Dear , thanks for the question. High blood pressure in case of your mother could be due to age related too, as high blood pressure is quite common in people beyond 50 years of age (I presume your mother is beyond 50). However chemotherapy and radiotherapy can also cause high blood pressure due to damage to kidneys as chemotherapy is highly toxic to kidneys. Your mother need to visit physician immediately as this level of blood pressure could be dangerous. She needs to under go detailed investigations like kidney function, thyroid, lipid profile, blood profile to detect the cause of high blood pressure. Meanwhile ask her to start physical activities, fat free and low salt diet. I wish your mother a healthy life ahead.