UK guidelines for the management of soft tissue sarcomas

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location, means that developing evidence-based guidelines is complicated by the limitations of the data available. This makes it more important that STS are managed by expert multidisciplinary teams, to ensure consistent and optimal treatment, recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous versions published in 2010 and 2016 [1, 2]. The original guidelines were drawn up by a panel of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This iteration of the guidance, as well as updating the general multidisciplinary management of soft tissue sarcoma, includes specific sections relating to the management of sarcomas at defined anatomical sites: gynaecological sarcomas, retroperitoneal sarcomas, breast sarcomas, and skin sarcomas. These are generally managed collaboratively by site specific multidisciplinary teams linked to the regional sarcoma specialist team, as stipulated in the recently published sarcoma service specification [3]. In the UK, any patient with a suspected soft tissue sarcoma should be referred to a specialist regional soft tissues sarcoma service, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging and a tissue biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon, combined with pre- or post-operative radiotherapy for tumours at higher risk for local recurrence. Systemic anti-cancer therapy (SACT) may be utilised in cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late effects of treatment.

New Sarculator Prognostic Nomograms for Patients With Primary Retroperitoneal Sarcoma: Case Volume Does Matter

OBJECTIVE

To update the current Sarculator retroperitoneal sarcoma (RPS) prognostic nomograms considering the improvement in patient prognosis and the case volume effect.

BACKGROUND

Survival of patients with primary RPS has been increasing over time, and the volume-outcome relationship has been well recognized. Nevertheless, the specific impact on prognostic nomograms is unknown.

METHODS

All consecutive adult patients with primary localized RPS treated at 8 European and North American sarcoma reference centers between 2010 and 2017 were included. Patients were divided into 2 groups: high-volume centers (HVC, ≥13 cases/year) and low-volume centers (LVC, <13 cases/year). Primary end points were overall survival (OS) and disease-free survival (DFS). Multivariable analyses for OS and DFS were performed. The nomograms were updated by recalibration. Nomograms performance was assessed in terms of discrimination (Harrell C index) and calibration (calibration plot).

RESULTS

The HVC and LVC groups comprised 857 and 244 patients, respectively. The median annual primary RPS case volume (interquartile range) was 24.0 in HVC (15.0-41.3) and 9.0 in LVC (1.8-10.3). Five-year OS was 71.4% (95% CI: 68.3%-74.7%) in the HVC cohort and 63.3% (56.8%-70.5%) in the LVC cohort ( P =0.012). Case volume was associated with both OS (LVC vs. HVC hazard ratio 1.40, 95% CI: 1.08-1.82, P =0.011) and DFS (hazard ratio 1.93, 95% CI: 1.57-2.37, P <0.001) at multivariable analyses. When applied to the study cohorts, the Sarculator nomograms showed good discrimination (Harrell C index between 0.68 and 0.73). The recalibrated nomograms showed good calibration in the HVC group, whereas the original nomograms showed good calibration in the LVC group.

CONCLUSIONS

New nomograms for patients with primary RPS treated with surgery at high-volume versus low-volume sarcoma reference centers are available in the Sarculator app.

Low local recurrence rates following marginal surgical resection of non-coelomic Atypical Lipomatous Tumours/Well-differentiated Liposarcomas

INTRODUCTION

High rates of local recurrence (LR) have been reported following resection of extremity Atypical lipomatous tumours/Well-differentiated liposarcomas (ALTs). This retrospective study of patients who underwent resection of primary deep extremity and trunk ALTs at a specialist sarcoma centre aims to assess morbidity and factors associated with low local recurrence rates (LRR).

METHODS

To review a homogeneous cohort of patients with low-grade disease, tumours with known high-risk histological features were excluded. Prognostic variables potentially influencing local recurrence (LR) (age, size, site, margin status, and histological findings) were analysed. Endpoints were LR, distant recurrence (DR) and local disease-free survival (LDFS).

RESULTS

127 patients were identified, with median follow-up of 54 months (0-235). Median tumour size was 17.5 cm (5-36). 85 % occurred in the lower limb. 93.7 % underwent marginal resection. No patients received radiotherapy. Median hospital stay was 3 days (0-16). 7.9 % returned to theatre for evacuation of haematoma or infected seroma and 18.1 % had outpatient seroma aspiration. Surgical margins were R0/R1 in 93.7 % of patients and R2 in 6.3 % with a LR rate of 8.4 % and 75 % respectively at median time of 54 months. One- and 5-year LDFS was 100 % and 88.4 %, respectively. DR rate was 0.8 % (1/127) this patient had pleomorphic liposarcomatous transformation on recurrence and subsequently developed distant metastases. No patients died of disease.

CONCLUSION

Function-preserving marginal resection of non-coelomic ALTs has low morbidity, low LR and extremely low rates of distant relapse. Patients with lower limb ALT were found to have significantly lower LR, which may impact follow-up protocols.

Risk Factors for the Development of Early Recurrence in Patients with Primary Retroperitoneal Sarcoma

BACKGROUND

Disease recurrence after retroperitoneal sarcoma (RPS) surgery is common, and resection may offer no benefit for patients who experience recurrence early. This study examined the incidence of early recurrence (EREC) in RPS patients, and the association between EREC and prognosis, aiming to identify the factors associated with EREC.

METHODS

Patients undergoing surgery for primary RPS from 2008 to 2019 at two tertiary RPS centers were analyzed. The study defined EREC as any evidence of local recurrence and/or distant metastases on the CT scan up to 6 months after surgery. Overall survival (OS) was calculated using the Kaplan-Meier method. A multivariable analysis was performed to identify independent predictors of EREC.

RESULTS

Of the 692 patients who underwent surgery during the study period, 657 were included in the analysis. Sixty-five of these patients (9.9%; 95% confidence interval [CI], 7.7-12.4%) developed EREC. Five-year OS was 3% for the patients with EREC versus 76% for those without EREC (p < 0.001). Patient characteristics were compared between the EREC and non-EREC patients, and EREC was found to be significantly associated with Eastern Cooperative Oncology Group (ECOG) performance status (p = 0.006), tumor histology (p = 0.002), tumor grading (p < 0.001), radiotherapy (p = 0.04), and postoperative complications measured as a comprehensive complications index value (p = 0.003). However, the only significant independent predictor of EREC in the multivariable analysis was grade 3 tumors, with an odds ratio of 14.8 (95% CI, 4.44-49.2; p < 0.001).

