Imaging in rhabdomyosarcoma: a patient journey

Rhabdomyosarcoma, although rare, is the most frequent soft tissue sarcoma in children and adolescents. It can present as a mass at nearly any site in the body, with most common presentations in the head and neck, genitourinary tract and extremities. The optimal diagnostic approach and management of rhabdomyosarcoma require a multidisciplinary team with multimodal treatment, including chemotherapy and local therapy. Survival has improved over the last decades; however, further improvement in management is essential with current 5-year overall survival ranging from 35% to 100%, depending on disease and patient characteristics. In the full patient journey, from diagnosis, staging, management to follow-up after therapy, the paediatric radiologist and nuclear physician are essential members of the multidisciplinary team. Recently, guidelines of the European paediatric Soft tissue sarcoma Study Group, the Cooperative Weichteilsarkom Studiengruppe and the Oncology Task Force of the European Society of Paediatric Radiology (ESPR), in an ongoing collaboration with the International Soft-Tissue Sarcoma Database Consortium, provided guidance for high-quality imaging. In this educational paper, given as a lecture during the 2022 postgraduate ESPR course, the multi-disciplinary team of our national paediatric oncology centre presents the journey of two patients with rhabdomyosarcoma and discusses the impact on and considerations for the clinical (paediatric) radiologist and nuclear physician. The key learning points of the guidelines and their implementation in clinical practice are highlighted and up-to-date insights provided for all aspects from clinical suspicion of rhabdomyosarcoma and its differential diagnosis, to biopsy, staging, risk stratification, treatment response assessment and follow-up.

Using Evidence-Based Medicine to Support Clinical Decision-Making in RMS

The foundations of evidence-based practice are the triad of patient values and preferences, healthcare professional experience, and best available evidence, used together to inform clinical decision-making. Within the field of rhabdomyosarcoma, collaborative groups such as the European Paediatric Soft Tissue Sarcoma Group (EpSSG) have worked to develop evidence to support this process. We have explored many of the key research developments within this review, including patient and public involvement, decision-making research, research into areas other than drug development, core outcome sets, reporting and dissemination of research, evidence synthesis, guideline development and clinical decision rules, research of research methodologies, and supporting research in RMS.

[Follow-up imaging in children with rhabdomyosarcoma: less scans, the same yield]

Children treated for rhabdomyosarcoma are subject to protocolized follow-up imaging to detect a potential relapse earlier and to improve the chances of survival in case of a relapse. In this study we report on our findings concerning the clinical value of radiologic imaging in patients with rhabdomyosarcoma. We showed that the majority of relapses were detected by clinical symptoms, despite the frequent imaging. These results were used to define a new follow-up recommendation that was successfully implemented in the current European paediatric Soft tissue sarcoma Study Group guideline. In this new recommendation we reduced the number of radiologic imaging examinations performed after end-of-therapy by 50%, and decreased the follow-up time after end-of-therapy to 2 years.

Fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT) for the detection of bone, lung, and lymph node metastases in rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common paediatric soft-tissue sarcoma and can emerge throughout the whole body. For patients with newly diagnosed RMS, prognosis for survival depends on multiple factors such as histology, tumour site, and extent of the disease. Patients with metastatic disease at diagnosis have impaired prognosis compared to those with localised disease. Appropriate staging at diagnosis therefore plays an important role in choosing the right treatment regimen for an individual patient. Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is a functional molecular imaging technique that uses the increased glycolysis of cancer cells to visualise both structural information and metabolic activity. 18F-FDG-PET combined with computed tomography (CT) could help to accurately stage the extent of disease in patients with newly diagnosed RMS. In this review we aimed to evaluate whether 18F-FDG-PET could replace other imaging modalities for the staging of distant metastases in RMS.

OBJECTIVES

To determine the diagnostic accuracy of 18F-FDG-PET/CT imaging for the detection of bone, lung, and lymph node metastases in RMS patients at first diagnosis.

SEARCH METHODS

We searched MEDLINE in PubMed (from 1966 to 23 December 2020) and Embase in Ovid (from 1980 to 23 December 2020) for potentially relevant studies. We also checked the reference lists of relevant studies and review articles; scanned conference proceedings; and contacted the authors of included studies and other experts in the field of RMS for information about any ongoing or unpublished studies. We did not impose any language restrictions.

