Table 1. Comparative planning studies in prostate cancer.
| Paper [ref] VMAT commercial system | Number of patients | Site and dose | Comparison | PTV | OAR | MU per fraction | Treatment time per fraction |
| Palma et al [51] Predecessor to RapidArc | 10 | Prostate alone 74 Gy in 37 fractions | 3D-CRT vs IMRT(5F,SW) vs CDR-VMAT (SA) vs VDR-VMAT (SA) | IMRT and VMAT – similar PTV coverage and homogeneity (homogeneity inferior to 3D-CRT). Conformity best with IMRT and VDR-VMAT | VDR-VMAT best (compared with IMRT for sparing of rectum and femoral heads; compared with CDR-VMAT for sparing of bladder and rectum) | CDR-VMAT, 491.6; VDR-VMAT, 454.2; IMRT, 788.8; 3D-CRT, 295.5 | |
| Zhang et al [52] | 11 | Prostate + proximal SV 86.4 Gy | IMRT (5F,SS) vs VMAT (SA) | IMRT – slightly higher dose to PTV (V95%, D95%, mean dose and TCP) and better homogeneity compared with VMAT | VMAT better then IMRT (sparing of rectum, bladder, femoral heads) | VMAT, 290; IMRT, 642 | VMAT, 1 min; IMRT, 5 min |
| Kjaer-Kristoffersen et al [53] RapidArc | 8 | Prostate + SV, 78 Gy (5 pts); 74 Gy (1 pt) Prostate bed, 66 Gy (2 pts) | IMRT (5F,SW) vs VMAT (partial SA) | IMRT – slightly better PTV coverage (V95%) but VMAT better in PTV minus rectum coverage. Hotspots higher in VMAT plans. | VMAT better than IMRT (sparing of bladder, rectum). Integral dose to body similar. Low dose bath (V5 Gy) to body larger for VMAT | VMAT, 529; IMRT, 647 | |
| Hardcastle et al [54] SmartArc | 10 | Prostate 78 Gy in 39 fractions | IMRT (7F,SS) vs VMAT (SA) | IMRT and VMAT − similar PTV coverage (except D95% where VMAT had lower values). | VMAT better than IMRT at rectal sparing at doses <50 Gy. VMAT – higher doses to femoral heads. No significant difference in bladder doses. | VMAT, 417; IMRT, 526 | VMAT, 1.3 min; IMRT, 4.5 min |
| Ost et al [55] | 12 | Prostate + SV (76 Gy) and IPL boost (82 Gy). Additional IPL dose level >85 Gy | IMRT (3F,5F,7F,SS) vs VMAT (SA) | IMRT (5F,7F) and VMAT – similar PTV coverage and all better than IMRT 3F. Dose escalation up to 95 Gy to IPL with VMAT | VMAT better at rectal sparing (significant at rectal volumes receiving 20−50 Gy). No difference in integral dose to body. | For 6 MV: VMAT, 447; IMRT (3F), 362; IMRT (5F), 407; IMRT (7F), 434 | VMAT, 1.95 min; IMRT (5F), 3.85 min; IMRT (7F), 4.82 min |
| Weber et al [56] RapidArc | 7 | Recurrent prostate carcinoma 56 Gy in 14 fractions | IMRT (5F,SW) vs IMPT vs VMAT (SA) | IMPT best for PTV coverage, VMAT better than IMRT for GTV and PTV coverage. VMAT (high definition MLC) – best for homogeneity. IMRT, VMAT better than IMPT for conformity | IMPT and RA better than IMRT (sparing of rectum, urethra, bladder). Integral doses to body lowest with IMPT. IMPT best at sparing penile bulb | ||
| Kopp et al [57] RapidArc | 292 | Prostate 77.4 Gy in 43 fraction | IMRT (7F,SW) vs VMAT (SA) | VMAT and IMRT similar PTV coverage (VMAT less homogeneous). VMAT – slightly higher D2% | VMAT better than IMRT (sparing of rectum at high doses, bladder, femoral heads, penile bulb) | ||
| Yoo et al [58] RapidArc | 10 | Prostate, SV and LN (primary) 46.8 Gy; prostate and SV (boost) 28.8 Gy (1.8 Gy per fraction) | IMRT (9F,7F) vs VMAT (SA) vs VMAT (DA) | Primary plans – IMRT better than VMAT (PTV coverage, conformity). Boost plans – similar PTV coverage, homogeneity; IMRT had worse conformity compared to VMAT | Primary plans-IMRT better than VMAT (sparing of bladder, rectum, small bowel). Boost plans – IMRT and DA VMAT better than SA VMAT. Higher integral doses to body with VMAT | Primary plans: VMAT (SA), 429; (DA), 444; IMRT, 1300. Boost plans: VMAT (SA), 443; VMAT (DA), 484; IMRT, 777 | Primary plans: VMAT (SA), 1.5 min; VMAT (DA), 3.1 min; IMRT, 8.1 min. Boost plans: VMAT (SA), 1.5 min; VMAT (DA), 3.1 min; IMRT, 4.9 min. |