CONCLUSION

Early recurrence is associated with a poor prognosis, and a high tumor grade is an independent predictor for the development of EREC. Patients with EREC may benefit the most from new therapeutic options such as neoadjuvant chemotherapy.

Oncological Outcome After Lymph Node Dissection for Cutaneous Squamous Cell Carcinoma

BACKGROUND

Although cutaneous squamous cell carcinoma (cSCC) is common, lymph node metastases are relatively rare and are usually treated with lymph node dissection (LND). The aim of this study was to describe the clinical course and prognosis after LND for cSCC at all anatomical locations.

METHODS

A retrospective search at three centres was performed to identify patients with lymph node metastases of cSCC who were treated with LND. Prognostic factors were identified by uni- and multivariable analysis.

RESULTS

A total of 268 patients were identified with a median age of 74. All lymph node metastases were treated with LND, and 65% of the patients received adjuvant radiotherapy. After LND, 35% developed recurrent disease both locoregionally and distantly. Patients with more than one positive lymph node had an increased risk for recurrent disease. 165 (62%) patients died during follow-up of whom 77 (29%) due to cSCC. The 5-year OS- and DSS rate were 36% and 52%, respectively. Disease-specific survival was significantly worse in immunosuppressed patients, patients with primary tumors >2cm and patients with more than one positive lymph node.

CONCLUSIONS

This study shows that LND for patients with lymph node metastases of cSCC leads to a 5-year DSS of 52%. After LND, approximately one-third of the patients develop recurrent disease (locoregional and/or distant), which underscores the need for better systemic treatment options for locally advanced cSCC. The size of the primary tumor, more than one positive lymph node, and immunosuppression are independent predictors for risk of recurrence and disease-specific survival after LND for cSCC.

Prognosis of Patients with Cutaneous Angiosarcoma After Surgical Resection with Curative Intent: Is There a Difference Between the Subtypes?

BACKGROUND

The etiology of cutaneous angiosarcoma (cAS) may be idiopathic (I-cAS), or arise secondary to radiotherapy (RT-cAS), in chronic lymphedema (ST-cAS), or related to UV exposure (UV-cAS). The aim of this study was to evaluate oncological outcomes of different cAS subtypes.

PATIENTS AND METHODS

Non-metastatic cAS patients, treated with surgery for primary disease with curative intent, were retrospectively analyzed for oncological outcome, including local recurrence (LR), distant metastases (DM), and overall survival (OS).

RESULTS

A total of 234 patients were identified; 60 I-cAS, 122 RT-cAS, 9 ST-cAS, and 43 UV-cAS. The majority was female (78%), the median age was 66 years (IQR 57-76 years), the median tumor size was 4.4 cm (IQR 2.5-7.0 cm), and most common site of disease was the breast (59%). Recurrence was identified in 66% (44% LR and/or 41% DM), with a median follow up of 26.5 months (IQR 12-60 months). The 5-year OS was estimated at 50%, LRFS at 47%, and DMFS at 50%. There was no significant difference in LR, DM, or OS between the subtypes. Age < 65 years and administration of radiotherapy (RT) were significantly associated with lower LR rates (HR 0.560, 95% CI 0.3373-0.840, p = 0.005 and HR 0.421, 95% CI 0.225-0.790, p = 0.007, respectively), however no prognostic factors were identified for development of DM. Development of DM, but not LR (p = 0.052), was significantly associated with decreased OS (HR 6.486, 95% CI 2.939-14.318 p < 0.001).

CONCLUSION

We found no significant difference in oncological outcome between the different cAS subtypes. OS remains relatively poor, and RT is associated with lower LR rates.

Retrospective observational studies in ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society (CTOS) community of experts on the minimum requirements for the evaluation of activity of systemic treatments

BACKGROUND

In ultra-rare sarcomas (URS) the conduction of prospective, randomized trials is challenging. Data from retrospective observational studies (ROS) may represent the best evidence available. ROS implicit limitations led to poor acceptance by the scientific community and regulatory authorities. In this context, an expert panel from the Connective Tissue Oncology Society (CTOS), agreed on the need to establish a set of minimum requirements for conducting high-quality ROS on the activity of systemic therapies in URS.

METHODS

Representatives from > 25 worldwide sarcoma reference centres met in November 2020 and identified a list of topics summarizing the main issues encountered in ROS on URS. An online survey on these topics was distributed to the panel; results were summarized by descriptive statistics and discussed during a second meeting (November 2021).

RESULTS

Topics identified by the panel included the use of ROS results as external control data, the criteria for contributing centers selection, modalities for ensuring a correct pathological diagnosis and radiologic assessment, consistency of surveillance policies across centers, study end-points, risk of data duplication, results publication. Based on the answers to the survey (55 of 62 invited experts) and discussion the panel agreed on 18 statements summarizing principles of recommended practice.

CONCLUSIONS

These recommendations will be disseminated by CTOS across the sarcoma community and incorporated in future ROS on URS, to maximize their quality and favor their use as control data when results from prospective studies are unavailable. These recommendations could help the optimal conduction of ROS also in other rare tumors.

Association Between Ageing and Short-Term Survival Outcomes in Patients Undergoing Surgery for Primary Retroperitoneal Sarcoma

BACKGROUND

As the population ages, more elderly patients are receiving surgery for retroperitoneal sarcoma (RPS). However, high-quality data investigating associations between ageing and prognosis are lacking. Our study aimed to investigate whether ageing is associated with inferior short-term survival outcomes after RPS surgery.

PATIENTS AND METHODS

Patients undergoing surgery for primary RPS between 2008 and 2019 at two tertiary sarcoma centres were analysed. The primary outcome was 1-year mortality, and the primary explanatory variable was patient age, classified as: < 55, 55-64, 65-74 or 75+ years.