SELECTION CRITERIA

We included cross-sectional studies involving patients with newly diagnosed proven RMS, either prospective or retrospective, if they reported the diagnostic accuracy of 18F-FDG-PET/CT in diagnosing lymph node involvement or bone metastases or lung metastases or a combination of these metastases. We included studies that compared the results of the 18F-FDG-PET/CT imaging with those of histology or with evaluation by a multidisciplinary tumour board as reference standard.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, and methodological quality assessement according to Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). We analysed data for the three outcomes (nodal involvement and lung and bone metastases) separately. We used data from the 2 × 2 tables (consisting of true positives, false positives, true negatives, and false negatives) to calculate sensitivity and specificity in each study and corresponding 95% confidence intervals. We did not consider a formal meta-analysis to be relevant because of the small number of studies and substantial heterogeneity between studies.

MAIN RESULTS

Two studies met our inclusion criteria. The diagnostic accuracy of 18F-FDG-PET/CT was reported in both studies, which included a total of 36 participants. We considered both studies to be at high risk of bias for the domain reference standard. We considered one study to be at high risk of bias for the domain index test and flow and timing. Sensitivity and specificity of 18F-FDG-PET/CT for the detection of bone metastases was 100% in both studies (95% confidence interval (CI) for sensitivity was 29% to 100% in study one and 40% to 100% in study two; 95% CI for specificity was 83% to 100% in study one and 66% to 100% in study two). The reported sensitivity of 18F-FDG-PET/CT for the detection of lung metastases was not calculated since only two participants in study two showed lung metastases, of which one was detected by 18F-FDG-PET/CT. Reported specificity was 96% in study one (95% CI 78% to 100%) and 100% (95% CI 72% to 100%) in study two. The reported sensitivity for the detection of nodal involvement was 100% (95% CI 63% to 100% in study one and 40% to 100% in study two); the reported specificity was 100% (95% CI 78% to 100%) in study one and 89% (95% CI 52% to 100%) in study two.

AUTHORS' CONCLUSIONS

The diagnostic accuracy of 18F-FDG-PET/CT for the detection of bone, lung, and lymph node metastases was reported in only two studies including a total of only 36 participants with newly diagnosed RMS. Because of the small number of studies (and participants), there is currently insufficient evidence to reliably determine the diagnostic accuracy of 18F-FDG-PET/CT in the detection of distant metastases. Larger series evaluating the diagnostic accuracy of 18F-FDG-PET/CT for the detection of metastases in patients with RMS are necessary.

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.

Indeterminate Pulmonary Nodules at Diagnosis in Rhabdomyosarcoma: Are They Clinically Significant? A Report From the European Paediatric Soft Tissue Sarcoma Study Group

Purpose

To evaluate the clinical significance of indeterminate pulmonary nodules at diagnosis (defined as ≤ 4 pulmonary nodules < 5 mm or 1 nodule measuring ≥ 5 and < 10 mm) in patients with pediatric rhabdomyosarcoma (RMS).

Patients and Methods

We selected patients with supposed nonmetastatic RMS treated in large pediatric oncology centers in the United Kingdom, France, Italy, and the Netherlands, who were enrolled in the European Soft Tissue Sarcoma Study Group (E pSSG) RMS 2005 study. Patients included in the current study received a diagnosis between September 2005 and December 2013, and had chest computed tomography scans available for review that were done at time of diagnosis. Local radiologists were asked to review the chest computed tomography scans for the presence of pulmonary nodules and to record their findings on a standardized case report form. In the E pSSG RMS 2005 Study, patients with indeterminate pulmonary nodules were treated identically to patients without pulmonary nodules, enabling us to compare event-free survival and overall survival between groups by log-rank test.

Results

In total, 316 patients were included; 67 patients (21.2%) had indeterminate pulmonary nodules on imaging and 249 patients (78.8%) had no pulmonary nodules evident at diagnosis. Median follow-up for survivors (n = 258) was 75.1 months; respective 5-year event-free survival and overall survival rates (95% CI) were 77.0% (64.8% to 85.5%) and 82.0% (69.7% to 89.6%) for patients with indeterminate nodules and 73.2% (67.1% to 78.3%) and 80.8% (75.1% to 85.3%) for patients without nodules at diagnosis ( P = .68 and .76, respectively).

Conclusion

Our study demonstrated that indeterminate pulmonary nodules at diagnosis do not affect outcome in patients with otherwise localized RMS. There is no need to biopsy or upstage patients with RMS who have indeterminate pulmonary nodules at diagnosis.

Getting control during follow-up visits: the views and experiences of parents on tumor surveillance after their children have completed therapy for rhabdomyosarcoma or Ewing sarcoma

Purpose

Patients treated for rhabdomyosarcoma (RMS) or Ewing sarcoma (ES) are subject to extensive follow-up after completion of therapy. The aim of this follow-up is to monitor treatment side effects and to detect relapse in an early phase to improve prognosis after relapse. Little is known about parental emotional experiences during this period. We assessed the views and experiences of parents of children treated for RMS or ES on the follow-up examinations after completion of therapy.

