Concepts The current concept of maintenance therapy is divided into two types: continuation maintenance therapy and maintenance therapy with a change of drug. Continued maintenance therapy refers to treatment with at least one drug that was used in the first-line regimen after 4-6 cycles of first-line therapy if no disease progression has occurred. Maintenance therapy with a different drug not included in the first-line regimen is initiated after 4-6 cycles of first-line therapy if no disease progression occurs. The ideal maintenance drug should be effective as a single agent, have low side effects, and be easy to use. Chemotherapeutic agents for maintenance therapy A randomized, double-blind, multicenter phase III clinical study evaluating pemetrexed maintenance therapy (JMEN) was presented by Ciuleanu et al. at the ASCO Annual Meeting in 2008. In 2009, Belani et al. reported the final results of the study, which showed that the median survival (OS) of the pemetrexed maintenance group was better than that of the placebo group (13.4 months versus 10.6 months, with a 21% reduction in the risk of death, including a more pronounced survival benefit in patients with non-squamous cancer (15.5 months versus 10.3 months) and a 30% reduction in the risk of death, thus concluding that first-line chemotherapy for advanced non-small cell lung cancer The use of maintenance therapy with pemetrexed after benefit is considered a new treatment paradigm, especially for patients with non-squamous cancer. Because of the scientific design of this study and the prolonged survival achieved, pemetrexed was approved in the United States and the European Union for the maintenance treatment of non-squamous cancer patients with progression-free disease after platinum-based therapy, and was recommended in the NCCN guidelines, finally ushering in a ray of hope for maintenance therapy. Targeted therapy for maintenance treatment Targeted drugs have attracted more attention in the research of maintenance treatment because of the advantages of small side effects and convenience of administration. In 2009, Italian scholars Cappuzzo et al) reported the preliminary results of the multicenter phase III study (SATURN) of maintenance therapy with erlotinib at the ASCO annual meeting, and the trial results were subsequently supplemented at the World Conference on Lung Cancer and the European Society of Medical Oncology (ESMO) congress that year. The results showed that PFS was significantly prolonged in the erlotinib group compared to the placebo group (12.3 weeks versus 11.0 weeks); it was also prolonged in the OS maintenance group, 12.0 months versus 11.0 months, especially in the maintenance group of patients with non-squamous cancer, with 13.7 months in the maintenance group (272 patients) and 10.5 months in the placebo group (257 patients). Subgroup analysis showed that patients of different gender, pathological type, ethnicity, smoking status, and EGFR wild type or mutation could benefit from erlotinib maintenance therapy. In addition maintenance therapy delayed the onset of pain and the use of analgesics in patients. The safety profile of erlotinib maintenance therapy is good, and the positive results of the SATURN study have provided further insight into maintenance therapy. In light of the SATURN study, the 2010 NCCN guidelines recommended that patients with advanced NSCLC who have not progressed after first-line chemotherapy can be treated with maintenance therapy with erlotinib replacement. A phase III clinical study of gefitinib maintenance therapy (INFORM) was also reported by our scholar Tension at the ASCO annual meeting. This study involved 27 oncology centers in China and showed that PFS was significantly longer in the gefitinib group than in the control group (4.8 months versus 2.6 months), with a 58% reduction in the risk of disease progression in the maintenance group and an unpublished OS. Patients were well tolerated. EGFR testing was performed in 79 of the enrolled patients, with a mutation rate of 38%; the PFS in the gefitinib and control groups among patients with mutations was 16.6 months and 2.7 months, respectively, with a risk ratio of 0.16, so the benefit was greater in patients with EGFR mutations, but further validation is needed because of the small sample size.