Table 2.
Studies on brain metastases SRT reporting the normal brain volume as predictive factor of radionecrosis.
| Authors (Year) | Treatment Machine | Number of Targets (Type) | Median Dose/ Number of Fractions |
Definition of Predictive Factor | Predictive Dosimetric Factor | Radionecrosis Rate Above/Below of the Limit |
Median Follow-Up (Months) |
|---|---|---|---|---|---|---|---|
| SINGLE FRACTION | |||||||
| Peng (2019) | CK | 294 (brain metastases) | 20 Gy/1 fr. (14 to 25 Gy/1 to 5 fr.) | Brain + target | V14 ≥ 20 cc | 12.1%/NR (all grades) 3.4%/NR (grade 3) |
21.7 |
| Minniti (2016) | LINAC | 343 (brain metastases) | 15 to 18 Gy | Brain − GTV | V12 > 13.2 cc | 28%/13% | 29 |
| Sneed (2015) | GK | 2200 (brain metastases) | 19 Gy (7.5 to 20 Gy) |
Brain + target | V12 > 3.3 cc V10 > 4.3 cc |
13–14%/NR | 9.9 |
| Minniti (2011) | LINAC | 310 (brain metastases) | 18 Gy (15 to 20 Gy) |
Brain − GTV | V10 > 12.6 cc V12 > 10.9 cc |
47%/NR | 9.4 |
| Blonigen (2010) | LINAC | 173 (brain metastases) |
18 Gy (12 to 22 Gy) |
Brain + target | V10 > 6.4 cc V12 > 4.8 cc |
>34.6%/7.1% | 13.7 |
| Chin (2001) | GK | 243 patients (variable lesions) | NR | Brain + target | V10 > 10 cc | 76%/41% | NR |
| Korytko (2006) | GK | 198 (variable lesions) | 17.3 Gy (11–25) | Brain + target | V12 > 10 cc | 55.3%/22.5% (symptomatic RN) | NR |
| Voges (1996) | LINAC | 135 (variable lesions) |
15 Gy (7 to 25 Gy) |
Brain + target | V10 > 10 cc | 23.7%/0% | 28.1 |
| THREE FRACTIONS | |||||||
| Dore (2017) | LINAC | 97 (surgical cavities) | 23.1 Gy/3 fr. | Brain − PTV (2 mm margin CTV-PTV) | V21 (median 4.6 cc in cohort without RN vs. 10 cc in cohort with RN) | NR | 17 |
| Minniti (2016) | LINAC | 343 (brain metastases) | 27 Gy/3 fr. | Brain − GTV | V18 > 30.2 cc | 14%/5% | 29 |
| Minniti (2014) | LINAC | 171 (brain metastases) | 27 Gy/3 fr. (27 to 36 Gy/3 fr.) | Brain − GTV | V21 ≥ 20.9 cc V18 ≥ 26.2 cc |
14%/4% | 11.4 |
| Inoue (2013) | CK | 159 (brain metastases) | 27 Gy/3 fr. | Brain − GTV | V23.1 ≥ 5 cc V23.1 ≥ 7 cc |
5.7%/1.4% 9%/0% (RN requiring surgery) |
7 |
| Minniti (2013) | LINAC | 101 (surgical cavities) | 27 Gy/3 fr. | Brain − GTV | V24 ≥ 16.8 cc | 16%/2% | 16 |
| FIVE FRACTIONS | |||||||
| Andruska (2020) |
GK
LINAC |
117 (brain metastases + surgical cavities) | 30 Gy/5 fr. (25 to 35 Gy/5 fr.) | Brain − GTV | V25 > 16 cc V30 > 30 cc |
21%/2% (symptomatic RN) | 10.3 |
| Faruqi (2020) | LINAC | 250 (brain metastases + surgical cavities) | 30 Gy/5 fr. (20 to 35 Gy/5 fr.) | Brain − GTV/CTV | V30 ≥ 10.5 cc | 61.1%/12.6% (symptomatic RN) | 12 |
| Inoue (2014) | CK | 85 (brain metastases) | 31 Gy/5 fr. (25 to 40 Gy/5 fr.) | Brain − GTV | V28.8 > 7 cc V28.8 > 3 cc |
12.5%/0% (RN requiring surgery) 11.2%/0% (symptomatic RN) |
8 |
| Ernst-Stecken (2006) | LINAC | 72 (brain metastases) | 30–35 Gy/5 fr. | Brain − GTV | V20 > 23 cc | 70%/14% | 7 |
Vx: volume of receiving x Gy. NR = not reported, CK = CyberKnife, LINAC = Linear accelerator, GK = GammaKnife, RN = radionecrosis.