Radiation nephropathy

Radiation nephropathy

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  Radiation Nephropathy By: A.Haghbin
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  kidneys  responsible forproducing erythropoietin to stimulate red blood cell production filtering waste metabolites and electrolytes from the blood modulating blood pressure by fluid/electrolyte balance
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  Radiation Nephropathy Radiation nephropathyis renal injury and loss of function caused by ionizing radiation. Radiation nephropathy occurs as a late phenomenon, usually presenting months to years after the radiation exposure. Normal renal tissue has lowmitotic rates, which correlate with delayed expression of renal injury after radiation
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  CLINICAL PRESENTATION The clinicalfeatures of radiation nephropathy will vary according to dose and volume of irradiation. Acute radiation nephritis Chronic radiation nephritis
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  Acute radiation nephritis Mostcommonly occurs 6-12 months after exposure. Signs and symptoms: Malignant Hypertension, degrees of edema, proteinuria, severe anemia disproportionate( microangiopathic hemolytic anemia), thrombocytopenia, azotemia Patients surviving this acute phase usually are left with progression to CKD.
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  Chronic radiation nephritis Mostcommonly occurs ≥18 months after exposure. There are two variants of chronic nephritis: -Primary chronic radiation nephritis -secondary chronic radiation nephritis Signs and symptoms: hypertension, albuminuria, anemia, azotemia, small atrophic kidneys
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  Histopathology Early changes include: endothelialmicrovascularinjury with cell swelling, subendothelial expansion, capillary loop occlusion, mesangiolysis and variable tubular injury Late changes include: sclerosis of interlobular and arcuate arteries, residual parenchymal damage, increased mesangial matrix, glomerular scarring, tubular atrophy, and renal mass reduction.
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  Arteriolonephrosclerosis, glomerular tuftsof/erent arterioles rapid endothelial swelling and proliferation, slower thickening walls arte./vein hypertension
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  Functional subunit The FSUis the minimum unit that can function independently of the remaining organ. Thus, the observed global sensitivity of an organ will depend on the inherent sensitivity of the target cells, as well as the number of target cells within a FSU. In the kidney: nephron has a proximal tubule, loop of Henle, the distal tubule that are dependent on each other.
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  Organizational structure betweenFSUs A related consideration is the manner in which FSUs are ‘connected to each other’ to yield the overall organ function Normal organs can be broadly classified : - parallel architecture - series architecture Kidney is parallel organ.
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  Distribution of Function Organscan be considered to have homogeneous versus heterogeneous function throughout. Association between concepts of parallel versus series and heterogeneous versus homogeneous function
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  Endpoint Assessment Laboratory Findings: CBC(microangiopathichemolytic anemia ,Thrombocytopenia,..), urinalysis , creatinine , glomerular filtration rate (GFR)or CrCl , blood urea nitrogen (BUN).  Radiological findings : ultrasound , CT , MRI , SPECT/CT, 99mTC dimercaptosuccinyl acid renography
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  Tolerance dose effect ReferenceWholeor partial organ TD5/50TD5/5InjuryClass I organs Kraut et al., Tefft Kunkler et al Whole (strip) Whole 2000 2500 1500 2000 Acute and chronic nephrosclerosis kidney  Class I— Organs in which radiation lesions are fatal or result in severe morbidity
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  Parameters of therapy:tolerance doses (TD5/5–TD50/5) Fractionated dose (Gy) Single dose (Gy) 20-3010-20  Dose-limiting organs and tissues in radiation oncology have been defined according to their tolerance dose Dose range (Gy) TD5/5–TD50/5 Complication end pointTarget cell 23-28ArterionephrosclerosisKidney-glomeruli
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  QUANTEC Summary: Notes on dose/volume parameter Rate(%)Dose(Gy), dose/volume parameters EndpointIrradiation type Volume segmented kidney <5Mean dose<15-18 Clinically relevant renal dysfunction Bilateral whole oragan or 3D-CRT Bilateral whole <50Mean dose<28Clinically relevant renal dysfunction Bilateral whole oragan Bilateral whole For combined kidney < 5V12< 55% V20< 32% V23< 30% V28< 20% Clinically relevant renal dysfunction 3D-CRTBilateral whole
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  Reference • Rubin P,Constine LS, Marks LB. ALERT-Adverse Late Effects of Cancer Treatment. Springer; 2014. • Podoll AS, Amsbaugh MJ. Radiation-associated Kidney Injury. InRenal Disease in Cancer Patients 2014 (pp. 105-113). • May KS, Khushalani NI, Chandrasekhar R, Wilding GE, Iyer RV, Ma WW, Flaherty L, Russo RC, Fakih M, Kuvshinoff BW, Gibbs JF. Analysis of clinical and dosimetric factors associated with change in renal function in patients with gastrointestinal malignancies after chemoradiation to the abdomen. International Journal of Radiation Oncology* Biology* Physics. 2010 Mar 15;76(4):1193-8. • Baradaran-Ghahfarokhi M. Radiation-induced kidney injury. Journal of renal injury prevention. 2012;1(2):49. • Chapter 10: Radiation Nephropathy; Amaka Edeani, MBBS,* and Eric P. Cohen, MD • Lopez-Gaitan J, Ebert MA, Robins P, Boucek J, Leong T, Willis D, Bydder S, Podias P, Waters G, O’Mara B, Chu J. Radiotherapy of abdomen with precise renal assessment with SPECT/CT imaging (RAPRASI): design and methodology of a prospective trial to improve the understanding of kidney radiation dose response. BMC cancer. 2013 Dec;13(1):381.