| Wolff et al [59] ERGO++ | 9 | Prostate + SV 76 Gy | 3D-CRT vs IMRT (7F,SS) vs VMAT (SA,DA) vs ST | VMAT and ST− better PTV coverage compared with IMRT. Conformity better with IMRT. No difference in homogeneity | ST and IMRT better than VMAT for rectal sparing | VMAT (SA), 386; VMAT (DA), 371; IMRT, 544; ST, 2714 | VMAT (SA), 1.8 min; VMAT (DA), 3.7 min; IMRT, 6 min; ST, 12 min. |
| Tsai et al [60] ERGO++ | 12 | Prostate ± SV 78 Gy in 39 fraction | IMRT (5F,SS) vs VMAT (SA) vs HT | Similar PTV coverage between all three techniques. HT – better conformity | HT better than VMAT and IMRT at rectal sparing at 65 Gy and 40 Gy (VMAT slightly better than IMRT). No difference in bladder and femoral head sparing. | VMAT, 309.7; IMRT, 336.1; HT, 3368 | VMAT, 2.6 min; IMRT, 3.8 min; HT, 3.8 min |
| Rao et al [61] SmartArc | 6 (of 18) | Not specified | IMRT (7F,SS) vs VMAT (SA) vs HT | Similar PTV coverage between all three techniques. VMAT – slightly better homogeneity. | No significant difference between all three techniques VMAT – slightly lower maximum dose to femoral heads compared with HT and IMRT. | VMAT, 549; IMRT, 639 | VMAT, 2.2 min; IMRT, 8.1 min; HT, 4.0 min |
| Shaffer et al [62] Predecessor to RapidArc | 10 | Prostate 74 Gy in 37 fractions + SIB to prostate CTV up to 88.8 Gy | IMRT (9F,SW) vs VMAT (SA) | Volume of CTV boosted and mean dose within boost region higher with VMAT | VMAT, 949; IMRT, 1819 | VMAT, 3.7 min; IMRT, 9.6 min | |
| Crijns et al [64] RapidArc | 11 | Prostate + SV (SIB) 74 Gy + 55 Gy in 37 fractions | IMRT vs VMAT (SA) | No significant difference in PTV coverage (small differences depending on VMAT optimisation approach). IMRT – better homogeneity | No significant differences (except rectal maximum doses lower in some VMAT optimisation approaches). Mean rectal NTCP lower in VMAT | VMAT, 1.2−1.5 min | |
| Guckenberger et al [94] SmartArc | 5 (of 20) | Prostate + SV (SIB) 74 Gy + 60 Gy in 33 fractions | IMRT (7F,SS) vs VMAT (SA) vs VMAT (DA) | Similar PTV coverage (slightly better with DA VMAT). VMAT – better conformity | VMAT slightly better than IMRT at rectal, bladder sparing (except rectal V70 Gy which is higher with VMAT) | VMAT (SA), 465; VMAT (DA), 572; IMRT, 513 | VMAT (SA), 2.08 min; VMAT (DA), 3.87 min; IMRT, 5.82 min |
VMAT, volumetric modulated arc therapy; PTV, planning target volume; OAR, organs at risk; MU, monitor units; Gy, Gray; 3D-CRT, three-dimensional conformal radiotherapy; IMRT, intensity modulated radiotherapy; CDR, constant dose rate; VDR, variable dose rate; 5F, five field; 7F, seven field; 9F, nine field; SW, sliding window; SS, step-and-shoot; SA, single arc; DA, double arc; SV, seminal vesicles; V95%, volume receiving ≥95% prescribed dose; D95%, dose to 95% of volume; TCP, tumour control probability; V5 Gy, volume receiving ≥5 Gy; IPL, intraprostatic lesion; MV, megavoltage; IMPT, intensity modulated proton therapy; MLC, multileaf collimator; D2%, dose to 2% of volume; ST, serial tomotherapy; HT, helical tomotherapy; SIB, simultaneous integrated boost; CTV, clinical target volume; V70 Gy, volume receiving ≥70 Gy.