Assessment of referrals into the soft tissue sarcoma service: evaluation of imaging early in the pathway process

Soft tissue tumor imaging in adults: European Society of Musculoskeletal Radiology-Guidelines 2023-overview, and primary local imaging: how and where?

OBJECTIVES

Early, accurate diagnosis is crucial for the prognosis of patients with soft tissue sarcomas. To this end, standardization of imaging algorithms, technical requirements, and reporting is therefore a prerequisite. Since the first European Society of Musculoskeletal Radiology (ESSR) consensus in 2015, technical achievements, further insights into specific entities, and the revised WHO-classification (2020) and AJCC staging system (2017) made an update necessary. The guidelines are intended to support radiologists in their decision-making and contribute to interdisciplinary tumor board discussions.

MATERIALS AND METHODS

A validated Delphi method based on peer-reviewed literature was used to derive consensus among a panel of 46 specialized musculoskeletal radiologists from 12 European countries. Statements were scored online by level of agreement (0 to 10) during two iterative rounds. Either "group consensus," "group agreement," or "lack of agreement" was achieved.

RESULTS

Eight sections were defined that finally contained 145 statements with comments. Overall, group consensus was reached in 95.9%, and group agreement in 4.1%. This communication contains the first part consisting of the imaging algorithm for suspected soft tissue tumors, methods for local imaging, and the role of tumor centers.

CONCLUSION

Ultrasound represents the initial triage imaging modality for accessible and small tumors. MRI is the modality of choice for the characterization and local staging of most soft tissue tumors. CT is indicated in special situations. In suspicious or likely malignant tumors, a specialist tumor center should be contacted for referral or teleradiologic second opinion. This should be done before performing a biopsy, without exception.

CLINICAL RELEVANCE

The updated ESSR soft tissue tumor imaging guidelines aim to provide best practice expert consensus for standardized imaging, to support radiologists in their decision-making, and to improve examination comparability both in individual patients and in future studies on individualized strategies.

KEY POINTS

• Ultrasound remains the best initial triage imaging modality for accessible and small suspected soft tissue tumors. • MRI is the modality of choice for the characterization and local staging of soft tissue tumors in most cases; CT is indicated in special situations. Suspicious or likely malignant tumors should undergo biopsy. • In patients with large, indeterminate or suspicious tumors, a tumor reference center should be contacted for referral or teleradiologic second opinion; this must be done before a biopsy.

Predicting the malignancy of extremity soft-tissue tumors by an ultrasound-based radiomics signature

BACKGROUND

Accurate differentiation of extremity soft-tissue tumors (ESTTs) is important for treatment planning.

PURPOSE

To develop and validate an ultrasound (US) image-based radiomics signature to predict ESTTs malignancy.

MATERIAL AND METHODS

A dataset of US images from 108 ESTTs were retrospectively enrolled and divided into the training cohort (78 ESTTs) and validation cohort (30 ESTTs). A total of 1037 radiomics features were extracted from each US image. The most useful predictive radiomics features were selected by the maximum relevance and minimum redundancy method, least absolute shrinkage, and selection operator algorithm in the training cohort. A US-based radiomics signature was built based on these selected radiomics features. In addition, a conventional radiologic model based on the US features from the interpretation of two experienced radiologists was developed by a multivariate logistic regression algorithm. The diagnostic performances of the selected radiomics features, the US-based radiomics signature, and the conventional radiologic model for differentiating ESTTs were evaluated and compared in the validation cohort.

RESULTS

In the validation cohort, the area under the curve (AUC), sensitivity, and specificity of the US-based radiomics signature for predicting ESTTs malignancy were 0.866, 84.2%, and 81.8%, respectively. The US-based radiomics signature had better diagnostic predictability for predicting ESTT malignancy than the best single radiomics feature and the conventional radiologic model (AUC = 0.866 vs. 0.719 vs. 0.681 for the validation cohort, all P <0.05).

CONCLUSION

The US-based radiomics signature could provide a potential imaging biomarker to accurately predict ESTT malignancy.

Imaging Recommendations for Diagnosis, Staging, and Management of Soft Tissue Sarcomas

Soft tissue lesions are a wide range of tumors of mesenchymal cell origin, occurring anywhere in the body with a vast number of histological subtypes both benign and malignant. These are common in clinical practice and vast majority are benign. This article focuses on soft tissue sarcoma of the trunk and extremities and discusses their imaging guidelines.

Ultrasound of myxofibrosarcoma

The ultrasound appearance of myxofibrosarcoma is highly variable corresponding to its variable and at times heterogeneous histopathologic appearance. Myxofibrosarcomas may mimic a benign process and the infiltrative tumor margins may be difficult to precisely delineate on ultrasound imaging. These tumor characteristics pose a diagnostic challenge on ultrasound evaluation. The radiologist should be aware of the variable morphologic presentation and infiltrative nature of myxofibrosarcoma and the limitations of ultrasound in the initial diagnosis, biopsy guidance, and post-surgical follow-up of this tumor.

