Clinical application of sandwich-based iodine-125 seed brachytherapy for adjuvant management of intraoperatively planned positive margins in malignant tumors involving soft tissue

doi:10.3969/j.issn.1674-8115.2026.10.015

Abstract

Abstract:

Objective ·To evaluate the safety and short-term clinical efficacy of iodine-125 (I-125) seed brachytherapy for adjuvant management of intraoperatively planned positive margins (PPMs) in malignant tumors involving soft tissue. Methods ·This retrospective study included 25 patients who underwent tumor resection and received adjuvant brachytherapy using the sandwich-based I-125 seed implantation for PPMs in the Department of Bone Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, between June 2020 and June 2022. According to tumor status at the time of surgery, the patients were divided into the primary group (n=16) and the recurrent group (n=9). Demographic data (age and gender), tumor-related characteristics (tumor location, tumor size, pathological type, and type of positive margin), treatment-related characteristics (postoperative adjuvant therapy), and follow-up data (follow-up duration, local control status, and treatment-related complications) of the two groups were collected and analyzed. The primary outcome was the local control (LC) rate, and the secondary outcome was treatment-related complications. Local control and treatment safety were compared between the two groups. Results ·Among the 25 patients, 19 were males and 6 were females, with a mean age of (60.9±5.8) years. Tumors were located in the pelvis (n=8), upper extremities (n=6), and lower extremities (n=11). The predominant pathological types were liposarcoma (n=7), undifferentiated pleomorphic sarcoma (n=5), and rhabdomyosarcoma (n=3). PPM types included margins adjacent to nerves (n=11), blood vessels (n=6), bone interfaces (n=4), and visceral organs (n=4). All patients completed follow-up, with a mean follow-up duration of [20.00 (14.00, 25.00)] months and a follow-up rate of 100%. Among them, 17 patients received no postoperative adjuvant therapy, whereas 8 patients received postoperative adjuvant therapy, including chemotherapy (n=5), radiotherapy (n=1), chemoradiotherapy (n=1), and targeted therapy combined with immunotherapy (n=1). During the follow-up period, local recurrence occurred in 5 patients, resulting in an overall LC rate of 80.0% (20/25). The LC rate was 81.3% (13/16) in the primary group and 77.8% (7/9) in the recurrent group, with no significant difference between the two groups (P=1.000). Treatment-related complications occurred in 4 patients (16.0%), including delayed wound healing in 3 patients and delayed-onset common peroneal nerve injury in 1 patient. Conclusion ·I-125 seed brachytherapy can be used as an adjuvant treatment for PPMs in malignant tumors involving soft tissue, providing favorable local control with a relatively low incidence of treatment-related complications.

Key words: malignant tumors involving soft tissue, brachytherapy, planned positive margin (PPM), local recurrence

CLC Number:

R730.55

Zhang Peng, Chen Wenyong, Liu Lei, Zuo Dongqing, Cai Zhengdong, Sun Wei. Clinical application of sandwich-based iodine-125 seed brachytherapy for adjuvant management of intraoperatively planned positive margins in malignant tumors involving soft tissue[J]. Journal of Shanghai Jiao Tong University (Medical Science), 2026,(10): 1442-1448.

