Table 3.
Comparison of outcomes using the Kaplan–Meier estimator with log-rank tests for stratified outcomes
| LC | FFFM | RFS | OS | |||||
|---|---|---|---|---|---|---|---|---|
| Factorsa | 3-Year LC | P | Median time | P | Median time | P | Median time | P |
| Institute | ||||||||
| Academic | 68.3 | 17.9 | 12.7 | 42.0 | ||||
| Non-academic | 62.6 | 0.22 | 21.3 | 0.61 | 12.0 | 0.81 | 55.6 | 0.21 |
| Age, years | ||||||||
| <73 | 61.7 | 19.0 | 11.3 | 51.4 | ||||
| ≥73 | 66.4 | 0.27 | 19.7 | 0.24 | 14.3 | 0.13 | 55.6 | 0.80 |
| Sex | ||||||||
| Male | 64.8 | 21.3 | 12.0 | 55.6 | ||||
| Female | 65.1 | 0.41 | 17.9 | 0.44 | 12.4 | 0.65 | 48.8 | 0.50 |
| ECOG Performance Status | ||||||||
| 0 | 66.5 | 18.0 | 12.9 | 60.3 | ||||
| 1 | 60.9 | 23.0 | 12.0 | 40.1 | ||||
| 2–3 | 65.6 | 0.46 | 21.6 | 0.89 | 10.0 | 0.50 | 33.1 | 0.01 |
| Primary origin | ||||||||
| Colon | 64.0 | 23.5 | 14.2 | 55.2 | ||||
| Rectum | 66.5 | 0.75 | 17.8 | 0.12 | 11.7 | 0.06 | 51.7 | 0.75 |
| DFI | ||||||||
| <17.2 months | 62.3 | 18.2 | 11.7 | 38.0 | ||||
| ≥17.2 months | 67.2 | 0.34 | 25.4 | 0.04 | 14.7 | 0.09 | 60.3 | 0.26 |
| Oligometastatic state | ||||||||
| Oligo-recurrence | 64.4 | 23.2 | 12.9 | 55.6 | ||||
| Sync-oligometastases | 70.9 | 9.4 | 9.4 | 35.9 | ||||
| Unclassified oligometastases | 59.5 | 0.47 | 17.9 | 0.08 | 12.6 | 0.29 | 37.6 | 0.40 |
| History of local therapy for metastases | ||||||||
| Yes | 73.3 | 14.3 | 10.6 | 42.0 | ||||
| No | 63.9 | 0.06 | 27.2 | <0.01 | 17.5 | <0.01 | 65.6 | 0.16 |
| Chemotherapy | ||||||||
| Before SBRT - yes | 69.8 | 12.7 | 11.3 | 55.6 | ||||
| Before SBRT - no | 59.5 | 0.09 | 25.0 | <0.01 | 14.7 | <0.01 | 48.8 | 0.36 |
| Concurrent SBRT - yes | N/A | 6.6 | 6.9 | 34.2 | ||||
| Concurrent SBRT - no | 65.8 | 0.01 | 21.3 | 0.02 | 12.6 | 0.01 | 54.3 | 0.16 |
| After SBRT - yes | 68.8 | 13.1 | 11.7 | 50.3 | ||||
| After SBRT - no | 68.5 | 0.92 | 23.2 | 0.08 | 12.7 | 0.41 | 51.5 | 0.66 |
| Number of metastases | ||||||||
| 1 | 60.7 | 25.0 | 12.9 | 55.8 | ||||
| 2–5 | 73.6 | 0.09 | 13.1 | <0.01 | 11.3 | 0.15 | 35.8 | 0.07 |
| SBRT date | ||||||||
| 2004–09 | 58.8 | 20.4 | 12.6 | 48.6 | ||||
| 2010–15 | 69.3 | 0.03 | 19.0 | 0.83 | 12.4 | 0.64 | 60.8 | 0.11 |
| Maximum tumor diameter | ||||||||
| <1.5 cm | 69.4 | 23.5 | 16.0 | 55.6 | ||||
| ≥1.5 cm | 56.1 | 0.07 | 16.3 | 0.03 | 11.3 | 0.02 | 48.6 | 0.01 |
| Located lobe | ||||||||
| Upper or middle lobe involvement | 70.3 | 25.0 | 16.5 | 60.8 | ||||
| Lower lobe | 67.9 | 0.75 | 14.2 | <0.01 | 11.1 | 0.02 | 36.6 | 0.02 |
| Field coplanarity | ||||||||
| Coplanar field | 60.3 | 23.0 | 13.3 | 54.3 | ||||
| Non-coplanar field | 66.7 | 0.41 | 18.5 | 0.67 | 12.4 | 0.99 | 51.5 | 0.50 |
| Beam | ||||||||
| Static | 54.5 | 21.3 | 12.7 | 55.6 | ||||
| Arc | 69.2 | 0.02 | 16.9 | 0.36 | 10.1 | 0.29 | 42.0 | 0.76 |
| Dose prescription | ||||||||
| Isocenter | 57.4 | 18.8 | 12.0 | 48.8 | ||||
| D95 of PTV | 86.3 | 25.0 | 16.3 | 68.9 | ||||
| Others | 77.7 | <0.01 | 31.3 | 0.96 | 9.2 | 0.28 | N/A | 0.62 |
| Calculation algorithm | ||||||||
| Type A | 54.5 | 18.8 | 11.6 | 51.4 | ||||
| Type B | 72.7 | <0.01 | 20.4 | 0.41 | 13.1 | 0.17 | 51.7 | 0.60 |
| Energy | ||||||||
| 6 MV only | 65.1 | 19.0 | 12.6 | 51.4 | ||||
| Others | 65.1 | 0.62 | 23.5 | 0.54 | 12.0 | 0.89 | 55.6 | 0.70 |
| BED10 dose of IC | ||||||||
| <115 Gy | 56.5 | 17.0 | 11.7 | 41.0 | ||||
| ≥115 Gy | 70.3 | 0.06 | 23.4 | 0.12 | 12.7 | 0.06 | 84.0 | 0.01 |
| OTT of SBRT | ||||||||
| <7 days | 67.1 | 18.5 | 12.7 | 50.3 | ||||
| ≥7 days | 69.2 | 0.54 | 19.7 | 0.45 | 12.4 | 0.47 | 51.5 | 0.74 |
aECOG = Eastern Cooperative Oncology Group, N/A = not applicable, D95 of PTV = dose covering 95% of the planning target volume, IC = isocenter, OTT = overall treatment time.