Pediatric oncology surveillance imaging: two recommendations. Abandon CT scanning, and randomize to imaging or solely clinical follow-up

The significance of surveillance imaging in children with Ewing sarcoma and osteosarcoma

Primary bone tumors in children and adolescents, while rare, pose significant challenges in diagnosis and management. Children treated for Ewing sarcoma and osteosarcoma are offered a 5-year follow-up program after end of treatment, including radiological surveillance of primary location of tumor and the lungs. There is no consensus regarding how often and how the children should be followed with radiological imaging. This retrospective descriptive study of 69 patients (34 with Ewing sarcoma and 35 with osteosarcoma) investigated the consequences of abnormal findings in 1279 follow-up images. Nine relapses were detected, 4 in the Ewing group (3 local and 1 pulmonary) and 5 in the osteosarcoma group (1 local and 4 pulmonary). Of these, only two patients exhibited symptomatic relapses, with the remainder identified through imaging. The positive predictive value for relapse detection was 0.44 in the Ewing group, and 0.5 in the osteosarcoma group. In the Ewing sarcoma patient image follow-up program, the probability of anomaly detection was 12% (95% CI, 10-15). For osteosarcoma patients, the likelihood was 6% (95% CI, 4-8). Our data indicates that abnormal findings on follow-up images rarely represents relapse of tumor. As the surveillance protocol differs between the patient groups, wherein Ewing sarcoma patients primarily are monitored through MRI while osteosarcoma patients are predominantly tracked via X-rays, there is an increased occurrence of incidental findings in the first group. However, it is imperative to interpret imaging data in conjunction with clinical information, avoiding isolated reliance on imaging results when making treatment decisions.

Surgical Management and Outcomes of Pediatric Congenital Head and Neck Teratomas: A Scoping Review

Objective

To perform a scoping review to characterize postoperative outcomes of pediatric patients (ages 0-18) with a history of congenital head and neck teratomas.

Data Sources

PubMed, EMBASE, Web of Science, Cochrane, Clinicaltrails.gov.

Review Methods

A search of multiple databases was performed. Studies were included if they detailed the surgical management and outcomes of pediatric patients with a history of congenital head and neck teratomas.

Results

One hundred and eight studies totaling 137 patients were identified. The median gestational age at birth was 37 weeks. Respiratory distress, prompting emergent endotracheal intubation or tracheostomy, was present in most patients (58%). The ex utero intrapartum treatment (EXIT) procedure was utilized for 21 (15%) patients. The teratomas were resected after a median duration of 4 days from birth. The most common postsurgical complications were vocal cord paralysis (3%), hemorrhage (2%), and tracheomalacia (2%). Death occurred perioperatively in 2 patients (2%). Twenty-six patients (19%) required additional surgery, and 5 patients (4%) needed adjuvant chemotherapy. Patients were monitored for a median duration of 24 months with a recurrence rate of 6%. Four recurrent cases (50%) had intracranial extension, and 88% of the recurrent cases were mature teratomas at initial histopathological diagnosis.

Conclusion

Most patients with congenital head and neck teratomas require emergent airway management perinatally. Excisional and surgical complications are rare, and most patients are cured of their disease with a single operation. Recurrent teratomas tend to have an intracranial extension and are likely to be of mature pathology at the time of initial diagnosis.

Imaging of pediatric extremity soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

Pediatric soft tissue tumors of the extremity include rhabdomyosarcoma and nonrhabdomyosarcoma neoplasms. This manuscript provides consensus-based imaging recommendations for imaging evaluation at diagnosis, during treatment, and following completion of therapy for patients with a soft tissue tumor of the extremity.

Equivocal end-of-therapy imaging findings do not predict a higher risk of local relapse after definitive radiotherapy in pediatric Ewing sarcoma and rhabdomyosarcoma

BACKGROUND

Posttherapy imaging studies can provide reassurance or induce anxiety regarding risk of recurrence for patients and their families. In some cases, it is difficult to determine if imaging findings represent posttreatment changes or residual disease. Equivocal radiographic findings can occur due to therapy-related inflammation or residual, inactive soft tissue masses, but it is unknown if such findings indicate an increased likelihood of local recurrence. The aim of this study was to assess the value of initial posttherapy scans for predicting local relapse in patients with Ewing sarcoma (EWS) or rhabdomyosarcoma (RMS) who received radiotherapy (RT) for local control. These findings are critical to inform clinicians' surveillance recommendations and ability to accurately counsel patients and their families.

