title: Is anatomic complexity associated with renal tumor growth kinetics under active surveillance?
abstract: BACKGROUND
  Linear growth rate (LGR) is the most commonly employed trigger for definitive intervention in patients with renal masses managed with an initial period of active surveillance (AS). Using our institutional cohort, we explored the association between tumor anatomic complexity at presentation and LGR in patients managed with AS.
  
  
  METHODS
  Enhancing renal masses managed expectantly for at least 6 months were included for analysis. The association between Nephrometry Score and LGR was assessed using generalized estimating equations, adjusting for the age, Charlson score, race, sex, and initial tumor size.
  
  
  RESULTS
  Overall, 346 patients (401 masses) met the inclusion criteria (18% ≥ cT1b), with a median follow-up of 37 months (range: 6-169). Of these, 44% patients showed progression to definitive intervention with a median duration of 27 months (range: 6-130). On comparing patients managed expectantly to those requiring intervention, no difference was seen in median tumor size at presentation (2.2 vs. 2.2 cm), whereas significant differences in median age (74 vs. 65 y, P < 0.001), Charlson comorbidity score (3 vs. 2, P<0.001), and average LGR (0.23 vs. 0.49 cm/y, P < 0.001) were observed between groups. Following adjustment, for each 1-point increase in Nephrometry Score sum, the average tumor LGR increased by 0.037 cm/y (P = 0.002). Of the entire cohort, 6 patients (1.7%) showed progression to metastatic disease.
  
  
  CONCLUSIONS
  The demonstrated association between anatomic tumor complexity at presentation and renal masses of LGR of clinical stage 1 under AS may afford a clinically useful cue to tailor individual patient radiographic surveillance schedules and warrants further evaluation.
authors.affiliation: Department of Urology & Oncological Science, Icahn School of Medicine at Mount Sinai, New York, NY.
authors.forename: Reza
authors.initials: R
authors.lastname: Mehrazin
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA.
authors.forename: Marc C
authors.initials: MC
authors.lastname: Smaldone
authors.affiliation: Biostatistics & Bioinformatics Facility, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA.
authors.forename: Brian
authors.initials: B
authors.lastname: Egleston
authors.affiliation: Department of Surgery, MD Anderson Cancer Center at Cooper, Rowan, University School of Medicine, Camden, NJ.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Tomaszewski
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Concodora
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA.
authors.forename: Timothy K
authors.initials: TK
authors.lastname: Ito
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA.
authors.forename: Philip H
authors.initials: PH
authors.lastname: Abbosh
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA.
authors.forename: David Y T
authors.initials: DY
authors.lastname: Chen
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kutikov
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA. Electronic address: Robert.Uzzo@fccc.edu.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Uzzo
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D057832:Watchful Waiting
keywords: Active surveillance; Growth kinetics; Nephrometry Score; Renal cell carcinoma; Renal tumor; Tumor complexity