Optimization of the Therapeutic Approach to Patients with Sarcoma: Delphi Consensus

Case Report: Adjuvant image-guided radiation therapy reduces surgical invasiveness in malignant peripheral nerve sheath tumors

Introduction

Malignant peripheral nerve sheath tumors (MPNSTs) are a group of rare soft tissue sarcomas of mesenchymal origin. These tumors generally require extensive local excision owing to their aggressive potential. Though the role of radiotherapy is controversial, in this report, we present the case of an MPNST in the forearm that was treated with microsurgery followed by image-guided radiation therapy to achieve complete tumor disappearance at the 18-month follow-up.

Case report

A 69-year-old woman with underlying paranoid schizophrenia was referred to our department with pain, severe swelling, and ecchymosis of her right forearm. Physical examination showed hypoesthesia in the segments innervated by the median nerve and reduced motor strength of her right hand. A gadolinium-enhanced MRI showed a large malignant peripheral nerve sheath tumor (13 x 8 x 7 cm) of the median nerve in the forearm. She underwent microsurgical en-bloc tumor resection with sparing of the median nerve. Thirty-five days postoperatively, she underwent image-guided radiotherapy (IGRT) using volumetric modulated arc therapy (VMAT). Serial MRI scans of the forearm with Gadolinium and whole-body CT scan with contrast enhancement at 30 days, 6 months, 1 year, and 18 months postoperatively documented no tumor recurrence, remnants, or metastases.

Conclusions

In this report, we demonstrate the successful use of advanced radiotherapy techniques such as IGRT while avoiding demolitive surgery for MPNST. Though a longer follow-up is necessary, at the 18-month follow-up, the patient demonstrated good outcomes from surgical resection followed by adjuvant RT for MPNST in the forearm.

Combining a Customized Immobilization System with an Innovative Use of the ExacTrac System for Precise Volumetric Modulated Arc Therapy of Challenging Forearm Sarcomas

High-precision image-guided radiation therapy (RT) for tumors abutting the appendicular skeleton may mean technical difficulties and concerns among practitioners. This technical note addresses the specific challenge for normofractionated image-guided RT of a tumor target in a forearm through an unconventional use of a treatment verification system usually devoted to stereotactic RT.

Canadian consensus on TRK-inhibitor therapy for NTRK fusion-positive sarcoma

Malignant sarcomas are rare accounting for <1% of all adult solid malignancies and approximately 11% to 13% of all pediatric malignancies. TRK-inhibitors have demonstrated robust and long-lasting responses in patients with NTRK fusion-positive solid tumors, including sarcoma. Access to these agents in many jurisdictions such as Canada remains limited. We undertook a modified Delphi consensus to articulate and convey the clinical importance of these agents for the Canadian sarcoma community. A systematic search of published and presented literature was conducted to identify clinical trials reporting outcomes on the use of TRK-inhibitors in relapsed/refractory NTRK fusion-positive sarcoma. Three main consensus questions were identified: (a) is there currently an unmet clinical need for systemic therapy options in relapsed/refractory sarcoma? (b) do TRK-inhibitors confer a clinical benefit to patients with NTRK fusion-positive sarcoma? (c) do phase I/II basket trials provide sufficient evidence to justify funding of TRK-inhibitors in NTRK fusion-positive sarcoma? Response rates to the first and second surveys were 57% (n = 30) and 42% (n = 22), respectively. There was strong agreement among the Canadian sarcoma community that there was unmet clinical need for effective systemic therapy options in relapsed/refractory sarcoma, that TRK-inhibitors are a safe and effective treatment option for patients with NTRK fusion-positive sarcoma, and that available phase I/II basket trials provide sufficient evidence to support funding of these agents in relapsed/refractory NTRK fusion-positive sarcoma. TRK-inhibitors are a safe and effective systemic therapy option for patients with relapsed/refractory NTRK fusion-positive sarcoma.