PROCEDURE

The primary endpoint was time to local progression (LP). Patients were classified as having posttherapy scans that were "positive" (residual disease within the RT field), "negative" (no evidence of residual disease within the RT field), or "equivocal" (no determination could be made). The value of initial posttreatment scans for predicting LP was assessed using positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

Negative imaging findings (n = 51) had an NPV of 88%, and positive imaging findings (n = 1) had a PPV of 100%. When equivocal findings (n = 16) were categorized with negative results (i.e., positive vs. equivocal/negative), the NPV was 90%. When equivocal findings were categorized with positive results (equivocal/positive vs. negative), the PPV was 12%.

CONCLUSION

Equivocal findings within the RT field on end-of-therapy imaging studies indicate no higher risk of local recurrence than negative findings. These results may contribute to appropriate surveillance schedules and accurate counseling of patients with RMS and EWS who have received RT for local control.

Relapse after non-metastatic rhabdomyosarcoma: The impact of routine surveillance imaging on early detection and post-relapse survival

BACKGROUND

Patients with rhabdomyosarcoma (RMS) whose disease relapses have little chance of being cured, so front-line treatments are usually followed up with surveillance imaging in an effort to detect any recurrences as early as possible, and thereby improve post-relapse outcomes. The real benefit of such routine surveillance imaging in RMS remains to be demonstrated, however. This retrospective, single-center study examines how well surveillance imaging identifies recurrent tumors and its impact on post-relapse survival.

METHODS

The analysis concerned 79 patients <21 years old treated between 1985 and 2020 whose initially localized RMS relapsed. Clinical findings, treatment modalities, and survival were analyzed, comparing patients whose relapse was first suspected from symptoms they developed (clinical symptoms group) with those whose relapse was identified by radiological surveillance (routine imaging group).

RESULTS

Tumor relapses came to light because of clinical symptoms in 42 cases, and on routine imaging in 37. The time to relapse was much the same in the two groups. The median overall survival (OS) and 5-year OS rate were, respectively, 10 months and 12.6% in the clinical symptoms group, and 11 months and 27.5% in the routine imaging group (p-value .327). Among patients with favorable prognostic scores, survival was better for those in the routine imaging group (5-year OS 75.0% vs. 33.0%, p-value .047).

CONCLUSION

It remains doubtful whether surveillance imaging has any real impact on RMS relapse detection and patients' post-relapse survival. Further studies are needed to establish the most appropriate follow-up recommendations, taking the potentially negative effects of regular radiological exams into account.

Relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas: The impact of routine imaging surveillance on early detection and post-relapse survival

PURPOSE

The chances of patients with relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) being cured are limited. This retrospective single-institutional study examines the potential role of routine surveillance imaging for detecting recurrent tumor, and its impact on post-relapse survival.

METHODS

The analysis concerned 86 patients < 21 years old with relapsing NRSTS treated from 1985 to 2020. Clinical findings, treatment modalities and survival were analyzed, comparing patients whose relapse was first suspected from symptoms (symptomatic group) with those whose relapse was detected by radiological surveillance (imaging group).

RESULTS

Tumor relapses were identified from clinical symptoms in 49 cases and on routine imaging in 37. Time to relapse was similar in the two groups. Routine imaging detected 6/32 local relapses and 31/48 distant relapses (and 79% of the cases of lung metastases). Overall survival (OS) at 5 years was 34.3% for the symptomatic group, and 24.0% for the imaging group (p-value 0.270). In patients with lung metastases at relapse, the 5-year OS was statistically better for the imaging group, that is, 25.8% versus 0% for the symptomatic group (p-value 0.044).

