Treatment of spontaneous tumours by temporary local ligation. A comparative study in dogs.

Previous work in some human cases and in laboratory animals has indicated that temporary local ligation of spontaneous tumours has a selective destructive effect on these tumours, with only temporary inflammation resulting in normal tissues. In the experiments described in this paper, 49 spontaneous accessible tumours in dogs were treated by this method, with periods of ligation of from 4 to 11 hours. Success, as measured by selective necrosis of tumour tissue as compared with normal tissue, was achieved in 29 out of 41 benign tumours, including lipomas, angiomas, adenomas and mixed mammary tumours. Treatment failures were encountered in two cases each of papillomas and fibromas, six mixed mammary tumours and two testicular tumours. Total necrosis of tumour cells occurred in all eight malignant tumours encountered in this series.The outstanding feature was the specific destruction of tumour tissue by a bodily process without participation of any outside agent. Emphasis was placed on an adequate inflammatory response following temporary anoxia, although a precise definition of this inflammation could not be offered. Post-ligation bacterial multiplication, which may be expected to occur in necrotic tumour tissue, is considered to be a secondary effect rather than a possible primary cause of regression and disappearance of the tumour.If ligation treatment can be shown to be successful for a particular type of tumour, it may be possible to apply it to human patients for the treatment of areas not amenable to surgery.The results reported here warrant new experimental approaches to the study of neoplasms at the cellular level to define more precisely the anoxic and inflammatory processes involved in the selective lethal effect on tumour tissues; and the authors suggest that trials should be undertaken of combinations of chemotherapy or irradiation with ligation to reduce ligation time and extend the possible benefits.