RESULTS

The 692 patients undergoing surgery (mean age 60.8 ± 13.8 years) had a 1-year mortality rate of 9.4%, which differed significantly by age (p < 0.001), with rates of 7.2%, 6.9%, 8.7% and 22.8% for the < 55, 55-64, 65-74 and 75+ years groups, respectively. The distribution of causes of death also differed significantly by age (p = 0.023), with 22% and 28% of deaths in the 65-74 and 75+ years groups caused by post-operative complications, versus none in the < 55 and 55-64 years groups. On multivariable analysis, age of 75+ years (versus < 55 years) was a significant independent predictor of 1-year mortality [odds ratio (OR) 7.05, 95% confidence interval (CI) 2.63-18.9, p < 0.001]; no significant increase in risk was observed in the 55-64 (OR 0.72, 95% CI 0.28-1.87) or 65-74 (OR 0.89, 95% CI 0.37-2.15) years groups.

CONCLUSIONS

Post-operative complications are an important cause of deaths in elderly patients. These findings are relevant to decision-making and counselling when surgery is considered for patients with RPS.

Radiomic Features From Diffusion-Weighted MRI of Retroperitoneal Soft-Tissue Sarcomas Are Repeatable and Exhibit Change After Radiotherapy

Background

Size-based assessments are inaccurate indicators of tumor response in soft-tissue sarcoma (STS), motivating the requirement for new response imaging biomarkers for this rare and heterogeneous disease. In this study, we assess the test-retest repeatability of radiomic features from MR diffusion-weighted imaging (DWI) and derived maps of apparent diffusion coefficient (ADC) in retroperitoneal STS and compare baseline repeatability with changes in radiomic features following radiotherapy (RT).

Materials and Methods

Thirty patients with retroperitoneal STS received an MR examination prior to treatment, of whom 23/30 were investigated in our repeatability analysis having received repeat baseline examinations and 14/30 patients were investigated in our post-treatment analysis having received an MR examination after completing pre-operative RT. One hundred and seven radiomic features were extracted from the full manually delineated tumor region using PyRadiomics. Test-retest repeatability was assessed using an intraclass correlation coefficient (baseline ICC), and post-radiotherapy variance analysis (post-RT-IMS) was used to compare the change in radiomic feature value to baseline repeatability.

Results

For the ADC maps and DWI images, 101 and 102 features demonstrated good baseline repeatability (baseline ICC > 0.85), respectively. Forty-three and 2 features demonstrated both good baseline repeatability and a high post-RT-IMS (>0.85), respectively. Pearson correlation between the baseline ICC and post-RT-IMS was weak (0.432 and 0.133, respectively).

Conclusions

The ADC-based radiomic analysis shows better test-retest repeatability compared with features derived from DWI images in STS, and some of these features are sensitive to post-treatment change. However, good repeatability at baseline does not imply sensitivity to post-treatment change.

Management of Locally Recurrent Retroperitoneal Sarcoma in the Adult: An Updated Consensus Approach from the Transatlantic Australasian Retroperitoneal Sarcoma Working Group

BACKGROUND

Surgery is the mainstay of treatment for retroperitoneal sarcoma (RPS), but local recurrence is common. Biologic behavior and recurrence patterns differ significantly among histologic types of RPS, with implications for management. The Transatlantic Australasian RPS Working Group (TARPSWG) published a consensus approach to primary RPS, and to complement this, one for recurrent RPS in 2016. Since then, additional studies have been published, and collaborative discussion is ongoing to address the clinical challenges of local recurrence in RPS.

METHODS

An extensive literature search was performed, and the previous consensus statements for recurrent RPS were updated after review by TARPSWG members. The search included the most common RPS histologic types: liposarcoma, leiomyosarcoma, solitary fibrous tumor, undifferentiated pleomorphic sarcoma, and malignant peripheral nerve sheath tumor.

RESULTS

Recurrent RPS management was evaluated from diagnosis to follow-up evaluation. For appropriately selected patients, resection is safe. Nomograms currently are available to help predict outcome after resection. These and other new findings have been combined with expert recommendations to provide 36 statements, each of which is attributed a level of evidence and grade of recommendation. In this updated document, more emphasis is placed on histologic type and clarification of the intent for surgical treatment, either curative or palliative. Overall, the fundamental tenet of optimal care for patients with recurrent RPS remains individualized treatment after multidisciplinary discussion by an experienced team with expertise in RPS.

CONCLUSIONS

Updated consensus recommendations are provided to help guide decision-making for treatment of locally recurrent RPS and better selection of patients who would potentially benefit from surgery.

Frailty in Very Elderly Patients is Not Associated with Adverse Surgical or Oncological Outcomes in Extremity Surgery for Soft Tissue Sarcoma

Background

While surgery remains the mainstay of treatment for limb sarcoma, extreme old age is a relative contraindication to oncological surgery.

Methods

Patients >80 years referred with primary extremity soft-tissue sarcoma (ESTS) between 2007 and 2016 were retrospectively reviewed. Prognostic variables, including ASA status and Clinical Frailty Scores, were collected. Endpoints were perioperative morbidity, locoregional (LRR) and distant recurrence (DR), disease-specific survival (DSS) adjusted using competing risk modelling, and overall survival (OS).

Results

A total of 141 primary tumours were identified, with 116 undergoing resections. Main motives for nonoperative management were severe frailty or significant comorbidity (56.0%). The operative group had a median age of 84 (range 80-96) years and median follow-up of 16 months (range 0-95). 45.7% of patients received radiotherapy. Median hospital stay was 7 (range 0-40) days, with frailty (p = 0.25) and ASA (p = 0.28) not associated with prolonged admission. 12.9% developed significant complications, with one perioperative mortality.

24.1% had LRR, occurring at a median of 14.5 months. All patients with reported DR (28.4%), except one, died of their disease. Frailty did not confer a significant difference in adjusted LRFS (p = 0.95) and DMFS (p = 0.84). One- and 5-year adjusted DSS and OS was 87.0% versus 74.9% and 62.3% versus 27.4%, respectively. Frailty (CFS ≥4) was associated with worse OS (hazard ratio [HR] 2.49; 95% confidence interval [CI] 1.51-4.12; p < 0.001), however not with adjusted DSS (p = 0.16). Nonoperative management conferred a 1- and 5-year adjusted DSS was 58.3% and 44.4%, respectively.

