Neoadjuvant radiation improves margin-negative resection rates in extremity sarcoma but not survival

[Predictive factors assessment of pathological response to neoadjuvant radiotherapy of soft tissue sarcomas]

PURPOSE

Conserving surgery combined with radiotherapy in presence of local recurrence risk factors is standard treatment of soft tissue sarcomas, a group of rare and heterogeneous tumours. Radiotherapy is performed before or after surgery. In neoadjuvant setting, late radiation-induced toxicity is reduced and pathological response to radiotherapy could be achieved. A complete pathological response to radiotherapy has recently been shown to predict better survival. Our study aims at identifying predictive factors of pathological response to neoadjuvant radiotherapy (clinical, radiological or histological) of soft tissue sarcomas.

PATIENTS AND METHODS

Clinical, imaging (MRI: perilesional oedema, necrosis, tumour heterogeneity, vasculonervous relationships) and pathological (pathological subtype, tumour grade, anticipated/obtained resection quality) data were retrospectively collected. Tumour response (imaging and pathological), patient outcome, acute and late radiation-induced toxicity, predictive factors of pathological response to neoadjuvant radiotherapy were studied. The 2-test or exact-Fisher test (qualitative variables) and by Student's t-test or Kruskal-Wallis test (quantitative variables) were used for statistical analysis.

RESULTS

From April 2017 to April 2021, neoadjuvant radiotherapy (50Gy in 25 fractions) followed by surgical excision was performed to 36 consecutive patients with liposarcomas (n=17/36), or undifferentiated sarcomas (n=8/36). MRI response was complete in 1 patient, partial in 9 patients (n=9/36, 25%), stable in 21 patients (n=21/36, 58%) or in progression in 5 patients (n=5/36, 14%). Pathological response was observed in 22 patients (61%). No grade 3-4 acute radiation-induced toxicity was observed. Regarding late toxicity, 28% of patients had grade 1-2 oedema (n=10/36), 39% had a grade 1 fibrosis (n=14/36), and 30% grade 1 pain (n=11/36). No predictive factors of response to radiotherapy was statistically significant.

CONCLUSIONS

Neoadjuvant radiotherapy is well-tolerated. No clinical, radiological or pathological predictive factors was identified for radiotherapy tumour response.

Re-excision After Unplanned Excision of Soft Tissue Sarcoma is Associated with High Morbidity and Limited Pathologic Identification of Residual Disease

BACKGROUND

Patients with unplanned excision (UPE) of trunk and extremity soft tissue sarcoma (STS) present a significant management challenge for sarcoma specialists. Oncologic re-resection has been considered standard practice after UPE with positive or uncertain margins. A strategy of active surveillance or "watch and wait" has been suggested as a safe alternative to routine re-excision. In this context, the current study sought to evaluate short-term outcomes and morbidity after re-resection to better understand the risks and benefits of this treatment strategy.

METHODS

A retrospective, single-institution study reviewed patients undergoing oncologic re-resection after UPE of an STS during a 5-year period (2015-2020), excluding those with evidence of gross residual disease. Short-term clinical outcomes were evaluated together with final pathologic findings.

RESULTS

The review identified 67 patients undergoing re-resection after UPE of an STS. Of these 67 patients, 45 (67%) were treated with a combination of external beam radiation therapy (EBRT) and surgery. Plastic surgery was involved for reconstruction in 49 cases (73%). The rate of wound complications after re-resection was 45 % (n = 30), with 15 % (n = 10) of the patients experiencing a major wound complication. Radiation therapy and plastic surgery involvement were independently associated with wound complications. Notably, 45 patients (67%) had no evidence of residual disease in the re-resection specimen, whereas 13 patients (19 %) had microscopic disease, and 9 patients (13%) had indeterminate pathology.

CONCLUSION

Given the morbidity of re-resection and limited identification of residual disease, treatment plans and discussions with patients should outline the expected pathologic findings and morbidity of surgery.

Radiation Therapy for Soft Tissue Sarcoma

Radiation therapy is an integral component of local management with oncologic resection for soft tissue sarcoma. Radiotherapy is indicated in patients at an increased risk of local recurrence so that improved local control may be achieved. Sequencing of radiotherapy and resection should be determined by multidisciplinary input before treatment initiation. For most patients, preoperative delivery of radiation therapy is preferred. In patients initially thought to be at low risk for local recurrence and found to have unexpected adverse pathologic features at resection, postoperative radiation therapy is indicated. The use of radiation therapy for retroperitoneal sarcoma is controversial; when used, preoperative delivery of radiation is recommended.

