Serum urea nitrogen and creatinine changes and its clinical significance in children with retinoblastoma before and after chemotherapy

Objective\r\nTo analyze the alterations in blood urea nitrogen (BUN) and serum creatinine (Scr) in children with retinoblastoma(Rb) before and after chemotherapy and the clinical significance of the chemotherapy effect, and to provide the evidence for the further improvement of the safety of treatment.\r\n\r\n\r\nMethods\r\nA total of 280 children with Rb were enrolled in the study, and each of them was treated with CEV (Carboplatin+ Etoposide+ Vincristine) methods.There subjects included 153 males and 127 females, with a mean treatment of 4.5 cycles (range 2 to 12 cycles) and a mean age of 21.5 months (range 1 to 84 months). Among them, 149 cases were diagnosed clinically, 131 cases were diagnosed pathologically.Eight cases were in the extraocular stage, 3 cases were in glaucoma and 269 cases in intraocular period(101 cases of single eyes and 168 cases of double eyes). BUN and Scr were detected before the first course of chemotherapy and after the last course of chemotherapy.\r\n\r\n\r\nResults\r\nBUN and Scr values were analyzed before and after chemotherapy.BUN was 3.05 mmol/L before chemotherapy and 3.46 mmol/L after chemotherapy in the group aged from 4 months to less than 12 months (73 cases), the values of BUN after chemotherapy was higher than that before chemotherapy, and only in this group the change was statistically different (t=-2.829, P=0.006), but all BUN values in this group were not beyond the highest reference value(1.70 mmol/L-7.10 mmol/L). Before initial chemotherapy, 149 patients(53.2%) had Scr below the reference range(male: 30-104 μmol/L, female: 30-84 μmol/L), and 20 cases(7.0%) had the BUN below the reference value.In 2 cases, BUN(7.25 mmol/L and 7.34 mmol/L, respectively)before the initial chemotherapy was slightly higher than the normal value, but the value was normal(5.01 mmol/L and 4.98 mmol/L, respectively)after the last chemotherapy.In one case, the BUN(5.62 mmol/L)was normal before the initial chemotherapy, but it was elevated(7.33 mmol/L) after the last chemotherapy.In another one case, the BUN was normal before and after chemotherapy, but the value after chemotherapy was 4.69 times higher than that before chemotherapy.\r\n\r\n\r\nConclusions\r\nRenal function of Rb children before treatment is normal.Seven percent of these patients have BUN under the BUN reference range, and 53.2% of these patients have Scr under the Scr reference range.It suggested that the reference values of BUN and Scr need to be adjusted.BUN of infant Rb may increase significantly after chemotherapy, but it does not meet the current diagnostic criteria of mild nephrotoxicity.Still, the early renal damage needs to be noticed.\r\n\r\n\r\nKey words: \r\nRetinoblastoma; Blood urea nitrogen; Serum creatinine; Clinical significance; Chemotherapy