title: Percentage of sarcomatoid component as a prognostic indicator for survival in renal cell carcinoma with sarcomatoid dedifferentiation.
abstract: OBJECTIVE
  Renal cell carcinoma with sarcomatoid dedifferentiation (sRCC) is associated with higher stage of presentation and worse survival. The objective of this study was to examine the clinicopathologic characteristics associated with overall survival (OS), specifically examining the percentage of sarcomatoid component (PSC).
  
  
  METHODS
  We reviewed clinicopathologic data for all nephrectomized patients with confirmed sRCC. Histologic slides were rereviewed by dedicated genitourinary pathologists to ascertain PSC. Patient characteristics were tabulated overall and by disease stage. Cutpoints in the PSC providing a meaningful difference in OS were identified by recursive partitioning analysis (RPA). Factors selected included age group, gender, race, clinical stage, tumor histology, presurgical systemic therapy, lymphovascular invasion, and tumor size. The Kaplan-Meier method and log-rank test were used to assess differences in OS.
  
  
  RESULTS
  Among 186 patients with sRCC, 64 (34%) had localized, and 122 (66%) had metastatic disease at presentation. Patients had primarily clear cell histology (73%). Median follow-up was 12.1 months (range: 0.1-242.2mo). Median OS was 12.6 months (95% CI: 10.7-14.9mo). Univariate RPA identified a PSC cutpoint of 10% as prognostically significant. Patients with PSC>10% were at higher risk of death when compared with patients with PSC≤10% (45% vs. 61% 1-y OS; P = 0.04). Multivariate RPA revealed that tumor size, presence of metastatic disease, and PSC were significantly associated with OS. Among 4 identified groups, patients with localized disease and tumor size≤10cm were most likely to be alive at 1 year (89%), and patients with metastatic disease and PSC>40% were least likely to be alive at 1 year (28%; P<0.001).
  
  
  CONCLUSIONS
  PSC appears to be a prognostic factor in patients with sRCC, with larger percentage of involvement portending a worse survival, especially in patients with metastatic disease.
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Mehrad
authors.initials: M
authors.lastname: Adibi
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Arun Z
authors.initials: AZ
authors.lastname: Thomas
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Leonardo D
authors.initials: LD
authors.lastname: Borregales
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Megan M
authors.initials: MM
authors.lastname: Merrill
authors.affiliation: Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Slack
authors.affiliation: Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Hsiang-Chun
authors.initials: HC
authors.lastname: Chen
authors.affiliation: Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Kanishka
authors.initials: K
authors.lastname: Sircar
authors.affiliation: Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Paari
authors.initials: P
authors.lastname: Murugan
authors.affiliation: Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Pheroze
authors.initials: P
authors.lastname: Tamboli
authors.affiliation: Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Eric
authors.initials: E
authors.lastname: Jonasch
authors.affiliation: Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Nizar M
authors.initials: NM
authors.lastname: Tannir
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Surena F
authors.initials: SF
authors.lastname: Matin
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Wood
authors.affiliation: Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX. Electronic address: JAKaram@mdanderson.org.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Karam
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000401:mortality / Q000473:pathology*; D054337:Cell Dedifferentiation; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012509:Sarcoma / Q000473:pathology
keywords: Nephrectomy; Percentage; Recursive partitioning analysis; Renal cell carcinoma; Sarcomatoid