Treatment after oncological surgery.

My wife aged 62 was suffering from jaundice. We came to know on 25.08.18. After so many tests like ultrasound, ct scan, pet ct scan, mri, Doctors told stone in gall bladder, bile duct blockage and assumed cancer. On 20.09.18 the open surgery was performed and gall bladder was 08 removed. Doctors told that they removed all the cells. Now they are asking for chemotherapy minimum 4 cycles, which costs in total around 2 lacs including hospitalization charges. Whether chemotherapy is necessary ? Biopsy is done on removed part then how can be assumed that cancer cells are still there, while Doctor told that he removed all cells. Whether they can ask for radiotherapy alsi after chemothrapy? Is there any treatment with you in minimum cost in homeopathy or ayurveda.