Background:Hypoalbuminemia adversely affects the clinical outcomes of various cancers.The purpose of this study was to estimate the prognostic value of hypoalbuminemia 3-5 weeks after treatment in patients with metastatic renal cell carcinoma(mRCC) who received sorafenib or sunitinib as first-line treatment.Methods:In this single-center,retrospective study,we assessed the progression-free survival(PFS) and overall survival(OS) of 184 mRCC patients who received first-line sorafenib or sunitinib treatment.PFS and OS were compared between patients with post-treatment hypoalbuminemia(post-treatment albumin level <36.4 g/L) and those with normal post-treatment albumin level(albumin level≥36.4 g/L).The Memorial Sloan Kettering Cancer Center(MSKCC)risk model stratified mRCC patients into three risk categories.Prognostic values of all patient characteristics including MSKCC risk category were determined by using univariate and multivariate Cox regression models.Prognostic value was further determined using the Harrell concordance index and receiver operating characteristic curve analysis.Results:The median PFS and OS of the 184 patients were 11 months(95%confidence interval[CI]9-12 months)and 23 months(95%CI 19-33 months),respectively.Patients with post-treatment hypoalbuminemia had significantly shorter median PFS(6 months[95%CI 5-7 months]) and OS(11 months[95%CI 9-15 months]) than patients who had normal post-treatment albumin levels(PFS:12 months[95%CI 11-16 months],P < 0.001;OS:31 months[95%CI24-42 months],P < 0.001),respectively.Multivariate analysis showed that post-treatment hypoalbuminemia was an independent predictor of PFS(hazard ratio[HR],2.113;95%CI 1.390-3.212;P < 0.001) and OS(HR,2.388;95%CI 1.591-3.585;P < 0.001).Post-treatment hypoalbuminemia could also be combined with the MSKCC risk category for better prediction about OS.The model that included post-treatment hypoalbuminemia and MSKCC risk category improved the predictive accuracy for PFS and OS(c-index:0.68 and 0.73,respectively) compared with the basic MSKCC risk model(c-index:0.67 and 0.70,respectively).The prognostic values for PFS and OS of the integrated MSKCC risk model involving post-treatment hypoalbuminemia were significantly more accurate than the basic MSKCC risk model using likelihood ratio analysis(both P < 0.001).Conclusions:Post-treatment hypoalbuminemia can be considered an independent prognostic factor for patients with mRCC who undergo first-line treatment with tyrosine kinase inhibitors.Additionally,integrating post-treatment serum albumin level into the basic MSKCC risk model can improve the accuracy of this model in predicting patient overall survival and progression-free survival. Background: Hypoalbuminemia adversely affects the clinical of various cancers. The purpose of this study was to estimate the prognostic value of hypoalbuminemia for 3-5 weeks after treatment in patients with metastatic renal cell carcinoma (mRCC) who received sorafenib or sunitinib as first-line treatment.Methods: In this single-center, retrospective study, we assessed the progression-free survival (PFS) and overall survival (OS) of 184 mRCC patients who received first-line sorafenib or sunitinib treatment. PFS and OS were compared between patients with post-treatment hypoalbuminemia (post-treatment albumin level <36.4 g / L) and those with normal post-treatment albumin level (albumin level ≥36.4 g / L). The Memorial Sloan Kettering Cancer Center (MSKCC) risk model stratified mRCC patients into three risk categories. Precognostic values ​​of all patient characteristics including MSKCC risk category were determined by using univariate and multivariate Cox regression models. Prognostic value was further d Results were obtained using the Harrell Concordance index and receiver operating characteristic curve analysis. Results: The median PFS and OS of the 184 patients were 11 months (95% confidence interval [CI] 9-12 months) and 23 months (95% CI 19-33 months), respectively. Patients with post-treatment hypoalbuminemia had significantly shorter median PFS (6 months [95% CI 5-7 months]) and OS (11 months [95% CI 9-15 months]) than patients who had normal post -treatment albumin levels (PFS: 12 months [95% CI 11-16 months], P <0.001; OS: 31 months [95% CI 24-42 months], P <0.001 respectively). Multivariate analysis showed that post-treatment hypoalbuminemia was an independent predictor of PFS (hazard ratio [HR], 2.113; 95% CI 1.390-3.212; P <0.001) and OS (HR, 2.388; 95% CI 1.591-3.585; could also be combined with the MSKCC risk category for better prediction about OS. model that included post-treatment hypoalbuminemia and MSKCC risk category improved the predictive accuracy for PFS and OS (c-inde x:0.68 and 0.73, respectively) compared with the basic MSKCC risk model (c-index: 0.67 and 0.70, respectively). The prognostic values ​​for PFS and OS of the integrated MSKCC risk model involving post-treatment hypoalbuminemia were significantly more accurate than the basic MSKCC risk model using likelihood ratio analysis (both P <0.001) .Conclusions: Post-treatment hypoalbuminemia could be considered an independent prognostic factor for patients with mRCC who undergo first-line treatment with tyrosine kinase inhibitors. Additionally, integrating post-treatment serum albumin level into the basic MSKCC risk model can improve the accuracy of this model in predicting patient overall survival and progression-free survival.