Introduction
Biology
-
The assumption of an α/β value for prostate cancer of as low as 1.5 Gy might lead to an overestimation of the effects of hypofractionation.
-
Fractionation sensitivity of prostate cancer and surrounding tissues does not decisively differ; therefore, hypofractionated and accelerated study designs with a reduced total dose seem promising and may be possible without any deterioration of the therapeutic ratio.
-
The time factor may contribute in part to the efficacy of hypofractionation.
-
Due to the described uncertainties in assuming fractionation sensitivities and the steep dose-response effects for tumor control and for normal tissue toxicity, fractionation concepts have to be tested in well-designed randomized trials, such as the CHHiP, HYPRO and the RTOG 0415 studies and should not be mathematically derived.
-
Only evidence-based fractionation schedules should be used outside of clinical trials.
-
Treatment interruptions leading to prolonged overall treatment times can have negative consequences and have to be adequately compensated.
Technology
Moderate hypofractionation
Study |
n
| Median FU (months) | Risk groups/Gleason scores | Techniques | Regimen (TD/fx/SD) | Outcome | Toxicity e = early, otherwise: late tox |
---|---|---|---|---|---|---|---|
RTOG 0415
Lee et al. [11] | 542 550 | 70 | Low risk | 3D-CRT/IMRT daily IGRT | 73.8 Gy/41 fx/1.8 Gy
70 Gy/28 fx/
2.5 Gy
no ADT | 5 years DFS 85.3 % (NS) 5 years DFS 86.3 % | G 2 GI 11.4 % (p = 0.05) G 2 GU 20.5 % (p = 0.09) G 2 GI 18.3 % G 2 GU 26.2 % |
Lukka et al. [12] | 466 470 | 68 | 60 % GS ≤6 31 % GS 7 9 % GS 8–10 | 3DCRT No IGRT | 52.5 Gy/20 fx/2.63 Gy
66 Gy/33 fx/
2.0 Gy
no ADT | 5 years FFBF 47 % (NS) 5 years FFBF 42 % | G 3–4 GU + GI 3.2 % (NS) G 3–4 GU + GI 3.2 % |
HYPRO
Incrocci et al. [15] | 397 407 | 60 | 27 % intermediate 73 % high | 95 % IMRT/IGRT | 78 Gy/39 fx/
2.0 Gy
64.6 Gy/19 fx/3.4 Gy
66 % ADT | 5 years RFS 77.1 % (NS) 5 years RFS 80.5 % | 3 years G2+ GU 39 % 3 years G3+ GU12.9 % 3 years G2+ GI 17.7 % (3 years G3+ GU p = 0.02) 3 years G2+ GU 41.3 % 3 years G3+ GU 19.0 % 3 years G2+ GI 21.9 % |
CHHiP
| 1065/37 fx 1074/20 fx 1077/19 fx | 62 | 15 % low 73 % intermediate 12 % high | IMRT IGRT not mandatory | 74 Gy/37 fx/
2.0 Gy
60 Gy/20 fx/
3.0 Gy
57 Gy/19 fx/
3.0 Gy
97 % ADT | 5 years PFS (NS) 88.3 % (37 fx) vs. 90.6 % (20 fx) vs. 85.9 % (19 fx) |
Acute G2 + GI (p < 0.0001)
25 % (37 fx) 38 % (20 fx) 38 % (19 fx)
5 years G 2+ GI (RTOG, NS)
13.7 % (37 fx) 11.9 % (20 fx) 11.3 % (19 fx)
5 years G 2 + GU (RTOG, NS)
9.1 % (37 fx) 11.7 % (20 fx) 6.6 % (19 fx) |
Fox Chase
Shaikh et al. [19]abs | 151 152 | 68 | 34 % GS ≤6 47 % GS 7 19 % GS 8–10 | IMRT daily IGRT | 70.2 Gy/26 fx/
2.7 Gy
76 Gy/38 fx/
2.0 Gy
46 % ADT | 5 years BCDF 23 % (NS) 5 years BCDF 21 % | 5 years G 2+ GU 13 % (NS) 5 years G2+ GI 9 % (NS) 5 years G2+ GU 22 % 5 years G2+ GI 9 % incontinence worse at 3 years (p = 0.03) but not at 5y |
Yeoh et al. [20] | 108 109 | 90 | n. s. | 2D/3DCRT No IGRT | 55 Gy/20 fx/
2.75 Gy
64 Gy/32 fx/
2.0 Gy
no ADT | 7.5 years FFBF 53 % (p < 0.05) 7.5 years FFBF 34 % | 4 years GU; HR: 1.58 (95 % CI, 1.01–2.47) favoring hypofractionation, but no difference GI + GU at 5 years FU |