Conclusions

Extremity surgery for sarcoma is well tolerated in the frail very elderly population with low morbidity and comparable oncological outcomes.

Longitudinal prognostication in retroperitoneal sarcoma survivors: Development and external validation of two dynamic nomograms

PURPOSE

The aim of this study was to create and validate dynamic nomograms to predict overall survival (OS) and disease-free survival (DFS) at different time points during follow-up in patients who had undergone resection of primary retroperitoneal sarcoma (RPS).

METHODS

Patients with primary RPS operated upon between 2002 and 2017 at four and six referral centres comprised the development and external validation cohorts, respectively. Landmark analysis and multivariable Cox models were used to develop dynamic nomograms. Variables were selected using two backward procedures based on the Akaike information criterion. The prediction window was fixed at 5 years. Nomogram performances were tested in terms of calibration and discrimination on the development and validation cohorts.

RESULTS

Development and validation cohorts totalled 1357 and 487 patients (OS analysis), and 1309 and 452 patients (DFS analysis), respectively. The final OS model included age, landmark time (T_LM), tumour grade, completeness of resection and occurrence of local/distant recurrence. The final DFS model included T_LM, histologic subtype, tumour size, tumour grade, multifocality and the interaction terms between T_LM and size, grade and multifocality. For OS, Harrell C indices were higher than 0.7 in both cohorts, indicating very good discriminative capability. For DFS, Harrell C indices were between 0.64 and 0.72 in the development cohort and 0.62 and 0.68 in the validation cohort. Calibration plots showed good agreement between predicted and observed outcomes.

CONCLUSION

Validated nomograms are available to predict the 5-year OS and DFS probability at different time points throughout the first 5 years of follow-up in RPS survivors.

Gastrointestinal leiomyosarcoma demonstrate a predilection for distant recurrence and poor response to systemic treatments

BACKGROUND

Primary leiomyosarcoma (LMS) of the gastrointestinal (GI) tract is rare. Limited literature exists regarding the clinical characteristics and outcome for patients with localised and metastatic disease.

METHODS

A retrospective chart review was performed for patients greater than 18 years of age diagnosed with GI LMS at The Royal Marsden Hospital between 1 January 2000-1 May 2020. Descriptive statistics were performed. Patients were censored at data cut-off date of 27 June 2020.

RESULTS

Forty-six patients with a median age at diagnosis of 54 years (range 25-85) were identified. Fifteen percent (n = 7) of patients previously received abdominal radiation for an unrelated cancer. All patients with localised disease (n = 36) had resection with oncological margins. For patients who underwent potentially curative surgery, median recurrence-free survival (mRFS) was 13 months (0.4-183 months), and half of these patients (n = 18) developed recurrent disease post resection (distant n = 16, local n = 2). Median overall survival (mOS) was 27 months for patients with distant recurrence. Twenty-one percent (n = 10) of patients presented with synchronous metastatic disease and their mOS was 19 months. Median progression-free survival (mPFS) for patients treated with conventional chemotherapy ranged from 2.0 to 8.0 months.

CONCLUSION

The risk of recurrence is significant, and recurrence-free survival was short even with complete oncologic resection. The relationship of prior abdominal radiotherapy to the development of GI LMS warrants further investigation. Outcomes with systemic therapy for metastatic disease were poor and there is a need for the development of more effective systemic therapies.

Ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society community of experts on the incidence threshold and the list of entities

BACKGROUND

Among sarcomas, which are rare cancers, many types are exceedingly rare; however, a definition of ultra-rare cancers has not been established. The problem of ultra-rare sarcomas is particularly relevant because they represent unique diseases, and their rarity poses major challenges for diagnosis, understanding disease biology, generating clinical evidence to support new drug development, and achieving formal authorization for novel therapies.

METHODS

The Connective Tissue Oncology Society promoted a consensus effort in November 2019 to establish how to define ultra-rare sarcomas through expert consensus and epidemiologic data and to work out a comprehensive list of these diseases. The list of ultra-rare sarcomas was based on the 2020 World Health Organization classification, The incidence rates were estimated using the Information Network on Rare Cancers (RARECARENet) database and NETSARC (the French Sarcoma Network's clinical-pathologic registry). Incidence rates were further validated in collaboration with the Asian cancer registries of Japan, Korea, and Taiwan.

RESULTS

It was agreed that the best criterion for a definition of ultra-rare sarcomas would be incidence. Ultra-rare sarcomas were defined as those with an incidence of approximately ≤1 per 1,000,000, to include those entities whose rarity renders them extremely difficult to conduct well powered, prospective clinical studies. On the basis of this threshold, a list of ultra-rare sarcomas was defined, which comprised 56 soft tissue sarcoma types and 21 bone sarcoma types.

CONCLUSIONS

Altogether, the incidence of ultra-rare sarcomas accounts for roughly 20% of all soft tissue and bone sarcomas. This confirms that the challenges inherent in ultra-rare sarcomas affect large numbers of patients.

Management of Primary Retroperitoneal Sarcoma (RPS) in the Adult: An Updated Consensus Approach from the Transatlantic Australasian RPS Working Group

BACKGROUND

Retroperitoneal soft tissue sarcomas comprise a heterogeneous group of rare tumors of mesenchymal origin that include several well-defined histologic subtypes. In 2015, the Transatlantic Australasian RPS Working Group (TARPSWG) published consensus recommendations for the best management of primary retroperitoneal sarcoma (RPS). Since then, through international collaboration, new evidence and knowledge have been generated, creating the need for an updated consensus document.

METHODS

The primary aim of this study was to critically evaluate the current evidence and develop an up-to-date consensus document on the approach to these difficult tumors. The resulting document applies to primary RPS that is non-visceral in origin, with exclusion criteria as previously described. The relevant literature was evaluated and an international group of experts consulted to formulate consensus statements regarding the best management of primary RPS. A level of evidence and grade of recommendation were attributed to each new/updated recommendation.

RESULTS

Management of primary RPS was considered from diagnosis to follow-up. This rare and complex malignancy is best managed by an experienced multidisciplinary team in a specialized referral center. The best chance of cure is at the time of primary presentation, and an individualized management plan should be made based on the 29 consensus statements included in this article, which were agreed upon by all of the authors. Whenever possible, patients should be enrolled in prospective trials and studies.