CONCLUSION

This is the first study to explore the role of surveillance imaging in pediatric NRSTS. Judging from our findings, the value of routine scanning of primary sites seems limited, while radiological surveillance may help to detect lung metastases, improving survival for this patient category. The potentially negative effects of periodic radiological exams should be considered in deciding the optimal follow-up for patients off therapy.

Is Detection of Relapse by Surveillance Imaging Associated With Longer Survival in Patients With Rhabdomyosarcoma?

BACKGROUND

We investigated whether surveillance imaging had an impact on post-relapse survival in patients with rhabdomyosarcoma (RMS). We hypothesized that relapse detected by imaging (group IM) would be associated with longer survival compared with relapse detected with a clinical sign or symptom (group SS).

MATERIALS AND METHODS

We performed an observational multi-institutional study in 127 patients with relapsed RMS comparing overall survival (OS) after relapse using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

Relapse was detected in 60 (47%) group IM and 67 (53%) SS patients. Median follow-up in survivors was 4 years (range 1.0 to 16.7 y). Four-year OS rates were similar between group IM (28%, 95% confidence interval [CI]: 14%-40%) and SS (21%, 95% CI: 11%-31%) ( P =0.14). In multivariable analyses accounting for institution, age at diagnosis, time to relapse, risk group at diagnosis, and primary site, not receiving chemotherapy (hazard ratio [HR]: 6.8, 95% CI: 2.8-16.6), radiation (HR: 3, 95% CI: 1.7-5.3), or surgery (HR: 2.8, 95% CI: 1.6-4.8) after relapse were independently associated with poor OS.

CONCLUSION

These results on whether surveillance imaging provides survival benefit in patients with relapsed RMS are inconclusive. Larger studies are needed to justify current surveillance recommendations. Chemotherapy, radiotherapy and surgery to treat recurrence prolong OS.

A systematic review of evidence for and against routine surveillance imaging after completing treatment for childhood extracranial solid tumors

BACKGROUND

Regular off-treatment imaging is often used to assess for recurrence of disease after childhood cancer treatment. It is unclear if this increases survival, or what burden surveillance places on patients, families, or health-care services. This systematic review examines the impact of routine surveillance imaging after treatment of pediatric extracranial solid tumors.

METHODS

Collaborative patient and public involvement informed the design and interpretation of this work. Thirteen electronic databases, conference proceedings, and trial registries were searched alongside reference list checking and forward citation searching from 1990 onwards. Studies were screened and data were extracted by two researchers. Risk of bias was assessed using a modified ROBINS-I tool. Relevant outcomes were overall survival, psychological distress indicators, number of imaging tests, cost-effectiveness, and qualitative data regarding experiences of surveillance programs. PROSPERO (CRD42018103764).

RESULTS

Of 17 727 records identified, 55 studies of 10 207 patients were included. All studies used observational methods. Risk of bias for all except one study was moderate, serious, or critical. Data were too few to conduct meta-analysis; however, narrative synthesis was performed. Surveillance strategies varied, and poorly reported, involving many scans and substantial radiation exposure (eg, neuroblastoma, median 133.5 mSv). For most diseases, surveillance imaging was not associated with increased overall survival, with the probable exception of Wilms tumor. No qualitative or psychological distress data were identified.

CONCLUSIONS

At present, there is insufficient evidence to evaluate the effects of routine surveillance imaging on survival in most pediatric extracranial solid tumors. More high-quality data are required, preferably through randomized controlled trials with well-conducted qualitative elements.

Is surveillance imaging in pediatric patients treated for localized rhabdomyosarcoma useful? The European experience

Background

After the completion of therapy, patients with localized rhabdomyosarcoma (RMS) are subjected to intensive radiological tumor surveillance. However, the clinical benefit of this surveillance is unclear. This study retrospectively analyzed the value of off‐therapy surveillance by comparing the survival of patients in whom relapse was detected by routine imaging (the imaging group) and patients in whom relapse was first suspected by symptoms (the symptom group).

