<p>Electrosurgical apparatus (1) used for the thermocoagulation of a hepatic tumor tissue, comprising an electrosurgical current generator (10), operatively connected to one or more pairs of electrodes (31, 32) so as to attain a bipolar thermocoagulation mode; and means (40, 200) for assessing the impedance phase of the tissue comprised between the electrodes of said or each pair.</p>