102 101 | 60 | 28 % low 71 % intermediate 1 % high | IMRT IGRT | 72 Gy/30 fx/
2.4 Gy
75.6 Gy/42 fx/
1.8 Gy
21 % ADT | 5 years FFBF 96 % (NS) 5 years FFBF 92 % | 5 years G2+ GU 16 % (NS) 5 years G2+ GI 10 % (NS) 5 years G2+ GU 17 % 5 years G2+ GI 5 % | |
Arcangeli et al. | 83 85 | 70 | 26 % GS <7 74 % GS >7 | 3DCRT No IGRT | 62 Gy/20 fx/
3.1 Gy
80 Gy/40 fx/
2.0 Gy
100 % ADT | 5 years FFBF 85 % (p = 0.065) 5 years FFBF 74 % | 3 years G 2+ GU 16 % (NS) 3 years G 2+ GI 17 % (NS) 3 years G 2+ GU 11 % 3 years G 2+ GI 14 % |
Toxicity
Hypofractionation in adjuvant and salvage treatment
Current trials in moderate hypofractionation
Summary on moderate hypofractionation
Extreme hypofractionation
Clinical evidence
n
| Median FU (months) | Risk group | Techniques | Regimen (TD/fx) | Outcome | Toxicity | |
---|---|---|---|---|---|---|---|
Aluwini [39] | 162 | 28 | Low/intermediate | n. s. | 38 Gy/4 fx | BC 98 % @ 3 years | G 2 GU 15 % G 2 GI 3 % |
Bolzicco [40] | 100 | 36 | 41 % low 42 % intermediate 17 % high | Robotic IGRT | 35 Gy/5 fx 29 % ADT | BC 96 % | G 1/2/3 GU 4 %/3 %/1 % G 1/2/3 GI 2 %/1 % |
Chen et al. [41] | 100 | 28 | 37 % low 55 % intermediate 8 % high | Robotic IGRT | 35–36.25 Gy/5 fx 11 % ADT | BRFS 99 % @ 2 years | 2 y G ≥ 2 GU 31 % 2 y G ≥ 2 GI 1 % |
D’Alimonte et al. [42] | 84 | 50 | 100 % low | IMRT/IGRT | 35 Gy/5 fx | BC 98 % | G 2/≥3 GU 5/1 % G 2/≥3 GI 5/1 % |
Friedland et al.[34] | 122 | 24 | 72 % low 28 % intermediate + high | Robotic IGRT | 35 Gy/5 fx - 36.3 Gy/5 fx 19 % ADT | FFBF 97 % | G 3+ GU 0 % G 3+ GI 1 % |
Freeman (2015) (RPCR registry) | 1743 |
n. s. | 41 % low 42 % intermediate 10 % high 7 % data missing | Mainly robotic IGRT | 35–40 Gy/ 4–5 fx (8 % SBRT-boost 19.5–21.8 Gy/3 fx after 45–50 Gy EBRT) | FFBF 92 % @ 2 years 99 % low risk 97–85 % interm. 87 % high | G3 GU 0 % G3 GI 0 % |
Fuller et al. [44] | 260 | 20 | 45 % low 55 % intermediate | n. s. | 38 Gy/4 fx | BRFS 98 % @ 3 years | G 3 GU 2 % (any G 44 %) G 3 GI 0 % (any G 11 %) |
Katz and Kang [35] | 515 | 72 | 63 % low 30 % intermediate 7 % high | Robotic IGRT | 35–36.25 Gy/5 fx | FFBF @ 7 years 96 % (low risk) 89 % (interm.r.) 69 % (high risk) | G ≥ 2 GU 9 % G ≥ 2 GI 4 % |
King et al. [33] | 67 | 32 | 100 % low | Robotic IGRT | 36.25 Gy/5 fx | 92 % | G ≥ 2 GU 7 % G ≥ 2 GI 12 % |
Loblaw et al. [37] | 84 | 55 | 100 % low | IMRT/IGRT | 35 Gy/5 fx | 70 % | 5 y G ≥ 2 GU 5 % 5 y G ≥ 2 GI 7 % |
Lukka et al. [45] | 240 | n. s. | Low | IMRT/IGRT | 36.3 Gy/5 fx 51.6 Gy/12 fx | n. s. | Changes in EPIC bowel & urinary domain scores: both regimens well tolerated |
Mantz et al. [46] | 91 | 24 | Low and intermediate | IMRT/IGRT | 36.3 Gy/5 fx 22.0 Gy/4 fx | FFBF 97 % | G 3+ GU 5 % G 3+ GI 1 % (G 4) |
129 | 30 | 100 % intermediate | Robotic IGRT | 40 Gy/5 fx No ADT | BRFS 94 % @ 4 years | G 2 GU 10 % G 2 GI 2 % | |
Menkarios et al. [49] | 80 | 33 | 100 % low | IMRT/IGRT | 45 Gy/5 fx | BC 98 % @ 5 years | G ≥ 2 GU 14 % G ≥ 2 GI 16 % |
Oliai et al. [50] | 70 | 37 | 51 % low 31 % intermediate 17 % high | Robotic IGRT | 35 Gy/5 fx 36.3 Gy/5 fx 37.5 Gy/5 fx 33 % ADT | FFBF 100 %/95 %/77 % | G 3+ GU 3 % G 3+ GI 0 % |
Quon et al. [51] | 84 | 18 | 100 % low | IMRT/IGRT | 35 Gy/5 fx | BRFS 99 % @ 3y | G 2 GU 2 % G 2 GI 5 % |