Abstract: Clinical Observation of Dose-Dense Chemotherapy with THP in the Postoperative Treatment ofHigh Risk Breast CancerHongbo REN1, Zhonghui BAO1, Jifan YANG1, Biyou HUANG1, Shaolin LI2Correspondence to: Shaolin LI, E-mail: rhb2006@sina.com1Department of Oncology, The Second People’ s Hospital, Chongqing 400054, China2Department of Oncology, Chongqing University of Medical Sciences, Chongqing 400016, ChinaThis work was supported by the National Natural Science Foundation of China (No.30424005)Abstract Objective: To observe the clinical effect of dose-dense chemotherapy with THP-containing agents in the postopera-tive treatment for high risk breast cancer. Methods: During a period from January 2004 to December 2005, 81 patients with high riskbreast cancer were randomly allocated into two groups: the Dose-dense Group (G1) and the Conventional Chemotherapy Group (G2).The dose of the chemotherapeutic agents was THP60mg/m2d1 and PTX175mg/m2d2. The administration was repeated every 14 daysin the G1 group and every 21 days in the G2 group, with a total treatment of 4 cycles. Results: There were 41 patients in the G1 groupand 40 patients in the G2 group. All 81 patients completed chemotherapy as planned. All patients were followed-up for more than 5years, with a follow-up rate of 95.06%. The 3-year overall survival rate was 92.68% and 75.0% ( χ2= 4.70, P < 0.05 ) in G1 and G2, re-spectively. The 3-year relapse-free rate was 87.80% and 67.50% in the two groups ( χ2= 4.83, P < 0.05 ), with significant differences be-tween the two groups. The 5-year overall survival rate was 60.97% and 35.00% ( χ2= 5.47, P < 0.05 ) in G1 and G2, and the 5-year tu-mor-free survival was 53.65% and 27.5%% ( χ2= 5.74, P < 0.05 ) in G1 and G2, respectively, with significant differences between thetwo groups. The major toxicities included neutropenia, nausea, vomiting, hepatic lesions and alopecia. The incidence of gradeⅠ-Ⅱandgrade Ⅲ-Ⅳ neutropenia were 70.73% and 21.94% in G1, respectively, and the incidence of grade Ⅰ-Ⅱand grade III-IV thrombopeniawere 31.71% and 0 in G1, respectively. The incidence of gradeⅠ-Ⅱand grade Ⅲ-Ⅳ neutropenia were 54.20% and 25.00% in G2, re-spectively, and the incidence of gradeⅠ-Ⅱand grade III-IV thrombopenia were 12.50% and 0 in G2, respectively. The median DFS andOS were not obtained. Agranulocytic fever was not observed in any patients. Conclusion: Postoperative dose-dense chemotherapy forhigh risk breast cancer can effectively improve the 3- and 5-year survival rates and the adverse side effects are tolerable.Keywords Breast cancer; Dose-dense chemotherapy; Adjuvant chemotherapy; THP