Figures/Tables 5

TrendMD

References 13

[1]	Beane J D, Yang J C, White D, et al. Efficacy of adjuvant radiation therapy in the treatment of soft tissue sarcoma of the extremity: 20-year follow-up of a randomized prospective trial[J]. Ann Surg Oncol, 2014, 21(8): 2484-2489.
[2]	Daigeler A, Zmarsly I, Hirsch T, et al. Long-term outcome after local recurrence of soft tissue sarcoma: a retrospective analysis of factors predictive of survival in 135 patients with locally recurrent soft tissue sarcoma[J]. Br J Cancer, 2014, 110(6): 1456-1464.
[3]	Fujiwara T, Sumathi V, Parry M, et al. The role of surgical margin quality in myxofibrosarcoma and undifferentiated pleomorphic sarcoma[J]. Eur J Surg Oncol, 2021, 47(7): 1756-1762.
[4]	Erol B, Baysal Ö. Does unplanned soft tissue sarcoma surgery have a negative effect on prognosis?[J]. J Invest Surg, 2022, 35(1): 38-43.
[5]	Ji Z, Jiang Y L, Tian S Q, et al. The effectiveness and prognostic factors of CT-guided radioactive I-125 seed implantation for the treatment of recurrent head and neck cancer after external beam radiation therapy[J]. Int J Radiat Oncol Biol Phys, 2019, 103(3): 638-645.
[6]	Wang C R, Chen Z Q, Sun W, et al. Palliative treatment of pelvic bone tumors using radioiodine (¹²⁵I) brachytherapy[J]. World J Surg Oncol, 2016, 14(1): 294.
[7]	WHO Classification of Tumours Editorial Board. Soft tissue and bone tumours[M]. 5th ed. Lyon: International Agency for Research on Cancer, 2020.
[8]	Oken M M, Creech R H, Tormey D C, et al. Toxicity and response criteria of the eastern cooperative oncology group[J]. Am J Clin Oncol, 1982, 5(6): 649-655.
[9]	Assayag J, Kim C, Chu H T, et al. The prognostic value of Eastern Cooperative Oncology Group performance status on overall survival among patients with metastatic prostate cancer: a systematic review and meta-analysis[J]. Front Oncol, 2023, 13: 1194718.
[10]	Kask G, Repo J P, Tukiainen E J, et al. Soft tissue sarcoma of lower extremity: functional outcome and quality of life[J]. Ann Surg Oncol, 2021, 28(11): 6892-6905.
[11]	Yang J C, Chang A E, Baker A R, et al. Randomized prospective study of the benefit of adjuvant radiation therapy in the treatment of soft tissue sarcomas of the extremity[J]. J Clin Oncol, 1998, 16(1): 197-203.
[12]	Mo Z Q, Zhang T, Zhang Y L, et al. Feasibility and clinical value of CT-guided ¹²⁵I brachytherapy for metastatic soft tissue sarcoma after first-line chemotherapy failure[J]. Eur Radiol, 2018, 28(3): 1194-1203.
[13]	Fairweather M, Wang J P, Devlin P M, et al. Safety and efficacy of radiation dose delivered via iodine-125 brachytherapy mesh implantation for deep cavity sarcomas[J]. Ann Surg Oncol, 2015, 22(5): 1455-1463.

Item	Total (n=25)	Primary group (n=16)	Recurrent group (n=9)
Demographic data
Gender/n(%)
Male	19 (76.0)	11 (68.8)	8 (88.9)
Female	6 (24.0)	5 (31.3)	1 (11.1)
Age/year	60.9±5.8	63.3±5.0	56.6±4.5
Tumor-related characteristics
Tumor location/n(%)
Pelvis	8 (32.0)	5 (31.3)	3 (33.3)
Upper extremities	6 (24.0)	4 (25.0)	2 (22.2)
Lower extremities	11 (44.0)	7 (43.8)	4 (44.4)
Tumor size/n(%)
≥5 cm	16 (64.0)	8 (50.0)	8 (88.9)
＜5 cm	9 (36.0)	8 (50.0)	1 (11.1)
Type of positive margin/n(%)
Adjacent to nerves	11 (44.0)	7 (43.8)	4 (44.4)
Adjacent to blood vessels	6 (24.0)	4 (25.0)	2 (22.2)
Adjacent to bone interfaces	4 (16.0)	3 (18.8)	1 (11.1)
Adjacent to visceral organs	4 (16.0)	2 (12.5)	2 (22.2)
Pathological type/n(%)
Undifferentiated pleomorphic sarcoma	5 (20.0)	5 (31.3)	0 (0)
Rhabdomyosarcoma	3 (12.0)	0 (0)	3 (33.3)
Squamous cell carcinoma	2 (8.0)	2 (12.5)	0 (0)
Soft tissue metastasis	1 (4.0)	1 (6.3)	0 (0)
Melanoma	1 (4.0)	0 (0)	1 (11.1)
Liposarcoma	7 (28.0)	5 (31.3)	2 (22.2)
Synovial sarcoma	1 (4.0)	0 (0)	1 (11.1)
Others	5 (20.0)	3 (18.8)	2 (22.2)