Methods

This study included patients with relapsed RMS after the completion of therapy for localized RMS who were treated in large pediatric oncology hospitals in France, the United Kingdom, Italy, and the Netherlands and who were enrolled in the International Society of Paediatric Oncology Malignant Mesenchymal Tumor 95 (1995‐2004) study, the Italian Paediatric Soft Tissue Sarcoma Committee Rhabdomyosarcoma 96 (1996‐2004) study, or the European Paediatric Soft Tissue Sarcoma Study Group Rhabdomyosarcoma 2005 (2005‐2013) study. The survival times after relapse were compared with a log‐rank test between patients in the imaging group and patients in the symptom group.

Results

In total, 199 patients with relapsed RMS were included: 78 patients (39.2%) in the imaging group and 121 patients (60.8%) in the symptom group. The median follow‐up time after relapse was 7.4 years (interquartile range, 3.9‐11.5 years) for survivors (n = 86); the 3‐year postrelapse survival rate was 50% (95% confidence interval [CI], 38%‐61%) for the imaging group and 46% (95% CI, 37%‐55%) for the symptom group (P = .7).

Conclusions

Although systematic routine imaging is the standard of care after RMS therapy, the majority of relapses were detected as a result of clinical symptoms. This study found no survival advantage for patients whose relapse was detected before the emergence of clinical symptoms. These results show that the value of off‐therapy surveillance is controversial, particularly because repeated imaging may also entail potential harm.

This study assesses the clinical value of radiological surveillance imaging in pediatric patients with rhabdomyosarcoma, which is routinely performed after the completion of therapy. In the majority of patients, relapse is detected because of symptoms, and there is no evidence that early detection by imaging results in improved survival.

Surveillance imaging in pediatric lymphoma

Current therapies used in treating children with Hodgkin lymphoma and many histological subtypes of non-Hodgkin lymphoma have resulted in overall survival rates exceeding 90% in many instances. With increasing concerns related to the cost of radiologic imaging, exposure to ionizing radiation, and potential false-positive results, the role of routine off-therapy surveillance imaging has been called into question. Although radiologic imaging plays an important role in diagnosing and assessing treatment response, in these children - the majority of whom have an excellent outcome following completion of therapy - there is an opportunity to dramatically reduce the number of off-therapy imaging evaluations. This review summarizes several recent studies in both Hodgkin and non-Hodgkin lymphoma providing evidence to support these efforts. In addition, we propose a surveillance imaging strategy that uses a novel risk-adapted and response-based approach to determine which children would most benefit from off-therapy imaging surveillance.

Does routine surveillance imaging after completing treatment for childhood solid tumours cause more harm than good? A systematic review and meta-analysis protocol

BACKGROUND

This systemic review aims to synthesise the current literature surrounding off-therapy surveillance imaging in children and young people with extra-cranial solid tumours, with a view to establishing if routine imaging studies after treatment for childhood cancer increase overall survival, increase the psychological distress caused to patients and families, result in other harms to patients and are cost-effective strategies. Within this manuscript, we also describe how patient and public involvement has impacted upon the protocol.

METHODS

The search will cover thirteen different databases, key conference proceedings and trial registers, as well as reference lists and forward citations of included papers. Prominent authors/clinicians in the field will be contacted. A full search strategy is provided. The study designs to be included in the review will be added in an iterative way (RCTs, quasi-randomised trials, prospective cohorts and retrospective cohorts). Qualitative studies will also be eligible for inclusion. We will include studies which examine a programme of surveillance imaging that aims to detect relapse in children or young people up to age 25 years who have completed treatment for a malignant extracranial solid tumour and have no evidence of active and ongoing disease at end of treatment. The primary outcome is overall survival, with secondary outcomes including psychological distress indicators, number of imaging tests performed, other harms of imaging and cost-effectiveness measures. Studies will be screened and data extracted by two researchers. Studies will be critically appraised using a stratified version of the ROBINS-I tool. Where appropriate, data will be synthesised using a random effects meta-analysis. A detailed analysis plan, including assessment of heterogeneity and publication bias, is provided.

DISCUSSION

The aim of routine surveillance imaging is to detect recurrence of disease before clinical symptoms and signs develop. Some studies have suggested that most relapses of childhood cancer are detected due to clinical symptoms or signs, particularly in those with extra-cranial solid tumours, and when these relapses are detected by imaging, there is no increase in survival. This review aims to establish whether routine surveillance imaging is beneficial, as well as evaluating the potential negative impacts of surveillance programmes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018103764.

