. 2024 Jul 30;115(10):3394–3402. doi: 10.1111/cas.16297

TABLE 3.

Univariate and multivariate analyses of factors affecting overall survival (OS) and progression‐free survival (PFS) in 23 patients receiving temozolomide (TMZ)‐containing chemotherapy for osteosarcoma with recurrence or progression (R/P).

Variable	Factor (n)	2‐year OS, % (95% CI)	Univariate analysis	Multivariate analysis		6‐month PFS, % (95% CI)	Univariate analysis	Multivariate analysis
Variable	Factor (n)	2‐year OS, % (95% CI)	p value	HR (95% CI)	p value	6‐month PFS, % (95% CI)	p value	HR (95% CI)	p value
Age group	0–19 years (17)	46.9 (20.7–69.5)	0.283	N.E.	N.E.	28.2 (9.6–50.5)	0.842	N.E.	N.E.
Age group	≥20 years (6)	83.3 (27.3–97.5)				50.0 (11.1–80.4)
Sex	Male (12)	55.6 (23.7–78.7)	0.672	N.E.	N.E.	41.7 (15.2–66.5)	0.807	N.E.	N.E.
Sex	Female (11)	59.7 (24.1–82.9)				24.2 (4.4–52.5)
First RFI	<18 months (11)	24.2 (3.8–54.2)	0.053	N.E.	N.E.	18.2 (2.9–44.2)	0.194	N.E.	N.E.
First RFI	≥18 months (12)	83.3 (48.2–95.6)				50.0 (20.8–73.6)
Primary tumor site	Extremity (20)	61.4 (35.2–79.6)	0.042	Reference		33.8 (14.4–54.4)	0.709	N.E.	N.E.
Primary tumor site	Axial (3)	33.3 (0.9–77.4)		3.77 (0.19–76.1)	0.386	33.3 (0.9–77.4)
R/P site	Lung alone (9)	76.2 (33.2–93.5)	0.438	N.E.	N.E.	44.4 (13.6–71.9)	0.590	N.E.	N.E.
	Local (1)	NA (NA–NA)				N.A. (N.A.–N.A.)
	Others (13)	46.2 (19.2–69.6)				23.1 (5.6–47.5)
Salvage chemotherapy after R/P	No (6)	33.3 (4.6–67.6)	0.672	N.E.	N.E.	16.7 (0.8–51.7)	0.108	N.E.	N.E.
Salvage chemotherapy after R/P	Yes (17)	67.9 (38.8–85.4)				40.3 (17.6–62.2)
Prior use of other alkylators	No (3)	33.3 (0.9–77.4)	0.773	N.E.	N.E.	N.A. (N.A.–N.A.)	0.245	N.E.	N.E.
Prior use of other alkylators	Yes (20)	61.9 (35.8–79.9)				39.4 (18.6–59.7)
Local treatment for primary site after R/P	No (20)	60.9 (34.8–79.3)	0.017	Reference		33.8 (14.4–54.4)	0.709	N.E.	N.E.
Local treatment for primary site after R/P	Yes (3)	33.3 (0.9–77.4)		16.7 (0.92–300.5)	0.057	33.3 (0.9–77.4)
Local treatment for metastasis after R/P	No (4)	N.A. (N.A.–N.A.)	0.007	Reference		N.A. (N.A.–N.A.)	0.366	N.E.	N.E.
Local treatment for metastasis after R/P	Yes (19)	66.2 (39.6–83.3)		0.11 (0.01–1.76)	0.119	36.8 (16.5–57.5)
Disease status before TMZ‐containing chemotherapy	Remission (9)	87.5 (38.7–98.1)	0.048	Reference		63.5 (23.8–86.6)	0.043	Reference
Disease status before TMZ‐containing chemotherapy	Nonremission (14)	37.0 (12.3–62.5)		5.26 (1.03–26.8)	0.046	14.3 (2.3–36.6)		5.98 (1.48–24.2)	0.012
MGMT protein expression	No/low (6)	83.3 (27.3–97.5)	0.356	Reference		66.7 (19.5–90.4)	0.022	Reference
MGMT protein expression	Intermediate/high (17)	50.7 (25.1–71.6)		2.96 (0.50–17.5)	0.232	23.5 (7.3–44.9)		8.69 (1.68–44.8)	0.010

Abbreviations: CI, confidence interval; HR, hazard ratio; MGMT, O‐6‐methylguanine‐DNA methyltransferase; N.A., not available; N.E., not evaluated; RFI, relapse‐free interval.