Table 2

Distribution of local relapses according to biologically effective radiation dose*

All patients (n = 206)

Tumors ≥ 5 cm (n = 59)


Radiation dose (Gy)

Number of patients

Local relapse (%)

Number of patients

Local relapse (%)


No RT**

5

4 (80%)

1

1 (100%)

<30

25

2 (8%)

2

0

≥ 30 – <40

55

5 (9%)

17

3 (18%)

≥ 40 – <50

65

8 (12%)

15

3 (20%)

≥ 50

56

8 (13%)

24

4 (17%)


RT: radiation therapy

*biologically effective dose (BED) according to the linear-quadratic model.13

BED = nd(1+ [d÷α/β]) where n = number of fractions, d = dose per fraction, and α/β = 10 for plasmacytoma.

**All patients treated with surgery alone (with chemotherapy in one).

Knobel et al. BMC Cancer 2006 6:118   doi:10.1186/1471-2407-6-118

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