Impact of Surveillance Imaging Modality on Survival After Recurrence in Patients With Favorable-Histology Wilms Tumor: A Report From the Children's Oncology Group

PURPOSE

The use of computed tomography (CT) for routine surveillance to detect recurrence in patients with Wilms tumor (WT) has increased in recent years. The utility of CT, despite increased risk and cost, to improve outcome for these patients is unknown. We conducted a retrospective analysis with patients enrolled in the fifth National Wilms Tumor Study (NWTS-5) to determine if surveillance with CT correlates with improved overall survival (OS) after recurrence compared with chest x-ray (CXR) and abdominal ultrasound (US).

PATIENTS AND METHODS

Overall, 281 patients with recurrent unilateral favorable-histology WT were reviewed to assess how WT recurrence was detected: sign/symptoms (SS), surveillance imaging (SI) with CT scan, or SI with CXR/US.

RESULTS

The estimated 5-year OS rate after relapse was 67% (95% CI, 61% to 72%). Twenty-five percent of recurrences were detected with SS; 48.5%, with CXR/US; and 26.5%, with CT. Patients with SS had a 5-year OS rate of 59% (95% CI, 46% to 72%) compared with 70% (95% CI, 63% to 77%; P = .23) for those detected by SI. Recurrences detected by CT had a shorter median time from diagnosis to recurrence (0.60 years) compared with SS (0.91 years) or CXR/US (0.86 years; P = .003). For recurrences detected by SI, more tumor foci at relapse ( P < .001) and size of the largest focus greater than 2 cm ( P = .02) were associated with inferior OS. However, there was no difference in OS after relapse when recurrence was detected by CT versus CXR/US (5-year OS rate, 65% v 73%; P = .20).

CONCLUSION

In patients with favorable-histology WT, elimination of CT scans from surveillance programs is unlikely to compromise survival but would result in substantial reduction in radiation exposure and health care costs.

Relapse of Wilms' tumour and detection methods: a retrospective analysis of the 2001 Renal Tumour Study Group-International Society of Paediatric Oncology Wilms' tumour protocol database

BACKGROUND

Wilms' tumour is the most common renal cancer in childhood and about 15% of patients will relapse. There is scarce evidence about optimal surveillance schedules and methods for detection of tumour relapse after therapy.

METHODS

The Renal Tumour Study Group-International Society of Paediatric Oncology (RTSG-SIOP) Wilms' tumour 2001 trial and study is an international, multicentre, prospective registration, biological study with an embedded randomised clinical trial for children with renal tumours aged between 6 months and 18 years. The study covers 243 different centres in 27 countries grouped into five consortia. The current protocol of SIOP surveillance for Wilms' tumour recommends that abdominal ultrasound and chest x-ray should be done every 3 months for the first 2 years after treatment and be repeated every 4-6 months in the third and fourth year and annually in the fifth year. In this retrospective cohort study of the protocol database, we analysed data from participating institutions on timing, anatomical site, and mode of detection of all first relapses of Wilms' tumour. The primary outcomes were how relapse of Wilms' tumour was detected (ie, at or between scheduled surveillance and with or without clinical symptoms, scan modality, and physical examination) and to estimate the number of scans needed to capture one subclinical relapse. The RTSG-SIOP study is registered with Eudra-CT, number 2007-004591-39.

FINDINGS

Between June 26, 2001, and May 8, 2015, of 4271 eligible patients in the 2001 RTSG-SIOP Wilms' tumour database, 538 (13%) relapsed. Median follow-up from surgery was 62 months (IQR 32-93). The method used to detect relapse was registered for 410 (76%) of 538 relapses. Planned surveillance imaging captured 289 (70%) of these 410 relapses. The primary imaging modality used to detect relapse was reported for 251 patients, among which relapse was identified by abdominal ultrasound (80 [32%] patients), chest x-ray (78 [31%]), CT scan of the chest (64 [25%]) or abdomen (20 [8%]), and abdominal MRI (nine [4%]). 279 (68%) of 410 relapses were not detectable by physical examination and 261 (64%) patients did not have clinical symptoms at relapse. The estimated number of scans needed to detect one subclinical relapse during the first 2 years after nephrectomy was 112 (95% CI 106-119) and, for 2-5 years after nephrectomy, 500 (416-588).

