CHHIP

CHHIP stands for Conventional or Hypofractionated High Dose Intensity Modulated Radiotherapy for Prostate Cancer, a treatment protocol currently undergoing clinical trials for the treatment of prostate cancer using external beam radiotherapy.

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Protocol Details

The main arm of the protocol prescribes 74 Gy to the prostate, with optional additional volumes around the prostate (such as the seminal vesicles and nodes prescribed to 71 Gy and 59 Gy. Each target with a prescribed dose must receive at least 95% of that dose to at least 99% of its volume and the dose to the 'hottest' 1% of the volume must be recorded. There are various limits on doses delivered to healthy tissues:

Rectal dose constraints:

• No more than 68% dose (50 Gy) to 60% of the rectum
• No more than 81% (60 Gy) to 50%
• No more than 88% (65 Gy) to 30%
• No more than 95% (70 Gy) to 15%
• No more than 100% (74 Gy) to 5%

Femoral head constraints:

• No more than 50% of volume to receive more than 68% dose (50 Gy)

Bladder constraints:

• No more than 68% dose (50 Gy) to 50 % of the volume
• No more than 81% (60 Gy) to 25%
• No more than 100% (74 Gy) to 5%

Bowel constraints:

• No more than 68% dose (50 Gy) to 17 cc of the bowel

Additional targets:

• No more than 68% dose (50 Gy) to 50% of the urethral bulb
• No more than 81% (60 Gy) to 10% of the urethral bulb
• No more than 41% dose (30 Gy) to 80% of the rectum
• No more than 54% (40 Gy) to 70% of the rectum

The protocol has three arms, comparing conventional 2-Gray-per-fraction treatments against hypofractionated 3-Gray-per-fraction. One arm of the trial is the control group, receiving the standard 74 Gy in 37 fractions. The second arm prescribes 60 Gy in 20 fractions and the third prescribes 57 Gy in 19 fractions. The dose constraints for the hypofractionated arms of the trial are dose-scaled equivalents of those determined for the 74 Gy arm.

Eligibility

Inclusion Criteria a) Histologically confirmed, previously untreated locally confined adenocarcinoma of the prostate b) All clinical T categories

Exclusion criteria a) Patients with T3 cancers with Gleason Sum=8 cancers are ineligible b) Prior pelvic radiotherapy or radical prostatectomy c) Previous androgen deprivation d) Life expectancy <10 years e) Previous active malignancy within the last five years other than basal cell carcinoma f) Co-morbid conditions likely to impact on the advisability of radical radiotherapy (e.g. previously inflammatory bowel disease, previous colorectal surgery, significant bladder instability or urinary incontinence) g) Full anticoagulation with e.g. Warfarin or Heparin h) Hip prosthesis or fixation which would interfere with standard radiation beam configuration

Trial

The trial is being run and co-ordinated by Prof David Dearnaley at the Institute of cancer Research, Surrey.

The trial aims to recruit over 2162 patients. As of May 2007, 671 patients had been recruited onto the trial, an accrual of 30%. The trial will close in 2015.

References

UKCRN Database