Histopathological changes associated with high intensity focused ultrasound (HIFU) treatment for localised adenocarcinoma of the prostate

Aims-Investigation of the histopathological changes in prostatectomy specim ens of patients with prostate cancer after high intensity focused ultrasoun d (HIFU) and identification of immunohistochemical markers for tissue damag e after HIFU treatment. Methods-Nine patients diagnosed with adenocarcinoma of the prostate underwe nt unilateral HIFU treatment seven to 12 days before radical prostatectomy. The prostatectomy specimens were analysed histologically. Immunohistochemi cal staining and electron microscopy were performed to characterise more su btle phenotypic changes. Results-All prostatectomy specimens revealed well circumscribed HIFU lesion s at the dorsal side of the prostate lobe treated. Most epithelial glands i n the centre of the HIFU lesions revealed signs of necrosis. Glands without apparently necrotic features were also situated in the HIFU lesions, raisi ng the question of whether lethal destruction had occurred. This epithelium reacted with antibodies to pan-cytokeratin, prostate specific antigen (PSA ), and Ki67, but did nor express cytokeratin 8, which is indicative of seve re cellular damage. Ultrastructural examination revealed disintegration of cellular membranes and cytoplasmic organelles consistent with cell necrosis . HIFU treatment was incomplete at the ventral, lateral, and dorsal sides o f the prostate lobe treated. Conclusions-HIFU treatment induces a spectrum of morphological changes rang ing from apparent light microscopic necrosis to more subtle ultrastructural cell damage. All HIFU lesions are marked by loss of cytokeratin 8. HIFU do es not affect the whole area treated, leaving vital tissue at the ventral, lateral, and dorsal sides of the prostate.