CONCLUSIONS

Ongoing international collaboration is critical to expand upon current knowledge and further improve outcomes of patients with RPS. In addition, prospective data collection and participation in multi-institution trials are strongly encouraged.

CT diagnosis of ilioinguinal lymph node metastases in melanoma using radiological characteristics beyond size and asymmetry

Background

Diagnosis of lymph node (LN) metastasis in melanoma with non-invasive methods is challenging. The aim of this study was to evaluate the diagnostic accuracy of six LN characteristics on CT in detecting melanoma-positive ilioinguinal LN metastases, and to determine whether inguinal LN characteristics can predict pelvic LN involvement.

Methods

This was a single-centre retrospective study of patients with melanoma LN metastases at a tertiary cancer centre between 2008 and 2016. Patients who had preoperative contrast-enhanced CT assessment and ilioinguinal LN dissection were included. CT scans containing significant artefacts obscuring the pelvis were excluded. CT scans were reanalysed for six LN characteristics (extracapsular spread (ECS), minimum axis (MA), absence of fatty hilum (FH), asymmetrical cortical nodule (CAN), abnormal contrast enhancement (ACE) and rounded morphology (RM)) and compared with postoperative histopathological findings.

Results

A total of 90 patients were included. Median age was 58 (range 23–85) years. Eighty-eight patients (98 per cent) had pathology-positive inguinal disease and, of these, 45 (51 per cent) had concurrent pelvic disease. The most common CT characteristics found in pathology-positive inguinal LNs were MA greater than 10 mm (97 per cent), ACE (80 per cent), ECS (38 per cent) and absence of RM (38 per cent). In multivariable analysis, inguinal LN characteristics on CT indicative of pelvic disease were RM (odds ratio (OR) 3.3, 95 per cent c.i. 1.2 to 8.7) and ECS (OR 4.2, 1.6 to 11.3). Cloquet’s node is known to be a poor predictor of pelvic spread. Pelvic LN disease was present in 50 per cent patients, but only 7 per cent had a pathology-positive Cloquet’s node.

Conclusion

Additional CT radiological characteristics, especially ECS and RM, may improve diagnostic accuracy and aid clinical decisions regarding the need for inguinal or ilioinguinal dissection.

Has the Outcome for Patients Who Undergo Resection of Primary Retroperitoneal Sarcoma Changed Over Time? A Study of Time Trends During the Past 15 years

BACKGROUND

This study aimed to investigate changes in treatment strategy and outcome for patients with primary retroperitoneal sarcoma (RPS) undergoing resection at referral centers during a recent period.

METHODS

The study enrolled consecutive adult patients with primary non-metastatic RPS who underwent resection with curative intent between 2002 and 2017 at 10 referral centers. The patients were grouped into three periods according to date of surgery: t1 (2002-2006), t2 (2007-2011), and t3 (2012-2017). Five-year overall survival (OS), disease-specific survival (DSS), and crude cumulative incidence (CCI) of local recurrence (LR) and distant metastasis (DM) were calculated. Multivariable analyses for OS and DSS were performed.

RESULTS

The study included 1942 patients. The median follow-up period after resection varied from 130 months (interquartile range [IQR], 124-141 months) in t1 to 37 months (IQR, 35-39 months) in t3. The 5-year OS was 61.2% (95% confidence interval [CI], 56.4-66.3%) in t1, 67.0% (95 CI, 63.2-71.0%) in t2, and 71.9% (95% CI, 67.7-76.1%) in t3. The rate of macroscopically incomplete resection (R2) was 7.1% in t1 versus 4.7% in t3 (p = 0.066). The median number of resected organs increased over time (p < 0.001). In the multivariable analysis resection during t3 was associated with better OS and DSS. The 90-day postoperative mortality improved over time (4.3% in t1 to 2.3% in t3; p = 0.031). The 5-year CCI of LR and DM did not change significantly over time.

CONCLUSIONS

The long-term survival of patients who underwent resection for primary RPS has increased during the past 15 years. This increased survival is attributable to better patient selection for resection, quality of surgery, and perioperative patient management.

Robotic surgery for gastric gastrointestinal stromal tumors: A single center case series

BACKGROUND AND OBJECTIVES

The aim of surgical treatment of gastrointestinal stromal tumors (GIST) is a microscopically complete resection. Initial indications for laparoscopic surgery were limited to smaller tumors, in favorable locations. Over time, indications for minimal invasive surgery (MIS) have expanded, however concerns remain when considering resection of larger GISTs. Our aims were to assess the utility of robotic resection of gastric GISTs for challenging tumors.

METHODS

GIST resections, in this study were performed using the Intuitive Da Vinci Surgical Xi System. GIST's were considered challenging if tumor size was >50 mm at the time of surgery and/or the location of the tumor was type II, III, or IV using Privette/Al-Thanai classification.

RESULTS

Robotic resections were performed on 12 consecutive patients, 83% were considered challenging cases, 6 out of 12 for location and 5 out of 12 for size. Initial median tumor size on imaging was 53.7 mm, and post-imatinib was 45.8 mm. All tumors were removed with clear margins (R0) via wedge resections, with no complications. Median operative time was 192 minutes (95-250). Length of hospital stay was 2 days (2-6).

CONCLUSIONS

Robotic resection of gastric GIST's appears oncologically safe, and may expand the benefits of MIS to a greater cohort of complex cases.

Epithelioid malignant peripheral nerve sheath tumor arising in schwannoma

Epithelioid malignant peripheral nerve sheath tumor (EMPNST, malignant epithelioid schwannoma) is a rare variant of malignant peripheral nerve sheath tumor that has morphologic and immunophenotypic overlap with a variety of epithelioid neoplasms. Because of its rarity it may be potentially underrecognized. We describe a case arising in the subcutis of the thigh in a 25 year-old female, and discuss the pathologic features and differential diagnosis.

Adequate surgical margins for dermatofibrosarcoma protuberans - A multi-centre analysis

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive tumour. Adequate margins have a positive impact on recurrence rates. The aim of this study is to assess how adequate margins are achieved and secondly which additional treatment modalities might be necessary to achieve adequate margins.

