External validation of the paediatric risk of malignancy index

Abstract

Objective This study aimed to validate the paediatric risk of malignancy index (PRMI), as previously published.Design External validation study.Setting Academic hospital: Radboud University Medical Center.Population Female paediatric patients under the age of 18 years diagnosed with, or treated for, an adnexal mass between January 1999 and October 2013.Methods Information was collected on diagnosis, presenting symptoms, and signs and imaging characteristics. The PRMI was calculated for each patient. Sensitivity, specificity, and positive and negative predictive values were calculated, and the results were visualised using a receiver operating characteristic curve (ROC curve).Main outcome measures Histological diagnosis, discriminative performance using the area under the curve (AUC) of the ROC curve and sensitivity and specificity.Results Seventy-eight patients were included, with a median age of 12 years. A malignant mass was found in 17 patients (21.8%). The PRMI with a cut-off value of 7 resulted in a sensitivity of 70.1% (95% CI 44.1-89.6%) and a specificity of 85.3% (95% CI 73.8-93.0%). The area under the ROC curve was 0.868 (95% CI 0.756-0.980).Conclusions The PRMI showed less discriminative capacity than originally published, but its performance was still good; however, further prospective validation studies are needed to define whether the model is useful in daily clinical practice.

Ovarian masses in the child and adolescent: An American Pediatric Surgical Association Outcomes and Evidence-Based Practice Committee systematic review

“…Ultrasound scoring systems which combine size and intrinsic mass characteristics have been developed to increase the sensitivity, specificity, and accuracy of ultrasound as a preoperative screening modality for malignancy. Five studies evaluated ovarian scoring systems applicable to a pediatric population (Table 2) [17][18][19][20][21]. In a retrospective study of 121 pediatric and adult patients, DePriest et al described and validated an ultrasound morphology index which included descriptions of the volume, wall structure, and septations.…”

“…Unfortunately, additional validation of this index showed poorer performance with an accuracy of 82.1% and a PPV of 57.1% and NPV of 91.2%. [21]. Therefore, as with other preoperative indicators, malignancy indices are a helpful adjunct in preoperative risk stratification but do have limitations and should be used with other assessment measures.…”

Re: External validation of the Paediatric Risk of Malignancy Index

“…We appreciate the external validation of the Paediatric Risk of Malignancy Index (PRMI) reported by Hermans et al., and are pleased that the results of the index were reproducible in a different ethnic population. Interestingly, a higher rate of false positives was encountered due to large mature teratomas with large solid components (Table ).…”

“…1,2 As the original article described only the maximum diameter of the largest 'solid component' as a factor we measured the largest diameter of the area described as solid component by the radiologist. When detailed information …”

Author's reply re: External validation of the paediatric risk of malignancy index

“…We thank Dr Loh and colleagues for their interest in our paper and are pleased to respond to their letter regarding our external validation of the Paediatric Risk of Malignancy Index (PRMI) …”