title: The roles of serum and urinary carbohydrate antigen 19-9 in the management of patients with antenatal hydronephrosis.
abstract: BACKGROUND
  Serum carbohydrate antigen (CA) 19-9 has been clinically applied as a valuable tumor marker for pancreatic and gastrointestinal carcinoma. CA 19-9 is expressed in normal excretory epithelium tissues. Increased CA 19-9 has also been observed in uroepithelial tumors as well as in nonmalignant conditions including hydronephrosis secondary to ureteral stones.
  
  
  OBJECTIVE
  The purpose of this article is to evaluate the role of urinary CA 19-9 as a non-invasive biomarker in the postnatal differentiation of obstructive and non-obstructive hydronephrosis in patients with unilateral antenatal hydronephrosis.
  
  
  METHODS
  Infants with isolated renal pelvic dilatation, defined as the presence of anteroposterior pelvic diameter (APPD) equal to or greater than 7 mm based on antenatal ultrasound after 28 weeks' gestation, underwent systematic investigation for uropathies and were prospectively followed up. The pyeloplasty group consisted of 17 patients with ureteropelvic junction (UPJ) obstruction who had undergone pyeloplasty. The non-obstructive dilatation (NOD) group consisted of 17 patients with non-obstructive hydronephrosis, and the control group consisted of 21 healthy children. Commercial enzyme-linked immunosorbent assay (ELISA) kits were used to measure the urinary and serum CA 19-9 levels. In both hydronephrosis groups (pyeloplasty and non-obstructive dilatation), the correlations between urinary and serum CA 19-9 levels with the anteroposterior pelvic diameter measured at the third trimester and the postnatal initial evaluation and differential renal function were investigated.
  
  
  RESULTS
  The initial median urinary CA 19-9 levels were significantly greater in children who underwent pyeloplasty than in both the non-obstructive hydronephrosis (143 ± 38 vs. 68 ± 23, respectively; p = 0.007) and the healthy control groups (143 ± 38 vs. 13 ± 3, respectively; p = 0.001) (Figure). Three months after surgery, the urinary CA 19-9 levels had decreased significantly according to the preoperative levels in the pyeloplasty group (143 ± 38 vs. 55 ± 16, p = 0.039). In both the pyeloplasty and NOD groups, there was a correlation of urinary CA 19-9 levels with differential renal function and a correlation of serum CA 19-9 levels with the initial anteroposterior pelvic diameter. Receiver operator characteristic (ROC) analysis revealed a better diagnostic profile for the urinary CA 19-9 level than for the serum CA 19-9 level in terms of identifying obstruction in the hydronephrosis groups (areas under the curve = 0.8 and 0.7, respectively). The best cut-off value of for urinary CA 19-9 was 85.5 U/mL with 76% sensitivity, 85% specificity. The negative predictive value was 80%.
  
  
  CONCLUSIONS
  The results suggest that voided urine CA 19-9 levels seems to be a more useful marker than serum CA 19-9 in obstructive dilatation. An appropriate decrease in urinary CA 19-9 levels after pyeloplasty may be used as a predictor of surgical outcome. In addition, the results have a number of important diagnostic implications that should be further validated in a larger study population.
  
  
  CONCLUSIONS
  Based on these results, we suggest that a high urinary CA 19-9 level is a non-invasive clinically applicable marker for differentiating between obstruction and non-obstructive dilatation.
authors.affiliation: Division of Pediatric Urology, Department of Urology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Arda
authors.initials: A
authors.lastname: Atar
authors.affiliation: Division of Pediatric Urology, Department of Urology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Tayfun
authors.initials: T
authors.lastname: Oktar
authors.affiliation: Department of Biochemistry, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Canan
authors.initials: C
authors.lastname: Kucukgergin
authors.affiliation: Division of Perinatology, Department of Obstetrics And Gynecology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Kalelioglu
authors.affiliation: Department of Biochemistry, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Sule
authors.initials: S
authors.lastname: Seckin
authors.affiliation: Division of Pediatric Urology, Department of Urology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Haluk
authors.initials: H
authors.lastname: Ander
authors.affiliation: Division of Pediatric Urology, Department of Urology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Ziylan
authors.affiliation: Division of Pediatric Urology, Department of Urology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey. Electronic address: tckadioglu@gmail.com.
authors.forename: Teoman Cem
authors.initials: TC
authors.lastname: Kadioglu
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D018395:CA-19-9 Antigen / Q000097:blood* / Q000652:urine*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000209:etiology / Q000378:metabolism* / Q000628:therapy*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011296:Prenatal Diagnosis; D012680:Sensitivity and Specificity; D014517:Ureteral Obstruction / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D018395:CA-19-9 Antigen
keywords: CA 19-9; Hydronephrosis; Ureteropelvic junction obstruction; Urinary biomarkers