title: Feasibility of using CT volume as a predictor of specimen weight in a subgroup of patients with low risk Wilms tumors registered on COG Study AREN03B2: implications for central venous catheter placement.
abstract: OBJECTIVE
  Patients with stage I Wilms tumor, age ≤ 2 years, tumor ≤ 550 g may not require therapy beyond nephrectomy. This study's aims were to determine: (1) if a linear relationship exists between tumor weight and computed tomography (CT) estimated volume; (2) describe the accuracy of a slope-intercept equation in estimating weight; and (3) determine the potential impact of weight estimation on port placement decisions.
  
  
  METHODS
  Tumor weight and port placement information were abstracted from 105 patients, age ≤ 2 years, with tumors ± 550 g, enrolled in COG AREN03B2. One radiologist estimated tumor size from CT scan. Prolate ellipse volume (PEV) was calculated, linear regression performed, slope-intercept equation calculated, equation estimated weight determined, and potential impact of the on port placement evaluated.
  
  
  RESULTS
  A strong relationship exists between PEV and weight (R(2) = 0.87). The slope-intercept equation for weight was: weight = 1.04(PEV) + 58.75. Overall median relative error for the equation was 0.9%, and -3% in tumors weighing 350-750 g. Fifty-five ports were placed, 29 in patients with tumor weight ≤ 550 g, and six not placed in patients with tumor weight > 550 g.
  
  
  CONCLUSIONS
  The relationship between PEV and weight produced a reliable weight prediction equation. Preoperative consideration of specimen weight may diminish the number of ports placed in this population.
authors.affiliation: Connecticut Children's Medical Center, University of Connecticut Medical School, 282 Washington Street, Hartford, CT 06106, USA. Electronic address: fferrer@connecticutchildrens.org.
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Ferrer
authors.affiliation: Connecticut Children's Medical Center, University of Connecticut Medical School, 282 Washington Street, Hartford, CT 06106, USA. Electronic address: kherbst@connecticutchildrens.org.
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Herbst
authors.affiliation: IWK Health Center, Halifax, NS, Canada. Electronic address: Conrad.Fernandez@iwk.nshealth.ca.
authors.forename: Conrad V
authors.initials: CV
authors.lastname: Fernandez
authors.affiliation: Washington University School of Medicine, St. Louis, MO, USA. Electronic address: khannag@mir.wustl.edu.
authors.forename: Geetika
authors.initials: G
authors.lastname: Khanna
authors.affiliation: Children's National Medical Center, Washington, DC, USA. Electronic address: JDome@childrensnational.org.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Dome
authors.affiliation: Children's Oncology Group Statistics & Data Center, University of Florida, Gainesville, FL, USA. Electronic address: anaranjo@cog.ufl.edu.
authors.forename: Arlene
authors.initials: A
authors.lastname: Naranjo
authors.affiliation: Children's Hospital of Boston, Boston, MA, USA. Electronic address: Elizabeth_Mullen@dfci.harvard.edu.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Mullen
authors.affiliation: Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA. Electronic address: james.geller@cchmc.org.
authors.forename: James I
authors.initials: JI
authors.lastname: Geller
authors.affiliation: Children's Hospital at Erlanger, Chattanooga, TN, USA. Electronic address: egratiasmd@comcast.net.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Gratias
authors.affiliation: Children's Hospital of Boston, Boston, MA, USA. Electronic address: robert.shamberger@childrens.harvard.edu.
authors.forename: Robert
authors.initials: R
authors.lastname: Shamberger
authors.affiliation: Mayo Clinic College of Medicine, Phoenix, AZ, USA. Electronic address: michael.ritchey@gmail.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Ritchey
authors.affiliation: University of Michigan Medical School, Ann Arbor, MI, USA. Electronic address: pehrlich@med.umich.edu.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Ehrlich
mesh_terms: D002405:Catheterization, Central Venous; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D008297:Male; D009367:Neoplasm Staging; D009392:Nephrectomy; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D009396:Wilms Tumor / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery
keywords: Central venous catheter; Computed tomography; Nephrectomy; Nephroblastoma; Wilms tumor