MATERIAL & METHODS

Patients with DFSP treated between 1991 and 2016 at three tertiary centres were included. Patient- and tumour characteristics were obtained from a prospectively held database and patient files.

RESULTS

A total of 279 patients with a median age of 39 (Interquartile range [IQ], 31-50) years and a median follow-up of 50 (IQ, 18-96) months were included. When DFSP was preoperatively confirmed by biopsy and resected with an oncological operation in a tertiary centre, in 86% was had clear pathological margins after one excision. Wider resection margins were significantly correlated with more reconstructions (p = 0.002). A substantial discrepancy between the primary surgical macroscopic and the pathological margins was found with a median difference of 22 (range, 10-46) mm (Fig. 1). There was no significant influence of the width of the pathological clear margins (if > 1 mm) and the recurrence rate (p = 0.710).

CONCLUSION

The wider the resection margins, the more likely it is to obtain clear pathological margins, but the more likely patients will need any form of reconstruction after resection. The aim of the primary excision should be wide surgical resection, where the width of the margin should be balanced against the need for reconstructions and surgical morbidity.

Development and external validation of a dynamic prognostic nomogram for primary extremity soft tissue sarcoma survivors

BACKGROUND

Prognostic nomograms for patients with extremity soft tissue sarcoma (eSTS) typically predict survival or the occurrence of local recurrence or distant metastasis at time of surgery. Our aim was to develop and externally validate a dynamic prognostic nomogram for overall survival in eSTS survivors for use during follow-up.

METHODS

All primary eSTS patients operated with curative intent between 1994 and 2013 at three European and one Canadian sarcoma centers formed the development cohort. Patients with Fédération Française des Centres de Lutte Contre le Cancer (FNCLCC) grade II and grade III eSTS operated between 2000 and 2016 at seven other European reference centers formed the external validation cohort. We used a landmark analysis approach and a multivariable Cox model to create a dynamic nomogram; the prediction window was fixed at five years. A backward procedure based on the Akaike Information Criterion was adopted for variable selection. We tested the nomogram performance in terms of calibration and discrimination.

FINDINGS

The development and validation cohorts included 3740 and 893 patients, respectively. The variables selected applying the backward procedure were patient's age, tumor size and its interaction with landmark time, tumor FNCLCC grade and its interaction with landmark time, histology, and both local recurrence and distant metastasis (as first event) indicator variables. The nomogram showed good calibration and discrimination. Harrell C indexes at different landmark times were between 0.776 (0.761-0.790) and 0.845 (0.823-0.862) in the development series and between 0.675 (0.643-0.704) and 0.810 (0.775-0.844) in the validation series.

INTERPRETATION

A new dynamic nomogram is available to predict 5-year overall survival at different times during the first three years of follow-up in patients operated for primary eSTS. This nomogram allows physicians to update the individual survival prediction during follow-up on the basis of baseline variables, time elapsed from surgery and first-event history.

The adequacy of tissue microarrays in the assessment of inter- and intra-tumoural heterogeneity of infiltrating lymphocyte burden in leiomyosarcoma

The characterisation and clinical relevance of tumour-infiltrating lymphocytes (TILs) in leiomyosarcoma (LMS), a subtype of soft tissue sarcoma that exhibits histological heterogeneity, is not established. The use of tissue microarrays (TMA) in studies that profile TIL burden is attractive but given the potential for intra-tumoural heterogeneity to introduce sampling errors, the adequacy of this approach is undetermined. In this study, we assessed the histological inter- and intra-tumoural heterogeneity in TIL burden within a retrospective cohort of primary LMS specimens. Using a virtual TMA approach, we also analysed the optimal number of TMA cores required to provide an accurate representation of TIL burden in a full tissue section. We establish that LMS have generally low and spatially homogenous TIL burdens, although a small proportion exhibit higher levels and more heterogeneous distribution of TILs. We show that a conventional and practical number (e.g. ≤3) of TMA cores is adequate for correct ordinal categorisation of tumours with high or low TIL burden, but that many more cores (≥11) are required to accurately estimate absolute TIL numbers. Our findings provide a benchmark for the design of future studies aiming to define the clinical relevance of the immune microenvironments of LMS and other sarcoma subtypes.

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.

STRASS (EORTC 62092): A phase III randomized study of preoperative radiotherapy plus surgery versus surgery alone for patients with retroperitoneal sarcoma

11001

Background: The predominant pattern of failure of retroperitoneal sarcoma (RPS), frequently associated with subsequent death, is locoregional recurrence. Unlike in limbs, the efficacy of radiotherapy (RT) combined with surgery is not established. Methods: STRASS is a randomized, multicentre, international trial. Eligible patients had histologically-proven localized primary RPS, operable and suitable for radiotherapy. Patients were randomized 1:1 to preoperative RT (3D-CRT or IMRT) 50.4 Gy followed by surgery (RT/S group) or surgery alone (S group), stratified by hospital and performance status (0-1 vs 2). Primary endpoint is abdominal recurrence-free survival (ARFS; local relapse after complete resection, peritoneal sarcomatosis, R2 surgery, progressive disease during RT or unresectable disease). IDMC recommended a sensitivity analysis in which local progression on RT is not regarded as an event for patients who subsequently achieve complete surgical resection. Secondary endpoints were recurrence-free survival, overall survival, acute toxicity profile of RT, perioperative and late complications, and QoL. The study was designed to provide 90% power to show an increase of 20% in the 5-year ARFS rate, from 50% to 70% (corresponding to a HR of 0.52) at 2-sided 5% significance level. Results: 266 patients from Europe, USA and Canada were randomized between January 2012 and April 2017; 198 patients (74.5 %) had liposarcoma (LPS). Eighteen patients were designated ineligible. Overall rate of re-operation for any complication was 10.1%: 13 (10.9%) and 12 (9.4%) patients in RT/S versus S groups. 19 pts (14%) progressed during RT, 4 of whom did not undergo surgery. 3-year ARFS was 60.4% (95% Confidence interval (CI) 51.4-68.2%) and 58.7% (49.5- 66.7%) (HR = 1.01, 95%CI 0.71-1.44, p=0.954) in RT/S versus S groups. In the sensitivity analysis, 3-year ARFS was 66.0% (57.1-73.5%) and 58.7% (49.5-66.7%) in RT/S versus S groups (HR = 0.84, 95% CI 0.58-1.21, p=0.340). In the LPS subgroup, 3-year ARFS (sensitivity analysis) was 71.6% (61.3-79.6%) and 60.4% (49.8-69.5%) in RT/S versus S groups (HR = 0.64, 95%CI 0.40-1.01, p =0.049). Conclusion: STRASS failed to demonstrate a benefit of pre-operative RT for RPS. In the exploratory analysis, preoperative RT may benefit the LPS subgroup. Funding Source: EORTC and EUROSARC FP7 278472. Clinical trial information: EORTC 62092.

