Diagnosis of Hydronephrosis or Ureteral Obstruction using Renal Sonography among Patients with Cervical Cancer
Background. Cervical cancer is the second most common malignancy among Filipino women. The recent 2018 FIGO guidelines recommend imaging in cases of grossly invasive disease to determine the presence of hydronephrosis, which would immediately classify the disease as at least stage IIIB. CT and MRI are state-of-the-art modalities that can provide such information; however, these are costly and may not be accessible in areas with limited resources. Sonography is a safe and inexpensive alternative in this regard.
Objective. This study aimed to evaluate the diagnostic performance of renal sonography in identifying the presence of ureteral obstruction or hydronephrosis among patients with grossly invasive cervical cancer, with non-enhanced CT as the reference standard.
Methods. A blinded, prospective study was conducted among patients diagnosed with grossly invasive cervical cancer from the Philippine General Hospital. Participants underwent same-day evaluation with both renal sonography and non-enhanced CT. The presence of either ureteral obstruction or hydronephrosis secondary to cervical cancer was independently determined. The sensitivity, specificity, positive predictive value, and negative predictive value of renal sonography were calculated, with non-enhanced CT as the reference standard.
Results. A total of 127 participants were enrolled. The mean age was 46 years, with a range of 24 to 65 years. The majority had stage IIB (41.7%) and stage IIIB (52.0%) disease. On non-enhanced CT, 46 (36.2%) showed evidence of ureteral obstruction or hydronephrosis, while 81 (63.8%) had negative results. On renal sonography, 46 (36.2%) had positive results, and 81 (63.8%) had negative findings. The sensitivity, specificity, and positive and negative predictive values of sonography were 91.3%, 95.1%, 91.3%, and 95.1%, respectively. Among patients with stage IIIB disease, sonography was shown to have higher sensitivity and specificity of 92.1% and 96.4%, respectively. Meanwhile, among patients with stage IB to IIB disease, its sensitivity and specificity were 87.5% and 94.3%, respectively.
Conclusion. Renal sonography has high sensitivity and specificity in the diagnosis of ureteral obstruction or hydronephrosis in patients with grossly invasive cervical cancer. Its sensitivity is higher when used in patients with stage IIIB disease, compared with those having lower-stage tumors.