Hiroki Ishihara1, Toshio Takagi1, Tsunenori Kondo2, Kana Iwamoto2, Hidekazu Tachibana2, Kazuhiko Yoshida1, Kenji Omae1,3,4, Junpei Iizuka1, Hirohito Kobayashi1, Kazunari Tanabe1. 1. Department of Urology, Kidney Center, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo. 2. Department of Urology, Tokyo Women's Medical University Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo. 3. Department of Healthcare Epidemiology, Kyoto University Graduate School of Medicine/ School of Public Health, Yoshida Konoe-cho, Sakyo-ku, Kyoto. 4. Center for Innovative Research for Communities and Clinical Excellence, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, Fukushima, Japan.
Abstract
BACKGROUND: Relative dose intensity is an indicator of therapeutic efficacy in sunitinib treatment for metastatic renal cell carcinoma. However, the number of studies investigating the influence of decreased relative dose intensity during the early phase on oncological outcome is limited. METHODS: A total of 105 patients who received first-line sunitinib treatment for metastatic renal cell carcinoma were evaluated. We assessed the relative dose intensity during the initial first cycle (1c-RDI). We found that an optimal threshold of 1c-RDI was associated with progression-free survival and overall survival after the initiation of sunitinib treatment. Additionally, predictive factors for decreased 1c-RDI were analyzed. RESULTS: The 1c-RDI threshold was determined at 60%. Patients with low 1c-RDI (<60%, n = 26, [24.8%]) had significantly shorter median progression-free survival (5.79 vs. 14.0 months, P = 0.0014) and overall survival (13.3 vs. 34.4 months, P = 0.0005) durations than those with high 1c-RDI (≥60%, n = 79 [75.2%]). Multivariate analysis showed that the development of dose-limiting toxicity was an independent factor for low 1c-RDI (odds ratio: 3.09, 95% confidence interval: 1.14-8.37, P = 0.0266) after adjustment with an initial dose of sunitinib. CONCLUSIONS: More than 60% of 1c-RDI is needed for effective sunitinib treatment. Patient tolerability should be carefully monitored to avoid the development of dose-limiting toxicity during the early phase of treatment.
BACKGROUND: Relative dose intensity is an indicator of therapeutic efficacy in sunitinib treatment for metastatic renal cell carcinoma. However, the number of studies investigating the influence of decreased relative dose intensity during the early phase on oncological outcome is limited. METHODS: A total of 105 patients who received first-line sunitinib treatment for metastatic renal cell carcinoma were evaluated. We assessed the relative dose intensity during the initial first cycle (1c-RDI). We found that an optimal threshold of 1c-RDI was associated with progression-free survival and overall survival after the initiation of sunitinib treatment. Additionally, predictive factors for decreased 1c-RDI were analyzed. RESULTS: The 1c-RDI threshold was determined at 60%. Patients with low 1c-RDI (<60%, n = 26, [24.8%]) had significantly shorter median progression-free survival (5.79 vs. 14.0 months, P = 0.0014) and overall survival (13.3 vs. 34.4 months, P = 0.0005) durations than those with high 1c-RDI (≥60%, n = 79 [75.2%]). Multivariate analysis showed that the development of dose-limiting toxicity was an independent factor for low 1c-RDI (odds ratio: 3.09, 95% confidence interval: 1.14-8.37, P = 0.0266) after adjustment with an initial dose of sunitinib. CONCLUSIONS: More than 60% of 1c-RDI is needed for effective sunitinib treatment. Patient tolerability should be carefully monitored to avoid the development of dose-limiting toxicity during the early phase of treatment.