Item	Total (n=25)	Primary group (n=16)	Recurrent group (n=9)
Demographic data
Gender/n(%)
Male	19 (76.0)	11 (68.8)	8 (88.9)
Female	6 (24.0)	5 (31.3)	1 (11.1)
Age/year	60.9±5.8	63.3±5.0	56.6±4.5
Tumor-related characteristics
Tumor location/n(%)
Pelvis	8 (32.0)	5 (31.3)	3 (33.3)
Upper extremities	6 (24.0)	4 (25.0)	2 (22.2)
Lower extremities	11 (44.0)	7 (43.8)	4 (44.4)
Tumor size/n(%)
≥5 cm	16 (64.0)	8 (50.0)	8 (88.9)
＜5 cm	9 (36.0)	8 (50.0)	1 (11.1)
Type of positive margin/n(%)
Adjacent to nerves	11 (44.0)	7 (43.8)	4 (44.4)
Adjacent to blood vessels	6 (24.0)	4 (25.0)	2 (22.2)
Adjacent to bone interfaces	4 (16.0)	3 (18.8)	1 (11.1)
Adjacent to visceral organs	4 (16.0)	2 (12.5)	2 (22.2)
Pathological type/n(%)
Undifferentiated pleomorphic sarcoma	5 (20.0)	5 (31.3)	0 (0)
Rhabdomyosarcoma	3 (12.0)	0 (0)	3 (33.3)
Squamous cell carcinoma	2 (8.0)	2 (12.5)	0 (0)
Soft tissue metastasis	1 (4.0)	1 (6.3)	0 (0)
Melanoma	1 (4.0)	0 (0)	1 (11.1)
Liposarcoma	7 (28.0)	5 (31.3)	2 (22.2)
Synovial sarcoma	1 (4.0)	0 (0)	1 (11.1)
Others	5 (20.0)	3 (18.8)	2 (22.2)

Item	Total (n=25)	Primary group (n=16)	Recurrent group (n=9)
Postoperative adjuvant therapy/n(%)
Chemotherapy	5 (20.0)	3 (18.8)	2 (22.2)
Radiotherapy	1 (4.0)	0 (0)	1 (11.1)
Chemoradiotherapy	1 (4.0)	1 (6.3)	0 (0)
Targeted therapy combined with immunotherapy	1 (4.0)	1 (6.3)	0 (0)
None	17 (68.0)	11 (68.8)	6 (66.7)
Follow-up duration/month	20.00 (14.00, 25.00)	18.50 (13.25, 25.00)	21.00 (18.00, 24.00)
LC rate/n(%)	20 (80.0)	13 (81.3)	7 (77.8)
Treatment-related complications/n(%)
Delayed wound healing	3 (12.0)	2 (12.5)	1 (11.1)
Nerve injury	1 (4.0)	0 (0)	1 (11.1)
Other adverse events related to iodine-125 seed implantation	0 (0)	0 (0)	0 (0)

Item	Total (n=25)	Primary group (n=16)	Recurrent group (n=9)
Postoperative adjuvant therapy/n(%)
Chemotherapy	5 (20.0)	3 (18.8)	2 (22.2)
Radiotherapy	1 (4.0)	0 (0)	1 (11.1)
Chemoradiotherapy	1 (4.0)	1 (6.3)	0 (0)
Targeted therapy combined with immunotherapy	1 (4.0)	1 (6.3)	0 (0)
None	17 (68.0)	11 (68.8)	6 (66.7)
Follow-up duration/month	20.00 (14.00, 25.00)	18.50 (13.25, 25.00)	21.00 (18.00, 24.00)
LC rate/n(%)	20 (80.0)	13 (81.3)	7 (77.8)
Treatment-related complications/n(%)
Delayed wound healing	3 (12.0)	2 (12.5)	1 (11.1)
Nerve injury	1 (4.0)	0 (0)	1 (11.1)
Other adverse events related to iodine-125 seed implantation	0 (0)	0 (0)	0 (0)