INTERPRETATION

Planned surveillance imaging captured more than two-thirds of predominantly asymptomatic relapses of Wilms' tumours, with most detected by abdominal ultrasound, chest x-ray, or chest CT scan. Beyond 2 years post-nephrectomy, a substantial number of surveillance scans are needed to capture one relapse, which places a burden on families and health-care systems.

FUNDING

Great Ormond Street Hospital Children's Charity, the European Expert Paediatric Oncology Reference Network for Diagnostics and Treatment, The Danish Childhood Cancer Foundation, Cancer Research UK, the UK National Cancer Research Network and Children's Cancer and Leukaemia Group, Société Française des Cancers de l'Enfant and Association Leon Berard Enfant Cancéreux and Enfant et Santé, Gesellschaft für Pädiatrische Onkologie und Hämatologie and Deutsche Krebshilfe, Grupo Cooperativo Brasileiro para o Tratamento do Tumor de Wilms and Sociedade Brasileira de Oncologia Pediátrica, the Spanish Society of Pediatric Haematology and Oncology and the Spanish Association Against Cancer, and SIOP-Netherlands.

Ionizing radiation from computed tomography versus anesthesia for magnetic resonance imaging in infants and children: patient safety considerations

In the context of health care, risk assessment is the identification, evaluation and estimation of risk related to a particular clinical situation or intervention compared to accepted medical practice standards. The goal of risk assessment is to determine an acceptable level of risk for a given clinical treatment or intervention in association with the provided clinical circumstances for a patient or group of patients. In spite of the inherent challenges related to risk assessment in pediatric cross-sectional imaging, the potential risks of ionizing radiation and sedation/anesthesia in the pediatric population are thought to be quite small. Nevertheless both issues continue to be topics of discussion concerning risk and generate significant anxiety and concern for patients, parents and practicing pediatricians. Recent advances in CT technology allow for more rapid imaging with substantially lower radiation exposures, obviating the need for anesthesia for many indications and potentially mitigating concerns related to radiation exposure. In this review, we compare and contrast the potential risks of CT without anesthesia against the potential risks of MRI with anesthesia, and discuss the implications of this analysis on exam selection, providing specific examples related to neuroblastoma surveillance imaging.

Routine surveillance imaging after end of therapy for pediatric extracranial tumors: A retrospective analysis

Frequent surveillance imaging is routine practice for pediatric patients after cancer therapy. This retrospective study evaluated the follow-up of 301 children with extracranial tumors diagnosed between 2002 and 2012, at a tertiary pediatric cancer center in Beirut, Lebanon. Recurrence occurred in 15% of patients, at a median of 12 months after end of primary therapy. Outcome was not different comparing patients with recurrence detected via imaging surveillance versus clinically. False positive findings in 55 patients led to further interventions. These results raise important questions regarding benefit of current surveillance practices as standard care, especially in countries with limited resources.

[Relapse after rhabdomyosarcoma in childhood and adolescence: Impact of an early detection on survival]

SUBJECT

Prognostic values of an early detection of a relapse after treatment of a localized rhabdomyosarcoma and the interest of performing systematic radiologic assessment after treatment have not yet been evaluated in Europe.

MATERIAL AND METHODS

Modalities of relapse of 99 patients under 20 years of age, after an initially localized rhabdomyosarcoma, treated in 9 French centers ("Société française des cancers de l'enfant" consortium) have been analyzed. Prognostic value of the protocol compliance during the observation period after therapy has been evaluated.