Biopsy Ratio of Suspected to Confirmed Sarcoma Diagnosis

Simple Summary

Determining the biology of mesenchymal tumor, imaging alone is usually not enough, and the final diagnosis is established through tissue analysis If the indication to perform a biopsy is not established frequently enough, an undesired unplanned resection of a sarcoma may result, and conversely, a patient’s discomfort as well as costs may increase. In here, using a real-world data registry of quality, we included the absolute number of a consecutive series of patients, to determine the prevalence of biopsies and its related diagnosis, to establish a reference, which may allow for the definition of a quality indicator for the work-up within a multidisciplinary team.

Abstract

The ratio of malignancy in suspicious soft tissue and bone neoplasms (RMST) has not been often addressed in the literature. However, this value is important to understand whether biopsies are performed too often, or not often enough, and may therefore serve as a quality indicator of work-up for a multidisciplinary team (MDT). A prerequisite for the RMST of an MDT is the assessment of absolute real-world data to avoid bias and to allow comparison among other MDTs. Analyzing 950 consecutive biopsies for sarcoma-suspected lesions over a 3.2-year period, 55% sarcomas were confirmed; 28% turned out to be benign mesenchymal tumors, and 17% non-mesenchymal tumors, respectively. Of these, 3.5% were metastases from other solid malignancies, 1.5% hematologic tumors and 13% sarcoma simulators, which most often were degenerative or inflammatory processes. The RMST for biopsied lipomatous lesions was 39%. The ratio of unplanned resections was 10% in this series. Reorganizing sarcoma work-up into integrating practice units (IPU) allows the assessment of real-world data with absolute values over the geography, thereby enabling the definition of quality indicators and addressing cost efficiency aspects of sarcoma care.

Small soft tissue masses indeterminate at imaging: histological diagnoses at a tertiary orthopedic oncology clinic

OBJECTIVE

To review histologic diagnoses of soft-tissue masses (STMs) ≤ 2 cm with indeterminate imaging features encountered in musculoskeletal oncology clinic at a tertiary referral center.

MATERIALS AND METHODS

This was an IRB-approved retrospective review of patients with STMs ≤ 2 cm, referred to our tertiary care orthopedic oncology clinic over 4.75 consecutive years. Maximum diameter was based on imaging measurement by a fellowship-trained musculoskeletal radiologist. Simple lipomas, synovial cysts, metastases, and cases without histologic confirmation were excluded. Patient demographics, tumor imaging features (location, depth, size, and tumor:muscle enhancement and T2 signal ratios), and histology were recorded and compared.

RESULTS

Mean maximum diameter for 42 trunk/extremity STMs was 1.5 cm (range, 0.7 to 2 cm). Mean age was 48 years (range, 18-83 years). Nine (21%) of the masses were malignant, while 33 (79%) were non-malignant. Thirty-nine (93%) of masses were superficial; 7/39 (18%) of these superficial tumors were malignant. Malignancy was not associated with underlying vessels, tendon, or fascia (p = 0.19). The non-malignant vs. malignant tumor:muscle enhancement ratio was 2.15 vs. 2.32 (p = 0.58) and enhancement coefficient of variation was 0.14 vs. 0.10 (p = 0.29). Most common malignant histologic subtypes were synovial sarcoma (n = 3), fibroblastic/myofibroblastic sarcoma (n = 2), leiomyosarcoma (n = 2), myxofibrosarcoma (n = 1), and angiomatoid fibrous histiocytoma (n = 1). The majority (67%) of non-malignant lesions were: leiomyoma (n = 6), angiomyoma (n = 5), schwannoma (n = 4), benign fibrous histiocytoma (n = 4), and hemangioma (n = 3).

CONCLUSIONS

At a tertiary musculoskeletal oncology referral clinic, primary STMs ≤ 2 cm with indeterminate imaging features should be managed cautiously despite their small size and/or superficial location.

Diagnostic performance of MRI and histology in assessment of deep lipomatous tumours

BACKGROUND

Deep lipomatous tumours can be benign lipomas or intermediate/locally recurring atypical lipomatous tumours (ALTs). Differentiating between these two entities clinically and radiologically is difficult. The aims of this study were to report a series of deep lipomatous tumours, comparing the clinical, radiological and pathological features of ALTs and lipomas; and to predict the likelihood of a lipomatous tumour being ALT based on anatomical site and MRI characteristics.

METHODS

This was a retrospective review of patients with deep lipomatous tumours presenting over 6 years to a tertiary sarcoma centre, with preoperative MRI, and preoperative or postoperative histology including MDM2 gene analysis. Sensitivity, specificity, predictive values and accuracy in diagnosing ALT were calculated for MRI and histopathological features.

RESULTS

Some 248 patients were included; 81 (32·7 per cent) had a final diagnosis of ALT. ALTs were larger than lipomas (median 19 versus 10 cm; P < 0·001); there was no ALT smaller than 5 cm. A tumour presenting in the lower limb was more likely to be an ALT than a lesion at any other site (48·4 versus 13·5 per cent; P < 0·001). In patients with lipomatous tumours at sites other than the lower limbs, MRI had a negative predictive value of 95 per cent for excluding ALT.

CONCLUSION

Despite concern, most deep lipomatous tumours (nearly 70 per cent) are benign lipomas. Certain features imply that tumours are almost never ALT: smaller than 5 cm or located outside the lower limb with no suspicious characteristics on MRI. Tumours with these features might safely and confidently be managed outside tertiary sarcoma centres.

Imaging investigations before referral to a sarcoma center delay the final diagnosis of musculoskeletal sarcoma

Background and purpose - The use of point-of-care or local investigations before referral to specialist sarcoma centers as part of a fast-track diagnostic pathway varies, and may affect the time to diagnosis. We wanted to investigate differences in time intervals and proportion of malignancy in patients who were referred after initial diagnostic investigations were performed locally and in patients who were referred without these investigations. Patients and methods - We included 545 consecutive patients who were referred to Aarhus Sarcoma Center for suspected musculoskeletal sarcoma. Data on time intervals and investigations performed were collected from questionnaires and patient records. Patients who were referred from outside Aarhus uptake area after initial MRI/CT or histology performed locally were compared with patients who were referred from Aarhus uptake area without these investigations. Results - The median total interval from first symptom to diagnosis was 166 days for outside patients referred with MRI/CT or histology, which was 91 (95% CI: 76-106) days longer than for local patients who were referred without MRI/CT or histology. Comparing the same groups, the median diagnostic interval was 41 (95% CI: 30-51) days longer for outside patients including both primary care and hospital intervals. Both the proportion of malignancies (38% vs. 14%) and the proportion of sarcomas (24% vs. 7%) were higher in the outside group referred with MRI/CT or histology than in the local group without MRI/CT or histology. Interpretation - Pre-referral investigations at a local hospital increased the diagnostic interval by at least 1 month for 50% of the patients, and the proportion of malignancy was more than doubled-to almost 40%. If investigations are to be performed before referral to a sarcoma center, they should be part of the fast-track pathway in order to ensure timely diagnosis.

A Comprehensive Single Institutional Review of 2 Years in a Designated Fast-Track Sarcoma Diagnostic Clinic Linked with a Sarcoma Specialist Advisory Group: Meeting the Target but Failing the Task?

Background. National guidelines prompted the implementation of a designated two-week wait referral pathway to facilitate the early diagnosis of sarcomas, to improve treatment outcomes. Methods. Patients referred to the Cambridge Sarcoma Diagnostic Clinic between January 2013 and December 2014 were identified through the electronic appointments system. Information was retrospectively retrieved about patient characteristics and details of the diagnostic pathway. Results. 17.3% of patients referred (69/397) were diagnosed with a malignancy. Of these, 59.3% (41/69) had primary sarcomas, 17.4% (12/69) had metastatic cancer, and 23.2% (16/69) had a different primary malignancy. 15% of the 41 sarcomas were <5 cm, 34% in the 5-10 cm range, and 51% >10 cm. Sarcomas diagnosed through this clinic represented 13% (41/315) of sarcomas managed at the centre during the same 2 years. Conclusion. While we achieved the target of 10% (41/397) sarcoma diagnosis rate in the rapid access clinic, only 15% of these were <5 cm better prognosis lesions. This calls into question the "real world" impact of such diagnostic clinics on early diagnosis of sarcomas. In order to enhance generic cancer diagnostic skills, training in these diagnostic clinics could be usefully integrated into national training curricula for both surgical and nonsurgical oncologists.

If your lump is bigger than a golf ball and growing, think Sarcoma

AIM

Only 1 in 100 of primary care consultations regarding new soft tissue lumps (STL) are malignant and are susceptible to a delay in diagnosis. We aimed to generate a Bayesian Belief Network to estimate the likelihood of malignancy in patients to facilitate the initial evaluation of a STL and improve timing and quality of referrals to specialist treatment centres.

METHODS

We evaluated all patients referred with a new STL between 1996 and 2007. Variables investigated focused on patient factors, symptoms and STL characteristics. Relevant data was extracted and coded for statistical analysis.

