The association between nephroblastoma-specific outcomes and high versus low volume treatment centers.
BACKGROUND
Though the volume-outcome relationship has been well-established in adults, low mortality rates and small sample sizes have precluded definitive demonstration in children. This study compares treatment-specific factors for children with nephroblastoma at high (HVC) versus low volume centers (LVC).


METHODS
We performed a retrospective cohort study comparing patients ≤18years with unilateral nephroblastoma treated at HVCs and LVCs using the National Cancer Data Base (1998-2012). Definitions of HVCs included performing above the median, the upper two quartiles, and the highest decile of nephroblastoma resections. Outcomes included nodal sampling, margin status, time to chemotherapy and radiation, and survival. Statistical analyses included χ2, t-tests, generalized linear, and Cox regression models (p<0.05).


RESULTS
Of 2911 patients from 210 centers, 1443 (49.6%) were treated at HVCs. There was no difference in frequency of preoperative biopsy or days to radiation (p>0.05). High volume centers were more likely to perform nodal sampling (RR 1.04, 95%CI 1.01-1.08) and had fewer days to chemotherapy (RR 0.80, 95%CI 0.69-0.93). Five-year survival was similar (HVC: 0.93, 95%CI 0.92-0.94; LVC: 0.93, 95%CI 0.91-0.94).


CONCLUSIONS
HVCs were more likely to perform nodal sampling and had fewer days to chemotherapy. There was no difference in days to radiation or survival between centers.


METHODS
Level II (retrospective prognosis study).
University of Washington, Department of Surgery; Seattle Children's Hospital, Department of Thoracic and General Surgery. Electronic address: morgan.richards@gmail.com.
Morgan K
MK
Richards
Seattle Children's Hospital, Department of Thoracic and General Surgery.
Adam B
AB
Goldin
Emory University School of Medicine.
Alexandra
A
Savinkina
Methodist Children's Hospital of South Texas.
John
J
Doski
John Wayne Cancer Institute.
Melanie
M
Goldfarb
Baylor College of Medicine.
Jed
J
Nuchtern
Maine Children's Cancer Program.
Monica
M
Langer
University of Alabama, Birmingham.
Elizabeth A
EA
Beierle
Baylor College of Medicine.
Sanjeev
S
Vasudevan
Seattle Children's Hospital, Department of Thoracic and General Surgery.
Kenneth W
KW
Gow
Emory University School of Medicine.
Mehul V
MV
Raval
D000293:Adolescent; D059186:Chemoradiotherapy, Adjuvant / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D005260:Female; D054625:Healthcare Disparities / Q000706:statistics & numerical data*; D061847:Hospitals, High-Volume; D061846:Hospitals, Low-Volume; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007680:Kidney Neoplasms / Q000401:mortality / Q000628:therapy*; D008197:Lymph Node Excision / Q000706:statistics & numerical data; D008297:Male; D009392:Nephrectomy / Q000706:statistics & numerical data; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016896:Treatment Outcome; D014481:United States; D009396:Wilms Tumor / Q000401:mortality / Q000628:therapy*
National Cancer Data Base; Nephroblastoma; Volume-outcome; Wilms' tumor