Study protocol: randomized phase III trial of neo-adjuvant and adjuvant chemotherapy vs. immediate surgery and adjuvant chemotherapy for localized soft tissue sarcoma: Japan Clinical Oncology Group study JCOG2102 (NACLESS).

The optimal timing of surgery and the number of courses of perioperative chemotherapy for high-risk soft tissue sarcoma patients are still controversial. Tumour growth during neoadjuvant chemotherapy led to limb amputation in some patients. This study aims to confirm the non-inferiority of surgery and three courses of adjuvant chemotherapy with adriamycin (30 mg/m2, days 1 and 2) plus ifosfamide (2 g/m2, days 1-5) compared with our standard treatment of three courses of neoadjuvant chemotherapy and surgery followed by two courses of adjuvant chemotherapy with adriamycin plus ifosfamide for localized high-risk soft tissue sarcoma patients. This is a multi-center, two-arm, open-label, randomized phase III trial. The primary aim is to confirm the non-inferiority in overall survival (margin: hazard ratio of 1.61). This is the first randomized controlled trial to compare neoadjuvant chemotherapy and immediate surgery for soft tissue sarcoma. This trial was initiated on 16 November 2022 and registered with the Japan Clinical Trials Registry (jRCTs031220446).