title: Sarcomatoid differentiation as a prognostic factor for immunotherapy in metastatic renal cell carcinoma.
abstract: BACKGROUND
  The objective of the current study was to determine the significance of sarcomatoid differentiation as a prognostic factor for immunotherapy in metastatic renal cell carcinoma (RCC).
  
  
  METHODS
  Patients with metastatic RCC were included in this study and were categorized according to sarcomatoid differentiation.
  
  
  RESULTS
  Patients with sarcomatoid differentiation had more aggressive tumor characteristics than those without sarcomatoid differentiation. After immunotherapy, the median progression-free survival was 9.0 months (95% confidence interval [CI] 1.4-52.7) for patient without sarcomatoid differentiation and 3.2 months (95% CI 0.4-42.9) for patients with sarcomatoid differentiation, respectively (P=0.0001). The median overall survival was 22.2 months (95% CI 3.2-75.4) and 10.0 months (95% CI 0.7-60.1) in both groups. When comparing patients with sarcomatoid differentiation, there was no significant difference of overall survival in the immunotherapy group and the no immunotherapy group. Multivariate Cox proportional hazards model analysis showed that T stage (Hazard ratio [HR] 1.71; 95% CI 1.07-2.74; P=0.024), sarcomatoid differentiation (HR 2.18; 95% CI 1.30-3.66; P = 0.003), and the number of metastasis sites (HR 1.81; 95% CI 1.14-2.88; P=0.012) were independent predictors of progression-free survival. Sarcomatoid differentiation and the number of metastasis sites were independent prognostic predictors of overall survival. The estimated relative risks of sarcomatoid differentiation and the number of metastasis sites were 2.83 (95% CI 1.49-5.40; P=0.002) and 2.31 (95% CI 1.29-4.16; P=0.005), respectively.
  
  
  CONCLUSIONS
  Our findings suggest that sarcomatoid differentiation is an important prognostic factor for immunotherapy in metastatic RCC.
authors.affiliation: Department of Urology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Cheol
authors.initials: C
authors.lastname: Kwak
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Park
authors.forename: Chang Wook
authors.initials: CW
authors.lastname: Jeong
authors.forename: Hyeon
authors.initials: H
authors.lastname: Jeong
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Kyung Chul
authors.initials: KC
authors.lastname: Moon
authors.forename: Ja Hyeon
authors.initials: JH
authors.lastname: Ku
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002292:Carcinoma, Renal Cell / Q000401:mortality / Q000556:secondary* / Q000628:therapy; D002454:Cell Differentiation; D015331:Cohort Studies; D003131:Combined Modality Therapy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007167:Immunotherapy; D016898:Interferon-alpha / Q000627:therapeutic use; D007376:Interleukin-2 / Q000627:therapeutic use; D007680:Kidney Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009392:Nephrectomy; D011379:Prognosis; D012509:Sarcoma / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D015996:Survival Rate; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D016898:Interferon-alpha; D007376:Interleukin-2