Could The Elevated GGT Value Be Due To Chemotherapy?

Dear Dr. Oana, my friend was operated in December 2012 - gallbladder removed together with 6 nodes around with a diagnosis cancer in the very initial stage. The liver was proved not to be affected. Seven months later a PET scanner revealed a still good state of the liver but 2 small abdominal nodes (2-2.5 mm). This autumn since September he has started chemotherapy procedures which so far have indicated very satisfactory influence (nodes are diminished by 25%). Examinations and scanners show good treatment effect BUT - the GGT measured today (after hes 5th chemotherapy ) is too high - 1503. Please, tell me is it possible this extremely high GGT to be the result of the treatment. Does this happen with patients in similar state of medical treatment. Thank you very much, Dr Oana, for your answer.