New aspects concerning tumor cell inactivation and histopathologic assessment after radiofrequency therapy. Observations in a treatment case and in vitro proof of a new hypothesis

In a study,a radiofrequency (RF) treatment was performed on a patient with a small breast cancer after vacuum biopsy. As usual in cases with a maligna nt diagnosis, surgical excision and axillary dissection followed. Histopathology revealed some residual tumor in the margin of the cavity. It could not be distinguished from vital tumor on the hematotoxylin eosin (HE ) stain. Based on the correlation of MRI and histopathology after subsequen t surgical excision,we did, however, presume that the residual was containe d within the zone of inactivation. Thus the hypothesis arose that, if too h igh temperatures can be avoided, it might be possible to inactivate tumor c ells without significantly impairing histopathologic assessment. This hypothesis was supported by the following in vitro experiment performe d on a fresh specimen: An RF treatment was performed using temperatures up to 70 degreesC only. Half of the specimen underwent HE-staining, the other half vitality testing. The results indicate that if a given temperature ran ge is strictly observed it appears possible to inactivate tissue before tis sue sampling, since histopathologic diagnosis will not be impaired. Further technologic improvements may eventually allow to develop a pre-treatment m ethod which might permit to avoid potential hematogenous tumor spread durin g subsequent biopsy.