Clinicopathological background of local recurrence in high grade sarcoma of the extremity with preoperative chemotherapy: A supplementary analysis of JCOG0304

Background The mainstay of treatment for soft-tissue sarcomas is complete resection with negative surgical margins. However, treatment strategies for local control including the frequency of adjuvant radiotherapy (RT) and surgical margin differ greatly between Japan and other countries, and the optimal strategy of local control remains controversial. Methods A total of 70 patients with high-grade sarcoma who underwent surgery of the 72 patients enrolled in JCOG0304, were included. The primary endpoint was the proportion of local recurrence, and we investigated the clinicopathological background of local recurrence cases, including the surgical margins according to the Japanese Orthopedic Association (JOA) margin classification or histological margin, and use of adjuvant RT. Results Local recurrence occurred in five patients, with a 5-year local recurrence proportion of 7.1% (95% confidence interval, 2.6%-14.8%) in 70 patients. The histological subtype were four cases of undifferentiated pleomorphic sarcoma (UPS) and 1 case of liposarcoma. The 5-year local recurrence proportions for UPS and non-UPS were 19.0% and 2.0%, respectively. Two of the five recurrent cases (40%) had adjuvant RT. The recurrent cases were four males and one female, median age 54 years (range: 33-66), JOA margin classification showed wide resection in four cases and marginal resection in one case, and histological margin showed negative in all five cases. Conclusion Despite the low proportion of adjuvant RT, local control of high-grade soft tissue sarcoma with preoperative chemotherapy in JCOG0304 was good. However, more detailed surgical margin evaluation and the use of adjuvant RT should be further investigated in the future for UPS.