Understanding the principles in management of Wilms' tumour: can imaging assist in patient selection?

P B, Ramadwar M, Singh S, Shukla A, Panwala H, Sahu A, Siddharth L, Kapadia T. Imaging Recommendations for Diagnosis, Staging, and Management of Pediatric Solid Tumors

Paediatric extra-cranial solid tumours are one of the common causes for paediatric malignancies. Lack of appropriate imaging at presentation, staging and for follow-up is a major challenge for paediatric solid tumours. We have reviewed the paediatric solid tumour imaging protocols suggested by the major oncological societies/groups around the world (mainly the SIOP – Society International Pediatric Oncology, and the COG – Children's Oncology Group). We have adapted some of those protocols to develop imaging recommendations for the diagnosis, staging and management of extra-cranial solid tumours based on the treatment protocols followed in India.

Diffusion-weighted MRI and histogram analysis: assessment of response to neoadjuvant chemotherapy in nephroblastoma

Purpose

To assess the value of diffusion-weighted MRI (DW-MRI) in the non-invasive prediction of blastemal remnant after neoadjuvant chemotherapy in nephroblastoma.

Methods

This IRB-approved study included 32 pediatric patients with 35 tumors who underwent DW-MRI prior and after completion of neoadjuvant chemotherapy and subsequent surgical resection. Two blinded radiologists volumetrically assessed each tumor on pre- and post-neoadjuvant images and the parameters mean ADC, median ADC, 12.5th/25th/75th ADC percentile, skewness, and kurtosis were calculated. Blastemal remnant was determined per the pathology report. Associations between imaging features and blastemal remnant quartiles were examined using the Kruskal–Wallis test and adjusted for false discovery rate.

Results

Inter-reader agreement was high for mean ADC, skewness, kurtosis, and volume (ICC: 0.76–0.998). Pre-therapeutic histogram parameters skewness and kurtosis were found to be higher in patients with a higher amount of blastemal remnant for reader 1 (overall p = 0.035) and for kurtosis in reader 2 (overall p = 0.032) with skewness not reaching the level of statistical significance (overall p = 0.055). Higher tumor volume on pre-treatment imaging was associated with a higher amount of blastemal remnant after therapy (overall p = 0.032 for both readers).

Conclusions

Pre-treatment skewness and kurtosis of ADC histogram analysis were significantly associated with a larger fraction of a blastemal remnant after neoadjuvant chemotherapy. These findings could be incorporated into a more personalized chemotherapeutic regime in these patients and offer prognostic information at the time of initial diagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00261-021-03032-9.

Wilms or non-Wilms tumors? Imaging features of renal tumors in pediatrics

Introduction: Identifying the imaging features of renal tumors in pediatric population allows reaching more accurate diagnoses and implementing more appropriate treatments. Objective: To describe the imaging findings of renal tumors in children and to assess the association between imaging findings and histological diagnosis of Wilms tumors versus Non-Wilms tumors, and between imaging features and intraoperative rupture of Wilms tumors, as well as the level of agreement between radiological and histological diagnosis (Wilms vs. Non-Wilms tumor). Materials and methods:  Cross-sectional study conducted in 47 children with a kidney tumor pathological diagnosis treated between 2012 and 2018 in a pediatric hospital in Bogotá, Colombia. The patients’ medical records, as well as their ultrasound, tomography and magnetic resonance studies were reviewed. Two univariate logistic regression analyses were performed to assess the association between imaging findings and histopathological diagnosis and between imaging features and intraoperative rupture of Wilms tumors, calculating the respective Odds Ratio (OR) with a 95% confidence interval. In addition, the level of agreement between radiological and histological diagnosis was determined using the Kappa coefficient. Results: A significant association was found between histological diagnosis of Wilms tumor and the presence of necrosis, tumor enhancement, pseudocapsule, rupture signs, tumor volume and tumor size (OR: 21.6, 15.17, 14.57, 8.21, 7.93 and 4.37, respectively; p<0.05). An association between having Wilms tumor and lower frequency of metastases was also found (OR: 0.19; p<0.05). The Kappa coefficient between radiological diagnosis of Wilms/non-Wilms tumors and histological findings was 0.78 (95%CI: 0.59-0.96; p<0.05). Additionally, Wilms tumors volume was significantly associated with the occurrence of rupture (OR: 3.08; p<0.05). Conclusions: There are imaging findings such as necrosis, tumor enhancement and tumor volume that can help predict the histological diagnosis and intraoperative rupture risk of Wilms tumors.

Volumetric assessment of unaffected parenchyma and Wilms' tumours: analysis of response to chemotherapy and surgery using a semi-automated segmentation algorithm in children with renal neoplasms

OBJECTIVE

To present our proof of concept with semi-automatic image recognition/segmentation technology for calculation of tumour/parenchyma volume.

METHODS

We reviewed Wilms' tumours (WTs) between 2000 and 2018, capturing computed tomography images at baseline, after neoadjuvant chemotherapy (NaC) and postoperatively. Images were uploaded into MATLAB-3-D volumetric image processing software. The program was trained by two clinicians who supervised the demarcation of tumour and parenchyma, followed by automatic recognition and delineation of tumour margins on serial imaging, and differentiation from uninvolved renal parenchyma. Volume was automatically calculated for both.

RESULTS

During the study period, 98 patients were identified. Of these, based on image quality and availability, 32 (38 affected moieties) were selected. Most patients (65%) were girls, diagnosed at age 50 ± 37 months of age. NaC was employed in 64% of patients. Surgical management included 27 radical and 11 partial nephrectomies. Automated volume assessment demonstrated objective response to NaC for unilateral and bilateral tumours (68 ± 20% and 53 ± 39%, respectively), as well as preservation on uninvolved parenchyma with partial nephrectomy (70 ± 46 cm³ at presentation to 57 ± 41 cm³ post-surgery).

CONCLUSION

Volumetric analysis is feasible and allows objective assessment of tumour and parenchyma volume in response to chemotherapy and surgery. Our data show changes after therapy that may be otherwise difficult to quantify. Use of such technology may improve surgical planning and quantification of response to treatment, as well as serving as a tool to predict renal reserve and long-term changes in renal function.

Customized approach for upfront or delayed resection using radiological criteria in unilateral, nonmetastatic pediatric renal tumors: A prospective study

BACKGROUND

The availability of robust, equivalent data regarding outcomes for upfront or delayed surgery for renal tumors in children leads to a dilemma in selecting the initial treatment. Imaging criteria associated with the probability of rupture or incomplete resection may provide a more objective assessment for customization for the timing of surgery.

PROCEDURE

Eighty-three children with unilateral, nonmetastatic renal tumors were enrolled between January 2012 and April 2018. Upfront nephrectomy was performed in the absence or delayed surgery (after a biopsy and chemotherapy) in the presence of one or more imaging-based high-risk features, including perinephric spread or adjacent organ infiltration, tumors crossing the midline, intravascular thrombus, and extensive adenopathy. Post hoc analysis for interobserver concordance for high-risk imaging features was also performed.

RESULTS

The upfront surgery group (19) had predominantly stage I or II diseases (89%) and the histological types were Wilms (13), non-Wilms (5) renal tumor, and an inflammatory lesion. The delayed surgery group had 60% with stage I or II diseases and the histological types were Wilms (60) and non-Wilms (4) tumor. In addition, high-risk pathology was identified in nine patients. Overall, 27 patients with Wilms tumors required radiotherapy and anthracycline because of stage III disease, including one in the immediate surgery group. The event-free and overall survival (OS) at a median follow-up of 39 months for Wilms tumor are 88% (95% confidence interval [CI]: 78.5-94.9%) and 89% (95% CI: 81.4-96.6%), 85.1% (95% CI: 73.8-93.4%) and 86.5% (95% CI: 77.4-95.8%) for the delayed, and 100% event-free survival as well as OS (P = .1) in the upfront surgery group.

CONCLUSION

A customized approach pivoted on image-based high-risk features facilitates identification of patients with early-stage renal tumor when the timing of surgery is tailored. Moreover, non-Wilms tumor and high-risk pathology are also identified.

[Wilms' tumour: A review of 15 years recent experience]

INTRODUCTION

Wilms' tumour is the most frequent renal tumour in children. Multi-modal treatment includes chemotherapy and surgery, with or without radiotherapy. The survival is excellent, with rates exceeding 90%. A review is presented on our experience over the last 15 years of treating Wilms' tumour in Hospital Niño Jesús, Madrid.

PATIENTS AND METHODS

A retrospective study was conducted on 40 consecutive paediatric patients diagnosed with nephroblastoma between 2002 and 2016 in the Hospital Niño Jesús in Madrid. The clinical characteristics, diagnostic methods, treatment, and follow-up were analysed.

RESULTS

Of the 40 patients, 23 were boys, with a median age at diagnosis of 2.5 years (range, 4 months-15 years). Three patients underwent initial nephrectomy, three received a fine needle aspiration biopsy, followed by chemotherapy, and 34 patients started pre-operative chemotherapy directly. The median follow-up of the patients was 6.75 years (range, 10 months - 13.92 years). Two patients died from disease progression. There were no treatment-related deaths. Overall survival and event-free survival at 5 years was 94.6±3.7% and 89.4±5%, respectively.

CONCLUSION

Wilms' tumour treatment is a success of modern medicine, currently achieving a survival rate of 95% in our series.

Initial Surgery in Tailoring Treatment for Children With Stage II and III Wilms' Tumor: An Experience From Resource Challenged Settings

BACKGROUND

Although Wilms' tumor (WT) is ranked first among primary childhood's renal neoplasm, controversy still exists regarding the best approach for its management. The study aimed at evaluating the role of initial surgery in treatment of stage II and III pediatric WT as a part of the short administration schedule as in National Wilms' Tumor Study (NWTS)-4 and evaluating its effectiveness compared to the long administration schedule.

METHODS

The study included 30 children who were primarily diagnosed as stage II and III WT. They were divided into two equal groups. Group I (n = 15) included those children who had undergone neoadjuvant chemotherapy followed by surgery and postoperative chemotherapy, while group II (n = 15) included those children who had undergone primary surgery as an initial management followed by chemotherapy. After a mean postoperative follow-up period of 14 ± 5 months, clinical and radiological evaluation was performed to all patients.

RESULTS

In group I, 10 patients were preoperatively diagnosed as stage II and five patients as stage III while in group II, 11 patients were proved to be stage II and four patients were stage III. After a follow-up period, clinical and radiological evaluation using CT was performed to all patients. In patients with stage II, evidence of recurrence was noted in three patients of group I whereas no patient showed any evidence of recurrence in group II. In patients with stage III, rebound increase in size was seen in two patients in group I and only one patient in group II.

CONCLUSIONS

Initial surgical intervention with appropriate adjuvant therapy has better outcomes than the neoadjuvant chemotherapy and delayed surgery for children primarily diagnosed as stage II and III WT. Moreover, it may act as a short administration schedule for the treatment as it is not less effective than the long administration schedule and can be administered at a substantially lower total treatment cost.

Neuroblastoma and nephroblastoma: a radiological review

Neuroblastoma (NBL) is the most common extra-cranial tumour in childhood. It can present as an abdominal mass, but is usually metastatic at diagnosis so the symptomatology can be varied. Nephroblastoma, also more commonly known as a Wilms tumour, is the commonest renal tumour in childhood and more typically presents as abdominal pathology with few constitutional symptoms, although rarely haematuria can be a presenting feature. The pathophysiology and clinical aspects of both tumours including associated risk factors and pathologies are discussed. Oncogenetics and chromosomal abnormalities are increasingly recognised as important prognostic indicators and their impact on initial management is considered. Imaging plays a pivotal role in terms of diagnosis and recent imaging advances mean that radiology has an increasingly crucial role in the management pathway. The use of image defined risk factors in neuroblastoma has begun to dramatically change how this tumour is characterised pre-operatively. The National Wilms Tumour Study Group have comprehensively staged Wilms tumours and this is reviewed as it impacts significantly on management. The use of contrast-enhanced MRI and diffusion-weighted sequences have further served to augment the information available to the clinical team during initial assessment of both neuroblastomas and Wilms tumours. The differences in management strategies are outlined. This paper therefore aims to provide a comprehensive update on these two common paediatric tumours with a particular emphasis on the current crucial role played by imaging.

Can computerized tomography accurately stage childhood renal tumors?

PURPOSE

Staging of childhood renal tumors is crucial for treatment planning and outcome prediction. We sought to identify whether computerized tomography could accurately predict the local stage of childhood renal tumors.

MATERIALS AND METHODS

We retrospectively reviewed our database for patients diagnosed with childhood renal tumors and treated surgically between 1990 and 2013. Inability to retrieve preoperative computerized tomography, intraoperative tumor spillage and nonWilms childhood renal tumors were exclusion criteria. Local computerized tomography stage was assigned by a single experienced pediatric radiologist blinded to the pathological stage, using a consensus similar to the Children's Oncology Group Wilms tumor staging system. Tumors were stratified into up-front surgery and preoperative chemotherapy groups. The radiological stage of each tumor was compared to the pathological stage.

RESULTS

A total of 189 tumors in 179 patients met inclusion criteria. Computerized tomography staging matched pathological staging in 68% of up-front surgery (70 of 103), 31.8% of pre-chemotherapy (21 of 66) and 48.8% of post-chemotherapy scans (42 of 86). Computerized tomography over staged 21.4%, 65.2% and 46.5% of tumors in the up-front surgery, pre-chemotherapy and post-chemotherapy scans, respectively, and under staged 10.7%, 3% and 4.7%. Computerized tomography staging was more accurate in tumors managed by up-front surgery (p <0.001) and those without extracapsular extension (p <0.001).

CONCLUSIONS

The validity of computerized tomography staging of childhood renal tumors remains doubtful. This staging is more accurate for tumors treated with up-front surgery and those without extracapsular extension. Preoperative computerized tomography can help to exclude capsular breach. Treatment strategy should be based on surgical and pathological staging to avoid the hazards of inaccurate staging.