Methods

We conducted two focus group meetings and four semi-structured telephone interviews with parents of children treated for RMS or ES in Dutch pediatric oncology centers. Parents of children 0–5 years after end-of-therapy were invited via letters (response rate 31%) and via social media channels of “Dutch Childhood Association for Children and Parents” (VOKK). An inductive thematic approach was used to analyze the data.

Results

In total, 12 parents (fathers, n = 3; mothers, n = 9) of 12 patients treated for RMS (n = 6) or ES (n = 6) participated. Median age at diagnosis for their children was 7.9 years and median time after end-of-treatment was 37 months. Four major themes were identified: content of follow-up, distress and anxiety, search for reassurance and hope, and interaction with others. Parents of children treated for RMS or ES report experiencing significant distress after completion of treatment. They report that their distress was decreased by adequate communication about content, timing, and reasoning behind follow-up.

Conclusion

Physicians should pay attention to the needs of individual parents to reduce distress in the period after completion of therapy.

Psychosocial well-being of long-term survivors of pediatric head-neck rhabdomyosarcoma

BACKGROUND

Head and neck rhabdomyosarcoma (HNRMS) survivors are at risk to develop adverse events (AEs). The impact of these AEs on psychosocial well-being is unclear. We aimed to assess psychosocial well-being of HNRMS survivors and examine whether psychosocial outcomes were associated with burden of therapy.

PROCEDURE

Sixty-five HNRMS survivors (median follow-up: 11.5 years), treated in the Netherlands and the United Kingdom between 1990 and 2010 and alive ≥2 years after treatment visited the outpatient multidisciplinary follow-up clinic once, in which AEs were scored based on a predefined list according to the Common Terminology Criteria for Adverse Events. Survivors were asked to complete questionnaires on health-related quality of life (HRQoL; PedsQL and YQOL-FD), self-perception (KIDSCREEN), and satisfaction with appearances (SWA). HRQoL and self-perception scores were compared with reference values, and the correlation between physician-assessed AEs and psychosocial well-being was assessed.

RESULTS

HNRMS survivors showed significantly lower scores on PedsQL school/work domain (P ≤ 0.01, P = 0.02, respectively), YQOL-FD domains negative self-image and positive consequences (P ≤ 0.01, P = 0.04, respectively) compared with norm data; scores on negative consequences domain were significantly higher (P = 0.03). Over 50% of survivors negatively rated their appearances on three or more items. Burden of AEs was not associated with generic HRQoL and self-perception scores, but was associated with disease-specific QoL (YQOL-FD).

CONCLUSION

In general, HRQoL in HNRMS survivors was comparable to reference groups; however, survivors did report disease-specific consequences. We therefore recommend including specific questionnaires related to difficulties with facial appearance in a systematic monitoring program to determine the necessity for tailored care.

AMORE treatment as salvage treatment in children and young adults with relapsed head-neck rhabdomyosarcoma

BACKGROUND AND PURPOSE

Survival after relapse of head and neck rhabdomyosarcoma (HNRMS) after prior external beam radiotherapy (EBRT) is poor, since options for adequate local treatment are often lacking. In this study we describe our experience with salvage AMORE in patients with relapsed HNRMS after prior EBRT.

MATERIALS AND METHODS

Patients with relapsed HNRMS after prior EBRT in which salvage AMORE treatment was considered feasible were analysed; this includes patients with parameningeal, head and neck non-parameningeal and orbital localization. AMORE treatment consisted of Ablative surgery, MOuld technique brachytherapy and surgical REconstruction.

RESULTS

In total 18 patients received salvage AMORE treatment; nine patients had relapsed parameningeal (PM) RMS, two patients had relapsed head and neck non-parameningeal RMS (HN-nonPM) and seven patients had relapsed orbital RMS. Local control rate was 67% and 5-year overall survival was 54% (95% confidence interval: 31-78%); 3/9 patients with PM RMS, 0/2 patients with HN-nonPM RMS and 6/7 patients with orbital RMS were alive after a median follow-up of 8.6 years. One patient with PM RMS survived more than 5 years after which he died from a secondary cancer. Six patients developed a local relapse (of which one patient also developed a distant metastasis) and two patients developed distant metastases.

CONCLUSIONS

Salvage AMORE treatment is a feasible and effective local therapy approach even after prior EBRT. Since salvage AMORE treatment is sometimes the only curative option in patient with relapsed HNRMS, we encourage physicians to consider salvage AMORE treatment for patients with relapsed HNRMS after prior EBRT.