Wednesday, June 21, 2017

Eighth randomized clinical trial of hypofractionated radiation therapy

We now have an eighth randomized clinical trial of hypofractionated radiation therapy. There are no surprises: it showed that oncological and toxicity outcomes were not significantly different between the two regimens. We last looked at it here. This trial is unusual because of the length of follow-up.

Arcangeli et al. report the 10-year outcomes of their study covering 168 high risk patients treated using 3D-CRT (not IMRT) at the Regina Elena Cancer Institute in Rome between 2003 and 2007. The details of the treatments were as follows:
  • Half (85 patients) received conventionally fractionated (Conv)  80 Gy in 40 fractions
  • Half (83 patients) received hypofractionated (Hypo) 62 Gy in 20 fractions
After a median of 9 years of follow-up:
  • 10-year freedom from biochemical failure was 72% for the Hypo group vs. 65% for the Conv group.(no statistically significant difference)
  • 10-year prostate cancer -specific survival was 95% for the Hypo group vs. 88% for the Conv group (no statistically significant difference)
  • 10-year overall survival was 75% for the Hypo group vs. 64% for the Conv group (no statistically significant difference)
  • Hypofractionation was a significant variable in determining prostate cancer-specific survival in multivariate analysis
  • There were no differences in late-term grade 2 or higher urinary or rectal toxicity between the 2 groups.

There are a couple of caveats. For those who insist on rigorous analysis, the Hypo group had worse oncological and toxicity outcomes on an intention-to-treat basis. It was only after the patients were analyzed according to the treatment they actually received that the lack of statistically significant difference became apparent. James Yu, in an accompanying editorial, points out that blood in urine was 16.5% for the Hypo group vs. 3.6% for the Conv group. This may be a caution that hypofractionation should not be attempted using 3D-CRT. In the US, where IMRT is widely available, this should not be an issue.

Here's the table summarizing all 8 randomized clinical trials:


Randomized Clinical Trial
Risk Groups
Fractionation
5-yr bPFS
Urinary toxicity
Grade 2+
Rectal toxicity
Grade 2+
Ref.
PROFIT
100% intermediate
60 Gy/20fx
78 Gy/39fx
85%
85%
22%
21%
8%
14%
1
Fox Chase
67% Intermediate, 33% high
70.2 Gy/26fx
76 Gy/38fx
77%
79%
22%
13%
18%
23%
2
CHHiP
73% intermediate, 15% low, 12% high
60 Gy/20fx
74 Gy/37fx
91%
88%
12%
9%
12%
14%
3
MD Anderson
71% intermediate, 28% low, 1% high
72 Gy/30fx
75.6 Gy/42fx
89%†
85%†
16%
17%
10%
5%
4
RTOG 0415
100% low risk
70 Gy/28fx
73.8 Gy/41fx
94%
92%
30%
23%
22%
14%
5
HYPRO
>70% high, <30% intermediate
64.6 Gy/19fx
78 Gy/39fx
81%
77%
41%
39%
22%
18%
6, 7
Cleveland Clinic
49% low, 51% intermediate
70 Gy/28fx
78 Gy/39fx
94%
88%
1%
2%
5%
12%
8
Regina Elena
100% high risk
62 Gy/20 fx
80 Gy/40 fx
72%*
65%*
21%
14%
NA
NA
9
*10-year figures for the Regina Elena trial
† 8-yr failure-free survival update for MD Anderson

1 comment:

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