[Ultrastructural findings in carcinoma of the prostate after combined endocrine and radiation treatment].

Carcinomas of the prostate treated by orchiectomy, 60Co-radiation, and hormonal drugs a relatively short time prior to the time of biopsy were studied with the electron microscope. The following degenerative changes of tumor cells and fibromuscular stroma were found: The nuclei of the tumor cells were intensely heterochromatic, irregularly shaped, and the perinuclear rim dilated; large atypical sizes, multiple segmentations and "nuclear invaginations" were observed. The tumor cell cytoplasm showed vacuolar degeneration, and the limiting membranes of the tumor cells were extensively destroyed. Remarkable changes were also found in the fibromuscular stroma: There was a proliferation of collagenous fibers as well as degenerative transformations ending in hyalinization. The smooth muscle cells were dissociated and fragmented, sometimes showing vacuolar degeneration of the cytoplasm. The endothelium of the blood vessels was swollen, and the vessel walls were thickened. In spite of these radiation-induced lesions it remains undecided as to what degree the other therapeutic measures take part in the total therapeutic effects as seen in the ultrastructural findings. However, these regressive changes are much more pronounced than those seen after orchiectomy alone and partly resemble the findings which are characteristic of radiation induced structural lesions. The morphological changes are not uniform throughout the tumor. It is not unusual to find intact tumor cells next to totally degenerated cells. They represent poorly differentiated tumor cells. It is discussed whether these "embryonic" tumor cell types are and remain resistant to treatment and if a tumor recurrance may originate in them later on.