Pre- or postoperative radiotherapy for soft tissue sarcomas

What is the optimal (neo)adjuvant strategy of extremity high-risk soft tissue sarcomas (ESTS)?

Currently, the standard treatment for extremity high-risk soft tissue sarcomas (ESTS) combines surgery and pre- or post-op radiation therapy (RT). In some selected cases, chemotherapy (CT) is incorporated into the therapeutic algorithm as a neoadjuvant approach to enable conservative management. Given the risk of local or metastatic relapse, this paper discusses the potential benefits of CT and RT in high-grade ESTs. The role of adjuvant chemotherapy in addition to neoadjuvant CT, the prognostic value of the pathological response to neoadjuvant treatment, and the role for an adjuvant "boost" following resection after pre-operative radiotherapy will be discussed.

[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.

Two Different Types of Sarcoma Occurring Synchronously: The Impact of Molecular Biology on Therapeutic Strategy

Sarcoma is a rare type of tumor that can arise in the different types of connective tissues. Symptoms vary depending on the size, type, and location of the tumor. Management and surgery should be performed in a referral sarcoma center with a molecular biology platform and a dedicated medical staff. A preoperative percutaneous core needle biopsy (CNB) is required to tailor the medical and surgical strategies. In this report, we describe the case of a well-differentiated retroperitoneal liposarcoma (WD LPS) discovered in the context of recurrent cystitis on an abdominal CT scan, synchronously occurring, with another different type of sarcoma, undifferentiated pleomorphic sarcoma (UPS) developing in the thigh, discovered because of sciatic pain. This extremely rare condition was confirmed by the molecular analysis and justifies a specific strategy taking account of the differential risk. This event should also encourage genetic counseling.

Conformal radiotherapy in management of soft tissue sarcoma in adults

We present the update of the recommendations of the French society of radiation oncology on soft tissue sarcomas. Currently, the initial management of sarcomas is very important as it may impact on patients' quality of life, especially in limb soft tissue sarcomas, and on overall survival in trunk sarcomas. Radiotherapy has to be discussed within a multidisciplinary board meeting with results of biopsy, eventually reexamined by a dedicated sarcoma pathologist. The role of radiotherapy varies according to localization of soft tissue sarcoma. It is part of the standard treatment in grade 2 and 3 sarcomas of the extremities and superficial trunk>5cm. In case of R1 or R2 resection, reexcision should be discussed. In such cases, it may be delivered preoperatively (50Gy/25 fractions of 2Gy) or postoperatively. In retroperitoneal sarcomas, preoperative conformal radiotherapy with or without modulated intensity cannot be proposed systematically in daily practice. Concomitant chemoradiotherapy cannot be considered a standard treatment. Intensity-modulated radiotherapy has become widely available. Other soft tissue sarcoma sites such as trunk, head and neck and gynaecological soft tissue sarcomas will be addressed, as well as other techniques that may be used such as brachytherapy and proton therapy.

[Preoperative versus postoperative radiotherapy in soft tissue sarcomas: State of the art and perspectives]

Radiation therapy is a standard treatment for limbs soft tissue sarcomas. Preoperative versus postoperative radiotherapy has been a controversial topic for years. With preoperative irradiation, the treatment volume is more limited, the delivered dose possibly lower and the tumor volume easier to delimit. Only one randomized trial compared these two irradiation sequences. The results in terms of local control and survival were equivalent but the risk of acute postoperative complications was higher if irradiation was administered before surgery. However, in the latest update of this trial, patients who received adjuvant irradiation exhibited more severe late toxicity than those treated preoperatively. In addition, with modern irradiation techniques such as conformal with image-guided intensity modulated radiotherapy and flap coverage techniques, the incidence of complications after preoperative irradiation were lower than historically published rates. Locally advanced proximal sarcomas and the failure of other neoadjuvant treatments are nowadays classical indications for preoperative irradiation. As with other neoadjuvant treatments, induction radiotherapy must be personalized according to the histological subtype, the tumor site and the benefit/risk ratio, which is best appreciated by a multidisciplinary surgical and oncological team in a specialized center in the management of soft-tissue sarcomas.

[Rôle of radiotherapy for sarcomas]

The quality of the initial management of sarcomas is fundamental because it conditions the patient's quality of life and his overall survival. Radiotherapy should be discussed in a multidisciplinary consultation meeting within the framework of the Netsarc+network. The place of radiotherapy in patients with soft tissue or bone sarcoma depends on the histology and tumour location, knowing that it is most often associated with surgery which remains the main treatment. It is part of the standard treatment for grade II and III deep limb sarcomas of 5cm or greater in size and Ewing's sarcomas. In these indications, conformal radiotherapy with modulation of intensity is used routinely, in combination with IGRT. In other locations, such as retroperitoneal sarcomas or uterine sarcomas, radiotherapy is not a standard of care and must be discussed according to the prognostic criteria related to the patient, the tumour, and the previously received treatments. New techniques, such as proton therapy, hadron therapy (carbon ions) are techniques particularly suited to bone sarcomas considered to be radioresistant. However, large prospective trials are lacking in these rare indications, explaining the lack of recommendations of a high level of evidence.