Radiation therapy

The kidney is relatively radiosensitive, with a tolerance dose of 20 Gy.[22]

Doses of 18 Gy are considered unlikely to cause severe or chronic renal sequelae. In contrast, up to 50% of individuals treated with 20 Gy may develop glomerular dysfunction or hypertension within 20 years.[23]

Specific quantitative data are sparse, but a study of 108 children treated for Wilms tumor who had undergone unilateral nephrectomy showed that 41% of children who received less than 12 Gy of radiation to the contralateral remaining kidney, 56% of children who received 12 Gy to 24 Gy, and 91% of children who received more than 24 Gy had a decreased creatinine clearance (GFR <63 mL/min/m2).[24]

In a report from the German Registry for the Evaluation of Side Effects after Radiation in Childhood and Adolescence (RISK consortium), 126 patients who underwent radiation therapy to parts of the kidneys for various cancers were evaluated. All patients had also received potentially nephrotoxic chemotherapy. Whole-kidney volumes exposed to greater than 20 Gy (P = .031) or 30 Gy (P = .003) of radiation were associated with a greater risk of nephrotoxicity.[25]

Risk factors for radiation injury include the following:

Risk factors for radiation injury include the following:

Age at time of radiation therapy.

Risk factors for radiation injury include the following: › Age at time of radiation therapy.

Neonates appear to have an increased sensitivity to radiation therapy; doses of 12 Gy to 24 Gy at 1.25 Gy to 1.5 Gy per fraction to the entire kidney were associated with a decreased GFR.[26]

Risk factors for radiation injury include the following: › Age at time of radiation therapy.

However, for older children, there is no convincing evidence that age at the time of radiation therapy is related to renal injury.[26]

Risk factors for radiation injury include the following:

Unilateral versus bilateral radiation therapy.

Risk factors for radiation injury include the following: › Unilateral versus bilateral radiation therapy.

In the National Wilms Tumor Study experience, renal failure was more common in children with bilateral tumors than in children with unilateral tumors.[27]

Risk factors for radiation injury include the following: › Unilateral versus bilateral radiation therapy.

The effects of radiation also depend on whether partial or whole-kidney radiation therapy is administered. Renal failure is rare after the administration of partial-volume radiation doses between 12 Gy and 27 Gy.[28]

Risk factors for radiation injury include the following: › Unilateral versus bilateral radiation therapy.

When certain agents such as cyclosporine and teniposide are not used, TBI doses of up to 13 Gy are associated with a less than 8% incidence of kidney toxicity.[29]

Risk factors for radiation injury include the following:

HSCT.

Risk factors for radiation injury include the following: › HSCT.

Chronic kidney disease is a long-term complication of HSCT that has been variably associated with acute kidney injury, lower pretransplant renal function, TBI, conditioning regimens such as fludarabine, graft-versus-host disease, and use of calcineurin inhibitors.[30-32]

Risk factors for radiation injury include the following: › HSCT.

Most reports of renal outcomes among long-term survivors of childhood cancer treated with HSCT are limited to descriptive outcomes of very small cohorts.

Risk factors for radiation injury include the following: › HSCT.

For more information, see the Urinary System Late Effects section in Complications, Graft-Versus-Host Disease, and Late Effects After Pediatric Hematopoietic Stem Cell Transplant.

The risk of toxicity from 10.5 Gy whole-abdomen irradiation was low among patients with Wilms tumor (risks of ≥grade 2 toxicity, 4% and risks of ≥grade 3 toxicity, 1%).

For fractionated 12-Gy TBI with various combinations of chemotherapy, the risk of severe toxicity was low, but low-grade toxicity was more common (risks of ≥grade 2 toxicity, 8% and risks of ≥grade 3 toxicity, 3%).

With a cisplatin dose of 480 mg/m2, a 3% risk of grade 3 or higher toxicity occurred without radiation, and a 5% risk when 26% of the kidney received 10 Gy or higher.

With an ifosfamide dose of 63 g/m2, a 5% risk of grade 3 or higher toxicity occurred without radiation, and a 10% toxicity risk occurred when 42% of the kidney received 10 Gy or higher.