Risk of Malignant Transformation of Giant Cell Tumors of Bone Is 8 Times Lower with Megavoltage vs. Orthovoltage Radiation Therapy

Table 2

Details of malignant/sarcomatous transformation and local recurrence for each study.

First author (year)	No. of tumors	Mean (range) follow-up, yr	Malignant/sarcomatous transformation (n)	Mean (range) time to transformation, yr	Local recurrence (n)	Mean (range) time tolocal recurrence, yr
Megavoltage
Chakravati [8] (1999)	20	9.3 (NA)	0		3	0.69 (0.4–1)
Bell [9] (1983)	15	12 (2–25)	1	21 (NA)	1	2 (NA)
Bennett [10] (1993)	16	9 (NA)	0		4	15 (0.7–2.1)
Sharma [11] (1990)	30	9.2 (NA)	0		2	7.7 (7–8.3)
Daugaard [12] (1987)	8	6.5 (NA)	0		1	0.7 (NA)
Feigenberg [13] (2003)	26	12 (2.4–26)	1	22 (NA)	6	1.2 (1.1–1.7)
Shi [14] (2013)	34	17 (1.4–34)	1	4.3 (NA)	6	1.9 (0.1–4.4)
Malone [15] (1995)	21	15 (2–35)	0		2	2.5 (1–4)
Ruka [16] (2010)	77	4.8 (0.5–33)	2	4 (3.4–4.6)	12	2.3 (0.3–6.3)
Nair [3] (1999)	20	5.3 (NA)	0		2	1.3 (1.1–1.5)
Bhatia [17] (2011)	58	8 (4–28)	0		8	∼2.5 (NA)
Caudell [4] (2003)	25	10 (NA)	2	11.5 (11–12)	10	0.9 (NA)
Khan [18] (1999)	6	13 (NA)	0		1	3 (NA)
Schwartz [19] (1989)	13	6.5 (1.5–13)	0		2	0.7 (0.4–1)
Seider [20] (1986)	9	11 (NA)	0		3	2.7 (0.5–6)
Roeder [21] (2010)	5	4.9 (NA)	0		1	0.25 (NA)
Walter [22] (1960)	4	2.6 (2–4)	0		1	0.5 (NA)
JHH	6	14 (10–21)	0		1	0.3 (NA)
Orthovoltage
Mnaymneh [23] (1964)	16	31 (12–44)	2	3.4 (1.7–5)	14	2.4 (0.2–5)
Walter [22] (1960)	12	8.2 (2–20)	0		2	1 (0.5–1.5)
Dahlin [24] (1970)	36	NA	11	9 (3.7–38)	17	<3 (NA)
Bradshaw [25] (1964)	50	>5 (NA)	4	NA (1.5–8.5)	16	NA
Windeyer [26] (1949)	29	NA	2	NA	4	NA
McGrath [27] (1972)	21	NA	5	10 (1–17)	8	NA
Seider [20] (1986)	2	24 (18–30)	0	0	0
Daugaard [12] (1987)	2	12 (8–16)	0	0	2	1 (0.2–1.8)

JHH, Johns Hopkins Hospital patients; NA, not available. Expressed as median (range).