(P 209) THE OUTCOME OF R1 EXCISION COMBINED WITH ADJUVANT RADIOTHERAPY FOR SOFT TISSUE SARCOMA IN ELDERLY PATIENTS

Author(s)

SY

Shinichirou Yoshida, MD, PhD

Assistant professor
Department of Orthopaedic Surgery Tohoku University Graduate School of Medicine
Sendai, Miyagi, Japan

Co-Author(s)

jun iwatsu, MD

Department of Orthopaedic Surgery
Tohoku University Graduate School of Medicine
Sendai, Miyagi, Japan
Mnenori Watanuki, MD, PhD

part-time assistant professor
Department of Orthopaedic Surgery Tohoku University Graduate School of Medicine
Sendai, Miyagi, Japan
SH

Shin Hitachi, N/A, MD,PhD

Tohoku University School of Medicine
Sendai, Miyagi, Japan
MW

Mika Watanabe, N/A, MD,PhD

Tohoku Kosai Hospital
Sendai, Miyagi, Japan
TA

Toshimi Aizawa, N/A, MD,PhD

Tohoku University School of Medicine
Sendai, Miyagi, Japan

Objective: The main treatment modality for soft tissue sarcoma is surgical excision with wide margin (R0). However, it can cause loss of function because a lot of normal tissues are excised with tumor. Especially in elderly patients, marginal excision (R1) combined with adjuvant radiotherapy (RT) can be selected to prevent the loss of function. Here we report the outcome of R1 resection combined with adjuvant RT for elderly soft tissue sarcoma.

Methods: Of the 81 cases of soft tissue sarcoma older than 70 years who underwent surgery at our hospital from 2005 to 2021, 63 cases were included. These were divided into a group in which only R0 excision was performed (R0 group, 49 cases) and a group in which R1 excision was performed in combination with RT (RT + R1 group, 14 cases). Kaplan-Meier method, log-rank test and Cox proportional hazard model analysis were performed.

Results: The average age was 78 years, the average follow-up period was 36 months, and the average irradiation dose in the RT + R1 group was 58.4 Gy. The main histological subtypes are undifferentiated polymorphic sarcoma in 15 cases, myxofibrosarcoma in 15 cases, polymorphic liposarcoma in 8 cases, malignant peripheral nerve sheath tumor in 6 cases, leiomyosarcoma in 6 cases, and myxoid liposarcoma in 5 cases. Chemotherapy was performed in 6 patients (12%) in the R0 group and 4 patients (28%) in the RT + R1 group. Local recurrence was 5 cases (10%) in the R0 group and 1 case (7%) in the RT + R1 group. There were 12 (24%) distant metastases in the R0 group and 6 (42%) in the RT + R1 group. Dead of disease was 4 cases in both groups. The 5-year local control rate by the Kaplan-Meier method was 86.1% in the R0 group and 90.9% in the RT + R1 group (p = 0.716). The 5-year overall survival was 88.7% in the R0 group and 67.1% in the RT + R1 group (p = 0.072). RT + R1 resection was a significant poor prognosis factor in Cox proportional hazards model analysis.

Conclusion: R1 excision combined with adjuvant RT for elderly soft tissue sarcoma was capable of local control equivalent to R0 excision, but had a poorer prognosis than R0 resection.