title: Stereotactic body radiotherapy of primary and metastatic renal lesions for patients with only one functioning kidney.
abstract: BACKGROUND
  About 2% of patients with a carcinoma in one kidney develop either metastases or a new primary tumor in the contralateral kidney. Often, renal cancers progress rapidly at peripheral sites and a metastasis to the second kidney may not be the patient's main problem. However, when an initial renal cancer is more indolent yet spreads to the formerly unaffected kidney or a new primary tumor forms there, local treatment may be needed. Stereotactic body radiotherapy (SBRT) has been demonstrated as a valuable treatment option for tumors that cause local symptoms. Presented here is a retrospective analysis of patients in whom SBRT was used to control primary or metastatic renal disease.
  
  
  METHODS
  Seven patients with a mean age of 64 (44-76) were treated for metastases from a malignant kidney to its contralateral counterpart. Dose/fractionation schedules varied between 10 Gy x 3 and 10 Gy x 4 depending on target location and size, given within one week. Follow-up times for patients who remained alive were 12, 52 and 66 months and for those who subsequently died were 10, 16, 49 and 70 months.
  
  
  RESULTS
  Local control, defined as radiologically stable disease or partial/complete response, was obtained in six of these seven patients and regained after retreatment in the one patient whose lesion progressed. Side effects were generally mild, and in five of the seven patients, kidney function remained unaffected after treatment. In two patients, the creatinine levels remained moderately elevated at approximately 160 micromol/L post treatment. At no time was dialysis required.
  
  
  CONCLUSIONS
  These results indicate that SBRT is a valuable alternative to surgery and other options for patients with metastases from a cancer-bearing kidney to the remaining kidney and provides local tumor control with satisfactory kidney function.
authors.affiliation: Department of General Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Svedman
authors.forename: Kristin
authors.initials: K
authors.lastname: Karlsson
authors.forename: Eva
authors.initials: E
authors.lastname: Rutkowska
authors.forename: P
authors.initials: P
authors.lastname: Sandström
authors.forename: H
authors.initials: H
authors.lastname: Blomgren
authors.forename: Ingmar
authors.initials: I
authors.lastname: Lax
authors.forename: Peter
authors.initials: P
authors.lastname: Wersäll
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000556:secondary / Q000601:surgery*; D018450:Disease Progression; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D007668:Kidney / Q000601:surgery*; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D016634:Radiosurgery; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome