My Mom Is Having Colon Cancer Stage 3. She Is

My mom is having colon cancer stage 3. She is 45 years of age. She had an operation of left hemicolectomy in july, 2015. From Aug, 2015, her chemotherapy got started. One month back she had cea level 7. After one month the cea test result is 11. She has already taken 6 chemo. Suggest me whether the chemo is working or not? Or any remedy? Doe's it signify the progression of colon cancer again? If you want to know any test details just ask me. But, please provide a way out to to minimize this level.