Heat fixation of cancer cells ablated with high-intensity-focused ultrasound in patients with breast cancer

BACKGROUND: High-intensity-focused ultrasound (HIFU) is a noninvasive thermal ablation technique. This study reports the use of histological techniques for the pathological assessment of HIFU effects in patients with breast cancer. METHODS: Twenty-three patients with biopsy-proven breast cancer underwent HIFU treatment for primary breast lesion. Mastectomy was performed on all patients after HIFU. By using histological examinations, the surgical specimens were assessed to explore HIFU effects on breast cancer. RESULTS: Coagulation necrosis of targeted tumors was confirmed by microscopy in 23 patients. Tumor cells presented typical characteristics of coagulation necrosis in the peripheral region of the ablated tumor in all patients. However, in 11 of 23 patients, hematoxylin and eosin staining showed normal cellular structure in the central ablated tumor. By using electronic microscopy and nicotinamide adenine dinucleotide-diaphorase stain, those who had normal-appearing cancer cells were not viable. CONCLUSIONS: HIFU can cause the heat fixation of ablated tumor through thermal effect.