Table 3 Predictive factors of ltPFS in patients with S-STM who underwent RISI

Gender

Male

1.0

Female

0.927(0.631–1.364)

0.702

Age (years)

< 60

1.0

≥ 60

1.302(0.885–1.914)

0.180

KPS

≥ 80

1.0

1.0

< 80

4.110(2.320–7.286)

< 0.001

2.391(1.302–4.394)

0.005

Primary tumor

Colorectal carcinoma

1.0

1.0

Lung carcinoma

1.510(0.887–2.571)

0.129

2.433(1.365–4.335)

0.003

Head-neck carcinoma

0.498(0.253–0.981)

0.044

1.409(0.657–3.022)

0.378

Gastric carcinoma

0.915(0.451–1.857)

0.806

1.781(0.840–3.775)

0.132

Skin and soft tissue carcinoma

2.442(1.157–5.156)

0.019

2.721(1.172–6.317)

0.020

Others ^a

0.665(0.398–1.111)

0.119

1.327(0.745–2.364)

0.337

Pathological grade

High-grade

1.0

1.0

Low-grade

1.544(1.025–2.325)

0.037

1.248(0.774–2.011)

0.364

Unknown

1.154(0.705–1.890)

0.569

0.808(0.470–1.389)

0.441

Number of metastases

1

1.0

1.0

≥ 2

2.030(1.364–3.021)

< 0.001

1.980(1.296–3.027)

0.002

Seed implantation site

Thoracic wall

1.0

Abdominal wall

1.339(0.472–3.802)

0.584

Head and neck

1.064(0.567–1.999)

0.846

Arms and legs

1.351(0.720–2.536)

0.349

Others ^b

0.833(0.389–1.784)

0.639

D90 (Gy)

< 120

1.0

1.0

≥ 120

0.306(0.208–0.451)

< 0.001

0.371(0.235–0.586)

< 0.001

Distance from skin (cm)^c

< 1

1.0

≥ 1

0.851(0.586–1.237)

0.398

Maximum diameter (cm)

≤ 3

1.0

1.0

3–5

1.72(1.083-2.745-)

0.022

0.800(0.429–1.493)

0.483

≥ 5

4.202(2.606–6.776)

< 0.001

1.381(0.635–3.008)

0.416

Clear boundary

No

1.0

1.0

Yes

0.258(0.170–0.390)

< 0.001

0.501(0.297–0.846)

0.010

Regular shape

No

1.0

1.0

Yes

0.357(0.239–0.533)

< 0.001

1.126(0.610–2.079)

0.704

Uniform density

No

1.0

1.0

Yes

0.309(0.205–0.464)

< 0.001

0.546(0.337–0.886)

0.014

Necrosis

No

1.0

1.0

Yes

2.927(1.823–4.701)

< 0.001

1.049(0.523–2.104)

0.893

Previous radiotherapy

No

1.0

Yes

1.491(0.777–2.860)

0.230

Previous chemotherapy

No

1.0

Yes

1.321(0.865–2.017)

0.198

Postoperative systemic therapy

No

1.0

Yes

1.056(0.688–1.621)

0.802