Radiotherapy for retroperitoneal liposarcoma: A report from the Transatlantic Retroperitoneal Sarcoma Working Group

Background

The current study investigated the role of radiotherapy (RT) in patients with primary nonmetastatic retroperitoneal liposarcomas.

Methods

A total of 607 patients with localized retroperitoneal well‐differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas (DDLPS) underwent surgical resection with or without RT at 8 high‐volume sarcoma centers (234 patients with WDLPS, 242 patients with grade 1 to 2 DDLPS, and 131 patients with grade 3 DDLPS; grading was performed according to the National Federation of Centers for the Fight Against Cancer [Federation Nationale des Centres de Lutte Contre le Cancer; FNCLCC]). RT was administered in 19.7%, 34.7%, and 35.1%, respectively, of these 3 cohorts. Overall survival (OS) was estimated using the Kaplan‐Meier method, and the incidences of local recurrence and distant metastasis (DM) were estimated in a competing risk framework. To account for bias consistent with nonrandom RT assignment, propensity scores were estimated. Cox univariable analysis of the association between RT and oncological endpoints was performed by applying inverse probability of treatment weighting (IPTW) using propensity scores.

Results

Age, tumor size, and the administration of chemotherapy were found to be significantly imbalanced between patients who did and did not undergo RT in all cohorts. IPTW largely removed imbalances in key prognostic variables. Although the 8‐year local recurrence incidences in patients treated with surgery plus RT versus surgery only were 11.8% and 39.2%, respectively, for patients with WDLPS (P = .011;); 29.0% and 56.7%, respectively, for patients with grade 1 to 2 DDLPS (P = .008); and 29.8% and 43.7%, respectively, for patients with grade 3 DDLPS (P = .025), this significant benefit was lost after IPTW analyses. There were no significant differences noted with regard to DM and OS between irradiated and unirradiated patients across all 3 cohorts.

Conclusions

Perioperative RT was found to be associated with better local control in univariable unadjusted analysis in all 3 cohorts, but not after accounting for imbalances in prognostic variables. RT did not impact on DM or OS. The appropriate selection of RT in this disease remains challenging. The results of the European Organization for Research and Treatment of Cancer (EORTC)–Soft Tissue and Bone Sarcoma Group (STBSG) 62092‐22092 prospective randomized trial are awaited.

In the current study, the addition of radiotherapy to curative surgery is analyzed in a large, retrospective, multi‐institutional series of patients with primary retroperitoneal liposarcoma. Although there appears to be an association with better local control and outcome, this benefit is lost after propensity score adjustment. The authors currently are awaiting the results of the European Organization for Research and Treatment of Cancer–Soft Tissue and Bone Sarcoma Group 62092‐22092 prospective randomized trial examining the value of preoperative radiotherapy.

Regional chemotherapy by isolated limb perfusion prior to surgery compared with surgery and post-operative radiotherapy for primary, locally advanced extremity sarcoma: a comparison of matched cohorts

Background

Induction chemotherapy by isolated limb perfusion (ILP) with melphalan and tumour necrosis factor-α is an effective strategy to facilitate limb-conserving surgery in locally advanced extremity sarcoma. In a comparison of cohorts matched for grade, size and surgical resectability, we compared the outcome of patients undergoing induction ILP prior to limb-conserving surgery and selective post-operative radiotherapy with patients undergoing limb-conserving surgery and routine post-operative radiotherapy.

Methods

Patients with primary, grade 2/3 sarcomas of the lower limbs over 10 cm in size were identified from prospectively maintained databases at 3 centres. Patients treated at a UK centre underwent limb-conserving surgery and post-operative radiotherapy (Standard cohort). Patients at two German centres underwent induction ILP, limb-conserving surgery and selective post-operative radiotherapy (ILP cohort).

Results

The Standard cohort comprised 80 patients and the ILP cohort 44 patients. Both cohorts were closely matched in terms of tumour size, grade, histological subtype and surgical resectability. The median age was greater in the Standard vs the ILP cohort (60.5 years vs 56 years, p = 0.033). The median size was 13 cm in both cohorts. 5-year local-recurrence (ILP 12.2%, Standard 20.1%, p = 0.375) and distant metastases-free survival rates (ILP 49.6%, Standard 46.0% p = 0.821) did not differ significantly between cohorts. Fewer patients received post-operative radiotherapy in the ILP cohort compared with the Standard cohort (27% vs 82%, p < 0.001).

Conclusion

In comparative cohorts, the outcomes of patients undergoing induction ILP prior to surgery did not differ from those undergoing standard management, although induction ILP was associated with a reduced need for adjuvant radiation.

Endometrial Stromal Sarcoma With Hyalinizing Giant Rosettes, Mimicking Low-Grade Fibromyxoid Sarcoma

We highlight a rare variant pattern of low-grade endometrial stromal sarcoma showing extensive collagenous rosette formation, closely mimicking low-grade fibromyxoid sarcoma. Additionally, this neoplasm showed diffuse and strong expression of muscle markers, favoring an initial diagnosis of leiomyosarcoma. Reverse transcription-polymerase chain reaction showed the presence of JAZF1-SUZ12 fusion transcripts, and this highlights the broad morphologic and immunophenotypic spectrum of endometrial stromal sarcoma.

Post-relapse outcomes after primary extended resection of retroperitoneal sarcoma: A report from the Trans-Atlantic RPS Working Group

BACKGROUND

Despite a radical surgical approach to primary retroperitoneal sarcoma (RPS), many patients experience locoregional and/or distant recurrence. The objective of this study was to analyze post-relapse outcomes for patients with RPS who had initially undergone surgical resection of their primary tumor at a specialist center.

