Abstract: Colorectal cancer is one of the common malignant tumors,and its morbidity and mortality are in the third and fourth places,respectively.About 60% of patients are in an advanced stage at the diagnosis,and their 5-year survival rate is around 13%.In the past 20 years,since the standardized application of advanced first-line chemotherapy and targeted drugs for metastatic colorectal cancer(mCRC),mCRC treatment has made a major breakthrough.The use of oxaliplatin,capecitabine,bevacizumab,cetuximab and other drugs have doubled the median survival and increased the 5-year survival rate by 20%.The usual mode of first-line treatment of mCRC in the late stage is continuous medication until the disease progress or the intolerable toxicity occurs.However,because of the accumulation of toxicity of chemotherapy drugs,only one-third of patients can continue to receive treatment until the disease progresses.After completing established initial treatment cycle and achieving CR/PR/SD,the patients continue to use low-dose,low-toxic drugs for maintenance treatment,which can delay the progression and metastasis of the tumor,and reduce the side effects of drug.At present,maintenance therapy has become the main treatment mode after advanced first-line chemotherapy for mCRC.However,the optimal maintenance regimen for mCRC remains inconclusive,and existing maintenance regimens still do not find a balance between optimal outcome and maximum quality of life.This article will review the clinical studies of mCRC's existing maintenance treatment regimens,summarize the current status of mCRC maintenance therapy,and discuss individualized treatment strategies.

Key words: Metastatic colorectal cancer, Maintenance treatment, Capecitabine, Bevacizumab