Carcinoma gallbladder. A second opinion!

My father is diagnosed with carcinoma gallbladder and had undergone 6 cycle of chemotherapy. After the first 3 cycle of chemotherapy the size of the tumour decrease 50%. But after the next 3 cycle chemotherapy the size increases slightly. Impression after first 3 cycle of chemotherapy : There was significant interval reduction in the size and metabolic activity of primary lesion involving fundus and body of gallbladder Impression of second PET-CT Scan was: interval increase in size and metabolic activity of primary lesion There is no other evidence of metabolic active disease noted in the rest of the scanned segment of the body I have attached the first page of the PET CT Scan report after 1st 3 cycle and after next 3 cycle of the chemotherapy We want to know what to do next as a second opinion