RESULTS

Relapses have been diagnosed in 59 cases by a "symptom" the child was complaining of, in 12 cases because of "physical signs" detected during the clinical examination of a systematic consultation and in 27 cases thanks to "systematic follow-up imaging" (missing data: 1 case). Survival after relapse at 3 years was 47.5 % (IC95 %: 37.1 %-57.1 %). Diagnosis of the relapse is established earlier in the group "systematic imaging" rather than with other methods of detection ("symptom", "physical signs"), (P= 0.025), with detection of smaller tumors (≤ 5 cm ; 100.0 % vs. 60.9 % vs. 77.8 %, P= 0.007) but without possibility of reaching a second remission (70.4 % vs. 50.8 % vs. 50.0 % P= 0.37), nor significant impact on 5-year overall survival (47.1 % vs. 47.1 % vs. 48.6 % P= 0.94).

CONCLUSION

Current methods of systematic surveillance after a first-line treatment of an initially localized rhabdomyosarcoma seem to improve the earliness of the diagnosis, but not the prognosis of the relapse.

Accuracy of pre-contrast imaging in abdominal magnetic resonance imaging of pediatric oncology patients

BACKGROUND

Safety concerns are increasingly raised regarding the use of gadolinium-based contrast media for MR imaging.

OBJECTIVE

To determine the accuracy of pre-contrast abdominal MR imaging for lesion detection and characterization in pediatric oncology patients.

MATERIALS AND METHODS

We included 120 children (37 boys and 83 girls; mean age 8.94 years) referred by oncology services. Twenty-five had MRI for the first time and 95 were follow-up scans. Two authors independently reviewed pre-contrast MR images to note the following information about the lesions: location, number, solid vs. cystic and likely nature. Pre- and post-contrast imaging reviewed together served as the reference standard.

RESULTS

The overall sensitivity was 88% for the first reader and 90% for the second; specificity was 94% and 91%; positive predictive value was 96% and 94%; negative predictive value was 82% and 84%; accuracy of pre-contrast imaging for lesion detection as compared to the reference standard was 90% for both readers. The difference between mean number of lesions detected on pre-contrast imaging and reference standard was not significant for either reader (reader 1, P = 0.072; reader 2, P = 0.071). There was substantial agreement (kappa values of 0.76 and 0.72 for readers 1 and 2) between pre-contrast imaging and reference standard for determining solid vs. cystic lesion and likely nature of the lesion. The addition of post-contrast imaging increased confidence of both readers significantly (P < 0.0001), but the interobserver agreement for the change in confidence was poor (kappa 0.12).

CONCLUSION

Pre-contrast abdominal MR imaging has high accuracy in lesion detection in pediatric oncology patients and shows substantial agreement with the reference standard for characterization of lesions. Gadolinium-based contrast media administration cannot be completely eliminated but can be avoided in many cases, with the decision made on a case-by-case basis, taking into consideration location and type of tumor.

Surveillance imaging and radiation exposure in the detection of relapsed neuroblastoma

BACKGROUND

More than half of children with high-risk neuroblastoma (NB) will experience recurrence. Radiologic imaging is used for initial staging and during therapy to assess response. However, the role of surveillance imaging in the detection of relapse has not been well studied. Surveillance potentially results in high cumulative exposure to ionizing radiation, which may be associated with an increased risk of developing second malignancies.

PROCEDURE

We reviewed NB cases at our institution between 2000 and 2011. We calculated radiation exposure due to imaging (during diagnosis, treatment, and posttherapy surveillance) using cumulative effective dose (CED) estimates and determined whether cross-sectional imaging identified recurrences.

RESULTS

Fifty of 183 patients with NB experienced a recurrence. The median time from diagnosis to relapse was 1.20 years (range: 0.18-6.66 years). Most patients had evidence of metastases and only 4 of 50 patients presented with isolated primary tumor site recurrences. The mean CED prior to relapse was 125.2 mSv (range: 24.5-259.7), 64% of which was from computed tomography (CT) scans. Thirty-seven of 50 patients had clinically evident or measurable disease detected by X-ray (XR), ultrasound (US), or urinary catecholamines (UCats), and the addition of metaiodobenzylguanidine (MIBG) scans identified eight additional recurrences. Thus, cross-sectional imaging (CT/MRI, where MRI is magnetic resonance imaging) was only required to identify 10% (5/50) of cases.