RESULTS

3018 patients with a STL were assessed, of which 1563 (52%) were benign and 1455 (48%) malignant. The features most conditionally associated with the outcome of interest (Benign or Malignant) are referred to as first-degree associates, and are increasing size, age, size of the lump, and duration of symptoms, in that order. On cross validation, this model demonstrated an AUC of 0.77 (95%C.I. 0.75-0.79).

CONCLUSIONS

For the first time, we have described the hierarchal relationship between factors and created an aide memoire, larger than a golf ball and growing, to trigger referral to tertiary tumor units. Importantly, we found pain to be a poor discriminatory factor. We hope our findings will lead to greater awareness and earlier diagnosis of STL.

Diagnostic triage for sarcoma: an effective model for reducing referrals to the sarcoma multidisciplinary team

OBJECTIVE

Soft-tissue lesions are common and often benign. Owing to the rarity of soft-tissue sarcomas (STSs), evidence has shown that patients are increasingly referred urgently onto the 2-week wait pathway, which may have a detrimental impact on the management of patients with a proven STS. Imaging plays a vital role in lesion characterization and can be used to triage referrals to reduce the caseload of a sarcoma multidisciplinary team (MDT). In our institution, we established a sarcoma diagnostic triage meeting (SDTM). This study aimed to determine the effectiveness of the SDTM in reducing non-sarcomatous referrals to the main sarcoma MDT.

METHODS

A retrospective review of the SDTM minutes from July 2011 to June 2012 was performed. Data collected for each case included details of referrer, referral modality and referral outcome.

RESULTS

165 cases were reviewed. 58% of referrals underwent a core biopsy or surgical excision with 85% benign pathology, the commonest being lipoma. 15% of referrals were sarcomatous lesions and were referred onwards to the main MDT.

CONCLUSION

A total of 82% of the patients referred urgently with a suspicious soft-tissue mass was managed by the SDTM and hence not referred onwards to the East Midlands Sarcoma Service MDT. A diagnostic triage is effective in reducing the caseload burden of the main MDT and allowing it to be more effective.

ADVANCES IN KNOWLEDGE

Referrals based on imaging can be prioritized by diagnostic triage. Diagnostic triage established in our institution reduced 82% of MDT referrals allowing a more focused MDT discussion on patients with a proven sarcoma.

[Health care circuit for patients with soft tissue sarcomas of the extremities. A tortuous and slow road to referral units]

OBJECTIVE

To analyse the waiting periods elapsed since soft tissue sarcomas become symptomatic until their specific treatment in our unit, and to determine new strategies for the improvement of referral circuits.

MATERIAL AND METHODS

This is an ambispective observational study of a cohort of 61 patients, with previously untreated soft tissue sarcomas, obtained from our Musculoskeletal Tumors Database. Several variables related to the patient, tumour, and health care circuit were analysed, as well as the different periods between the initial symptoms of the disease and the first consultation in our unit. The significance level was α=0.05.

RESULTS

The mean size of the sarcomas was 11.3 cm. Thirty-six patients (59%) followed the usual circuit of the National Health System in Spain. The time elapsed since the disease became symptomatic until the first medical consultation was greater than 9.5 months, and nearly another 8.5 months to the consultation in our specific unit. Statistically significant relationships were found between the independent and dependent variables.

DISCUSSION

The study shows that the care of patients with soft tissue sarcomas in our environment is far away from the times of care in our neighbouring countries.

CONCLUSIONS

It is essential to make the population and health professionals aware of this disease, as well as to remember that there is a referral circuit that must be used.

[Intramuscular lipomas: Large and deep benign lumps not to underestimated. Review of a series of 51 cases]

OBJECTIVE

To review a poorly studied pathology in the scientific literature.

MATERIAL AND METHODS

An observational, longitudinal and ambispective study of a series of 51 intramuscular lipomas in 50 patients. The frequency distribution of qualitative variables, and the median and the interquartile range (IQR) for continuous variables were calculated. The relationship between the size of the lipomas (recoded into two values) and the study variables were analyzed using the Fisher exact test.

RESULTS

Men made up 62% of the series, and the median age was 61 years, with 55% of the total being overweight. About half of the patients were diagnosed in the upper limb. More than three-quarters (78%) were strictly intramuscular lipomas. Location, clinical and image presentation, treatment and results are described.

DISCUSSION

Intramuscular lipomas have their own particular characteristics. Nevertheless, MRI is sometimes unable to distinguish them from well differentiated liposarcomas. Using size as the only criterion for referring a patient with a soft tissue injury to a reference center is still debatable.

CONCLUSIONS

Patients with intramuscular lipomas, although they may be typical in their presentation, especially when they are large and show findings that can be confused with a well-differentiated low grade liposarcoma, should be treated in experienced centers.