title: Treatment of renal angiomyolipoma: pooled analysis of individual patient data.
abstract: BACKGROUND
  This study was performed to evaluate the impact of baseline characteristics and treatment methods on the outcome of sporadic renal angiomyolipoma (AML).
  
  
  METHODS
  This was a pooled analysis of individual data of 441 patients with AML retrieved from 58 studies and 3 institutional series.
  
  
  RESULTS
  Ninety-three patients underwent nephrectomy, 163 partial nephrectomy/enucleation, 128 embolisation, 19 cryoablation, 6 radiofrequency ablation, and 32 conservative treatment. Their mean follow-up period was 44.5 months. Patients who experienced major bleeding at presentation had significantly larger tumours than did those without bleeding (mean diameter, 10.1 vs. 5.9 cm, respectively; p < 0.0001). A total of 9.4 % and 26.4 % of bleeding tumours had a diameter of <4 and <6 cm, respectively. A tumour diameter of ≥8.0 cm (hazard ratio, 2.07; 95 % confidence interval, 1.20-4.77) and the treatment method (p = 0.001) were independent predictors of re-intervention. The risk of re-intervention was significantly higher after embolisation, particularly for large tumours (5-year rate of freedom from re-intervention: diameter of ≥8.0 cm, 49.2 %; diameter of <8.0 cm, 74.8 %; p = 0.018). Conservatively treated AMLs had a mean baseline diameter of 3.2 ± 2.7 cm; after 41 months, their mean diameter was 3.7 ± 3.1 cm (p = 0.109).
  
  
  CONCLUSIONS
  The prevalence of major bleeding is high in sporadic AMLs with a diameter of >6 cm. These results suggest that conservative treatment can be considered in AMLs of <6 cm in diameter. Among current treatment methods, embolisation was associated with a significantly higher risk of re-intervention. Further studies are needed to define risk factors for bleeding and assess the relative benefits of different treatment modalities.
authors.affiliation: Department of Surgery and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 21, 90029 OYS, Oulu, Finland. teele.kuusk@gmail.com.
authors.forename: Teele
authors.initials: T
authors.lastname: Kuusk
authors.affiliation: Department of Surgery and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 21, 90029 OYS, Oulu, Finland. fausto.biancari@ppshp.fi.
authors.forename: Fausto
authors.initials: F
authors.lastname: Biancari
authors.affiliation: Division of Urology, Michigan State University, Grand Rapids, Michigan, USA. blaneppmd@yahoo.com.
authors.forename: Brian
authors.initials: B
authors.lastname: Lane
authors.affiliation: Division of Urology, Michigan State University, Grand Rapids, Michigan, USA. conrad.tobert@gmail.com.
authors.forename: Conrad
authors.initials: C
authors.lastname: Tobert
authors.affiliation: Department of Urology, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio, USA. CAMPBES3@ccf.org.
authors.forename: Steven
authors.initials: S
authors.lastname: Campbell
authors.affiliation: Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel. Uri.Rimon@sheba.health.gov.il.
authors.forename: Uri
authors.initials: U
authors.lastname: Rimon
authors.affiliation: Department of Surgery and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 21, 90029 OYS, Oulu, Finland. vito.dandrea@uniroma1.it.
authors.forename: Vito
authors.initials: V
authors.lastname: D'Andrea
authors.affiliation: Department of Surgery and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 21, 90029 OYS, Oulu, Finland. aare.mehik@oulu.fi.
authors.forename: Aare
authors.initials: A
authors.lastname: Mehik
authors.affiliation: Department of Surgery and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 21, 90029 OYS, Oulu, Finland. markku.vaarala@oulu.fi.
authors.forename: Markku H
authors.initials: MH
authors.lastname: Vaarala
mesh_terms: D000328:Adult; D000368:Aged; D018207:Angiomyolipoma / Q000150:complications / Q000473:pathology / Q000628:therapy*; D017115:Catheter Ablation; D003452:Cryosurgery; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000150:complications / Q000473:pathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D016896:Treatment Outcome