The median
tumor volume of the metastatic site treated with SBRT was 27.6±11.6 cc. Minimum
dose (Dmin), maximum dose (Dmax) and mean dose (Dmean) for entire cohort were
14.18±1.02, 20.99±1.95 and 18.95±3.26, respectively. Spinal cord volume was
4.41±1.65. the maximum dose of spinal cord (Dmax), the dose to 0.35 cc of
spinal cord (D0.35), the dose to 10% of the spinal cord (D10%) and the volume
of spinal cord receiving 10 Gy (V10) were 11.68±0.85, 8.91±0.93, 8.53±0.87 and
0.14±0.11, respectively. When compared the CTV dosimetry according to SBRT dose
there was no significant difference for 1x16 Gy or 1x18 Gy. Also, spinal cord
dosimetry was not different for two groups.
Half
of the patients (29 pts, 50%) had breast cancer, 15 patients (25%) had prostate
cancer, 5 patients (8%) had lung cancer and remaining 9 patients (17%) had
various (rectum, cervical, gastric etc.) primaries. A total of 64 lesions were
treated with SBRT in a total of 58 patients. The
SBRT doses were 1x16 Gy in majority of the patients (40 pts, 69%), and eighteen
patients (31%) treated with 1x18 Gy. The median follow-up of entire cohort was
12 months (range, 1- 56 months). For the entire cohort, complete response (CR),
partial response (PR) and progressed disease (PD) rates were 31%, 59% and 10%,
respectively. Local recurrence was seen in ten patients (17%) within median 6
months after SBRT. The 1 and 2 year OS rates were 84% and 65%, respectively,
and the 1 and 2 year PFS rates were 73% and 45%, respectively (Figure 2A and
2B). The 1 and 2 year LC rates were 81% and 70%, respectively (Figure 2C). We
performed univariate
analysis related with OS, PFS and LC. Patients with primary breast
histology have better OS than other patients (24.3 vs. 13.9 months,
p=0.024). OS (18.7 vs. 38.8 months,
p=0.013) and PFS (5.7 vs. 15.9 months, p<0.001) were worse in patients with
recurrence ≤12 months. No patient experienced ≥grade 3 acute or late toxicity.
7 patients (12%) had grade 2, 10 had grade 1 toxicities.