Clinical Investigation Of TS-1 Monotherapy As Thirdline Option For Metastatic Breast Cancer

Objective To investigate the efficacy and safety of TS-1 as the third line option on metastatic breast cancer patients.Methods 49 female metastatic breast cancer patients were enrolled with the history of two kinds of cytotoxic chemotherapies(the hisitory of monotheray including hormonal treatment, targeted therapy and oral fluorouracil is excluded). The patients should stay in at least 4 week-interval following the latest end of chemotherapy and targeted therapy or radiotherapy and more than 2-week interval post the end of hormonal therapy with good KPS status(≥70). The patients have no clinical manifestation in case of brain metastasis. Patients were treated with TS-1 capsule: 40mg/m2 per time, twice a day, oral administration within 30 minutes after meals for 28 days, the following rest for 14 days. Each cycle contains 6 weeks and 12 weeks following CT or MRI evaluation according to RECIST1.1 and adverse events record referring to CTCAE4.0.Using SPSS 19.0 statistical software for data analysis.Results One patient ceased the first cycle of treatment due to severe facial rash. 48 metastatic breast cancer patients were evaluated with complete response 0%(0/48), partial response 20.83%(10/48), stable disease 50%(24/48), progressive disease 29.17%(14/48),objective reaction rate 20.83%(10/48), disease control rate 70.83%(34/48), median progression-free survival 5.9 months. With the retrospective data analysis using capecitabine as 3rd line treatment of patients with metastatic breast cancer,35 cases with PR 14.29%(5/35), SD 45.71%(16/35), PD 40%(14/35), ORR 14.29%, DCR 60%. Comparison between the two drugs had no significant difference. The dose dependent toxicities include myelosuppression and diarrhea. Aminotransferase increasement, pigmentation, nausea, stomatitis and rash were also observed.Conclusion TS-1 compared with capecitabine as the third line option on metastatic breast cancer patients, TS-1 can improve the objective reaction rates and disease control rates basically the same with capecitabine, alleviate the adverse reactions, and be convenient for medication, which is worthy of further clinic exploration.