Should functional renal scans be obtained prior to upper abdominal IMRT for pancreatic cancer?

Publication date: Available online 29 June 2017
Source:Practical Radiation Oncology
Author(s): GC. Blitzer, WA. Hall, S. Tsai, M. Aldakkak, RS. Hellman, DB. Evans, KK. Christians, B. George, PS. Ritch, BA. Erickson
BackgroundUpper abdominal irradiation for pancreas cancer is given in close proximity to the radiation sensitive kidneys. There is difficulty defining dose-volume parameters to predict late renal toxicity after partial kidney irradiation. Less than 10% of the general population is estimated to have asymmetrical kidney function; however, there are no studies examining this in patients with pancreatic cancer. The primary purpose of this study was to determine the prevalence of asymmetrical kidney function in patients with pancreatic cancer. A secondary aim was to determine if asymmetrical kidney function was associated with abnormal laboratory values or kidney size on CT scans. Finally, we aimed to develop recommendations for ordering a functional renal scan in patients with pancreatic cancer.MethodsWe performed a retrospective review of patients with resectable, borderline resectable and locally advanced pancreatic cancer who received abdominal radiation therapy and had pre-radiation functional renal scans between 2009–2015. Asymmetrical kidney function was defined as a difference between the two kidneys that was ≥60%/40% on a functional renal scan. Serum studies (BUN, Cr, GFR) and abdominal CT scans were routinely obtained pre-simulation.ResultsOf the 204 patients examined, 23 (11.2%) had asymmetrical kidney function identified on pre-radiation functional renal scans. Elevated Cr or BUN, a GFR<60, or a past medical history suggesting abnormal renal function were not significantly associated with asymmetrical kidney function. Only six (26%) of the 23 patients with asymmetrical kidney function had a notable difference in kidney size.ConclusionsIn our series, approximately 11% of patients with pancreatic cancer have asymmetrical kidney function not identified by kidney size, serum BUN, Cr, GFR, or a significant past medical history. These data suggest that in cases where renal radiation doses exceed a V18 of 20–30%, or there is concern about baseline renal function, a functional renal scan should be considered.



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