metastasis were more frequent in patients with carcinomatous pleuroperitonitis than those with pleuritis alone or peritonitis alone (73.3%vs 38.7% in the SD group (p<0.05), and 78.3% vs 37.3%(p<0.01) in the ID group, respectively). These results indicate that the diaphragm usually protects against direct invasion of cancer cells between the pleural and peritoneal spaces. However, this barrier was sometimes disrupted by the spread through the transdiaphragmatic lymphogenous pathway. In addition, cancer spread from infradiaphragmatic organs to the pleural space occurs more frequently than that from supradiaphragmatic organs to the peritoneal space.