METHODS

All consecutive patients who underwent macroscopically complete resection for primary RPS at 8 high volume centers from January 2002 to December 2011 were identified, and those who developed local recurrence (LR) only, distant metastasis (DM) only, or synchronous local recurrence and distant metastasis (LR+DM) during the follow-up period were included. Overall survival (OS) was calculated for all groups, as was the crude cumulative incidence of a second recurrence after the first LR. Multivariate analyses for OS were performed.

RESULTS

In an initial series of 1007 patients with primary RPS, 408 patients developed recurrent disease during the follow-up period. The median follow-up from the time of recurrence was 41 months. The median OS was 33 months after LR (n = 219), 25 months after DM (n = 146), and 12 months after LR+DM (n = 43), and the 5-year OS rates were 29%, 20%, and 14%, respectively. Predictors of OS after LR were the time interval to LR and resection of LR, while histologic grade approached significance. For DM, significant predictors of OS were the time interval to DM and histologic subtype. The subgroup of patients who underwent resection of recurrent disease had a longer median OS than patients who did not undergo resection.

CONCLUSIONS

Relapse of RPS portends high disease-specific mortality. Patients with locally recurrent or metastatic disease should be considered for resection. Cancer 2017;123:1971-1978. © 2017 American Cancer Society.

Selective marginal resections in the management of aggressive angiomyxomas

AIM

Aggressive angiomyxomas (AA) are rare tumors, most commonly presenting in the pelvis of women of childbearing age. This study presents the results of selective marginal resection of this disease in patients managed at a single institution.

METHODS

Patients diagnosed with AA from July 2001 to July 2015 were identified from a prospectively maintained histopathology database.

RESULTS

Seventeen patients were diagnosed with AA in the study period. The median age at diagnosis was 48 years. Females were more commonly affected with a M:F of 1:8.5. The most common differential diagnoses were an ischiorectal abscess or Bartholin's cyst. Fifteen cases occurred in the pelvis, with two cases at other sites. Median maximum tumor diameter was 10 cm. Of the pelvic cases, 12 were managed operatively via perineal, abdominal, or abdominoperineal approaches. Excision was performed in a marginal fashion with minimal morbidity. Local recurrence developed in 58.3% with a median local recurrence free survival of 25 months. No patients developed metastatic disease or died from disease.

CONCLUSION

AA are rare tumors with a propensity for local recurrence. Atypical presentations of other perineal pathologies should prompt further investigation. Surgery should be reserved for symptomatic patients and is associated with low rates of morbidity. J. Surg. Oncol. 2016;114:828-832. © 2016 2016 Wiley Periodicals, Inc.

Endometriosis of Extra-Abdominal Soft Tissues

While endometriosis, defined as the presence of endometrial tissue in extrauterine sites, is most frequently encountered within the peritoneal cavity, a small but significant proportion of cases occur at extra-abdominal soft tissue sites, particularly in relation to previous abdominal surgery. We reviewed the cases of endometriosis of soft tissue sites seen at a tertiary soft tissue center. All cases of extra-abdominal soft tissue endometriosis diagnosed at this institution over a 13-year period were reviewed, and clinical and pathologic findings were recorded. Forty-five patients had diagnoses of soft tissue endometriosis and there were 34 diagnostic biopsies and 26 surgical excision specimens. All but 1 case were abdominal wall lesions, with 1 located in the upper arm. A total of 33 patients presented with lesions in scars of previous operations (31 in Pfannenstiel incisions for Caesarean sections, presenting with a median interval of 6 years (range 1-16 years) following surgery). The lesions ranged in size from 1 to 8 cm (median 3.5 cm). One case showed decidualized stroma with trophoblast cells, while 2 had secondary adenocarcinoma arising from endometriosis. Eighteen cases were tested for β-catenin expression immunohistochemically, of which 5 showed at least focal nuclear positivity in the surrounding fibrous tissue (although not within glands or stroma). Soft tissue endometriosis is seen most commonly in surgical scars, particularly following Caesarean sections. Spontaneous endometriosis also most commonly occurs in the abdominal wall, although can occur exceptionally at unusual sites, such as extremities. Secondary changes, including carcinomas, can arise from endometriosis. The differential diagnosis of these lesions includes fibromatosis, which may be erroneously diagnosed on small, nonrepresentative core biopsy specimens.

Patterns of disease relapse in primary extremity soft-tissue sarcoma

Background

Extremity soft-tissue sarcomas comprise a range of distinct histological subtypes. This study aimed to characterize the patterns of disease relapse in patients undergoing resection of primary extremity soft-tissue sarcoma.

Methods

All patients who had resection of primary extremity soft-tissue sarcoma at the Royal Marsden Hospital between January 2004 and January 2014 were identified from an institutional database.

Results

In the period examined, 556 patients underwent resection. The most common histological subtypes were undifferentiated pleomorphic sarcoma (169 patients, 30·4 per cent), well differentiated liposarcoma (63, 11·3 per cent), myxoid liposarcoma (62, 11·2 per cent), myxofibrosarcoma (54, 9·7 per cent) and leiomyosarcoma (39, 7·0 per cent). Local recurrence-free survival (LRFS) did not differ significantly between histological subtypes (P = 0·222). Distant metastasis-free survival (DMFS) and disease-specific survival (DSS) were found to differ significantly between subtypes (P &lt; 0·001 for both DMFS and DSS), with the worst outcomes in patients with undifferentiated pleomorphic sarcoma (5-year survival rate: 56·8 (95 per cent c.i. 52·5 to 61·1) per cent for DMFS; 60·1 (55·6 to 64·6) per cent for DSS). However, on multivariable analysis, histological subtype was not found to be independently prognostic for LRFS, DMFS or DSS. Metastatic disease developed in 149 patients, with the lungs being the most common site of first metastasis (120 patients, 80·5 per cent). The site of first metastasis differed between subtypes, with extrapulmonary metastases predominant in myxoid liposarcoma (11 of 13 patients; P &lt; 0·001).

Conclusion

Although histological subtype was not found to be an independent prognostic factor for oncological outcomes, the site of first metastasis differed significantly between subtypes.