Impact of stereotactic radiotherapy on kidney function in primary renal cell carcinoma: Establishing a dose-response relationship

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• 作者：Shankar Siva^a ; ^b ; ^{shankar.siva@petermac.org" class="auth_mail" title="E-mail the corresponding author} ; Price Jackson^a ; Tomas Kron^a ; ^b ; Mathias Bressel^c ; Eddie Lau^a ; ^b ; ^d ; Michael Hofman^a ; ^b ; Mark Shaw^a ; Sarat Chander^a ; Daniel Pham^a ; Nathan Lawrentschuk^e ; Lih-Ming Wong^f ; Jeremy Goad^e ; Farshad Foroudi^a
• 关键词：SABR ; SBRT ; RCC ; Nephron sparing ; Creatinine ; Normal tissue toxicity
• 刊名：Radiotherapy and Oncology
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：118
• 期：3
• 页码：540-546
• 全文大小：1393 K

文摘

To evaluate renal dysfunction after stereotactic ablative body radiotherapy (SABR) for inoperable primary renal cell carcinoma (RCC) using nuclear medicine assessments.

Materials and methods

In a prospective clinical trial, patients received single fraction renal SABR (26 Gy) for tumours <5 cm, or fractionated SABR (3 × 14 Gy) for tumours ⩾5 cm. Global and regional glomerular filtration rate (GFR) was calculated through ⁵¹Cr-EDTA and ^99mTc-DMSA SPECT/CT, respectively, at baseline and post-treatment (14, 90 days and at 1-year). Regional loss in function was correlated to the absolute and biologically effective doses (BED) delivered.

Results

In 21 patients the mean (range) tumour size was 48 mm (21–75 mm). The mean ± SD GFR at baseline was 52 ± 24 ml/min. Net change in mean GFR was +0.6 ± 11.3, +3.2 ± 14.5 and −8.7 ± 13.4 ml/min (p = 0.03) at 2 weeks, 3 months and 1 year, respectively. For every 10 Gy of physical dose delivered, an exponential decline in affected kidney GFR was observed at 39% for 26 Gy/1 fraction and 25% for 42 Gy/3 fractions. When normalised to BED_3Gy, the dose–response relationship for each treatment prescription was similar with a plateau beyond 100 Gy. The R50% conformity index correlated with GFR loss (p = 0.04). No patient required dialysis.

Conclusions

SABR results in clinically acceptable and dose-dependent renal dysfunction at 1-year. Sparing functional kidney from high-dose regions (>50% isodoses) may help reduce risk of functional loss.