Preoperative versus Post-operative Radiotherapy for Extremity Soft tissue Sarcoma: a Systematic Review and Meta-analysis of Long-term Survival

BACKGROUND

The role of perioperative radiotherapy in the management of resectable extremity soft tissue sarcoma (ESTS) is widely recognised for local tumour control, wound complications (WC) and long-term function. However, debate continues regarding its implications on long-term survival. This study aimed to determine whether the timing of perioperative radiotherapy affects long-term survival outcomes in adults with ESTS.

METHODS

A systematic literature search of MEDLINE, EMBASE, Web of Science and Cochrane was performed. The primary outcome measure was the pooled hazard ratio (HR) at 95% confidence intervals. Secondary outcomes and subgroup analyses were presented as cumulative odds ratios (OR). A random-effects, generic inverse variance method and sensitivity analysis were performed to minimise heterogeneity.

RESULTS

Six studies (n = 4192 patients) were identified. Time-to-event analysis demonstrated a statistically significant advantage in post-operative radiotherapy for overall survival (HR 1.15 and p = 0.05). Combined HRs for disease-free (1.25 and p = 0.22) and disease-specific (1.06 and p = 0.43) survival also favoured post-operative radiotherapy but did not achieve statistical significance. Post-operative radiotherapy was shown to confer an overall (OR 1.19 and p = 0.01), disease-free (OR 1.19 and p = 0.01) and disease-specific (OR 1.19 and p = 0.01) survival advantage on subgroup analysis. This survival benefit was best observed at three years in the disease-free survival comparison (OR 1.55 and p = 0.003). Preoperative radiotherapy was associated with more WC (OR 2.74 and p<0.00001).

CONCLUSIONS

Pooled analysis of published literature suggests that post-operative radiotherapy confers a significant long-term survival advantage with fewer WC. Further large multicentre randomised controlled trials with long-term follow-up are required to determine the optimal perioperative radiotherapy regime in adult ESTS.

Assessment of Resection Margins in Bone Tumor Surgery

Limb salvage surgery is now the preferred procedure for bone tumor surgery. To decrease the risk of local recurrence, it is crucial to obtain adequate resection margins. The obtained margins must be evaluated postoperatively because they influence what treatment is given subsequently when margins are not adequate (e.g., surgical revision and radiotherapy). The study aims to evaluate margin assessment of tumor specimen by MRI compared to conventional histology (to establish the viability of using MRI) and assess the accuracy of a patient-specific instrument when narrow margins were aimed. The resection margins in 12 consecutive patients that were operated on for bone tumor resection were prospectively analyzed using three methods: MRI of the resection specimen, macroscopic evaluation of specimen slices, and microscopic pathological evaluation. The assessments were qualitative (R0, R1, and R2) and quantitative (distance in mm). MRI, macroscopic, and microscopic margins generated similar results for both the qualitative (all resections were R0) and quantitative assessments. The median error in safe margins was 2 mm with a surgical guide (PSI) and 5 mm without a surgical guide. Local recurrences were not detected after a mean follow-up period of 3.7 years (range, 2.1-5 years); however, four patients died during the study. In conclusion, MRI is a valuable tool for assessing safe margins. When specimens are not available for pathological assessment (e.g., extracorporeally irradiated autograft or autoclaved autograft), MRI could be used to evaluate margins. In particular, when tumor volume is high, MRI could also help to focus the pathological examination on areas of concern.

Pre- or postoperative radiotherapy for soft tissue sarcomas

Sarcomas are rare tumours arising from mesenchymal tissue. A multimodal management in an expert centre combining surgery and radiotherapy is the current standard of care for localized soft-tissue sarcomas of the extremities, to enable limb-sparing strategies. The delivery of pre- radiotherapy or postoperative radiotherapy offers similar local control and survival rates but the toxicity profile is quite different: preoperative radiotherapy increases the risk of wound complications and postoperative radiotherapy affects long-term functional outcomes. While postoperative radiotherapy has long been the rule, especially in Europe, technical improvements with image-guided- and intensity-modulated radiotherapy associated with a better management of postoperative wounds has tended to change practices with more frequent preoperative radiotherapy. More recently the possibilities of a hypofractionated regimen or potentiation by nanoparticles to increase the therapeutic index plead in favour of a preoperative delivery of radiotherapy. The aim of this paper is to report pros and cons of pre- and post-operative radiotherapy for soft-tissue sarcomas.