CONCLUSION

Relapsed disease was detected in most patients by symptoms/exam, MIBG scan, UCats, and/or XR/US, supporting reduced use of CT imaging in posttherapy surveillance, thereby decreasing cumulative radiation dose. Refinement of surveillance imaging may be further guided by risk stratification, disease sites, and potentially biomolecular markers.

Does Routine Imaging of Patients for Progression or Relapse Improve Survival in Rhabdomyosarcoma?

BACKGROUND

Patients with rhabdomyosarcoma (RMS) who complete therapy typically undergo 4 years of surveillance imaging despite lack of evidence that this improves outcomes. We compared overall survival (OS) between patients in whom progression or relapse was detected by routine clinical evaluation or by imaging.

PROCEDURE

Children with progressive or relapsed RMS treated at Texas Children's Hospital between 1992 and 2012 were identified and their records were reviewed. Survival time after progression or relapse was compared between two groups: (1) patients in whom progression or relapse was suspected on the basis of clinical history, symptoms, laboratory evaluation, or physical exam; and (2) patients whose progression or relapse was initially detected by imaging.

RESULTS

Of the 43 children with progressive or relapsed RMS, 26 (60%) had metastatic disease at diagnosis and 19 (44%) had alveolar histology. With a median follow up time of 5 years in six survivors, there was no difference in OS between patients in whom progression or relapse was diagnosed based on imaging (n = 15) or by clinical evaluation (n = 28) (3-year OS 20% vs. 11%, respectively, P = 0.38). Disease extent, primary site, and risk group at diagnosis were associated with survival after progression or relapse.

CONCLUSIONS

Routine surveillance imaging practice should be critically reviewed for children with RMS. Although our findings must be validated by larger studies, they do have substantive implications. Reduced imaging tailored to the risk and pattern of recurrence, associated risks and cost could improve patient quality of life and decrease health-care expenditure without compromising outcome.

Post-treatment surveillance abdominopelvic computed tomography in children with Wilms tumour: Is it worth the risk?

Background: Wilms tumour is a comparatively common paediatric malignancy with a relatively good prognosis. Routine post-treatment surveillance at our institution currently includes regular abdominopelvic computed tomography (CT) over a two-year period for the early detection of disease recurrence. The rationale is that early salvage therapy may improve overall patient survival, and thus justifies the exposure to potentially harmful ionising radiation. Objective: To critically evaluate the routine use of post-treatment abdominopelvic CT by determining the detection rate of disease recurrence and associated clinical outcomes.Methods: Sixty-four patients in remission following initial treatment for Wilms tumour were included in this retrospective study. Variables obtained from patient records included gender, age, histological grading and tumour stage at presentation, number of abdominopelvic CT scans, site(s) of relapse, method of recurrence detection and confirmation, time to recurrence and clinical outcome. Results: The patients received a total of 334 surveillance abdominopelvic CT scans. Nine (14%) patients developed disease recurrence during the follow-up period. In three cases, the initial detection method was abdominopelvic CT. All three of these patients subsequently died despite salvage therapy (22 months median survival). Five false-positive diagnoses of recurrence occurred, with two being made on abdominopelvic CT. Conclusion: Routine post-treatment abdominopelvic CT showed a low detection rate of disease recurrence in children treated for Wilms tumour, while subjecting patients to a large radiation burden. The recommendation is that current practice be changed in line with the ultrasound-based Société Internationale d’Oncologie Pédiatrique (SIOP) imaging guidelines.

CT scanning in children and risk of cancer: what three large-scale studies have demonstrated

That irradiation from diagnostic CT examinations has caused cancers in a small minority of young patients in the past is no longer controversial. Three recent studies from the UK, Australia and the USA have published data supporting a small but real risk of a CT scan in early life being associated with a later risk of malignancy, due solely to the CT scan. The American study showed a temporary increase in the frequency of CT scanning of children with regrettably large variation in radiation dose per scan. Most of the patients in the published studies had their CT examinations over a decade ago, and it is likely in more recent years that widespread reductions in tube current-time product (mAs) have substantially lessened the radiation burden to children from CT. It must be remembered that CT is a very useful clinical test. Whenever CT is justified, the clinical benefit virtually always outweighs the longer term very small risk of malignancy.

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.