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Radiation beams (in yellow) targeted on prostate

Conformal or 3 D Radiation

is a technique where CAT scan images are fed into the treatment planning computer so that the X-rays beams are shaped to 'conform' to the anatomy of the prostate and thus limit the exposure of the normal structures (bladder and rectum) that get hit by radiation. See the nomogram from Katan to predict cure rates.

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We treat all prostate patients with conformal therapy or IMRT.  By using this technique, studies show a better chance of curing the cancer with a  lower risk side effects as noted in the data below:

Prostate Control, Conformal vs Conventional
Cancer Center Conventional Conformal
MD Anderson 53% 72%
Fox Chase 40% 66%

Pollack IJROBP 1996;34:555 and Hanks Cancer 1995;75:1972

Perez recently (IJROBP 2000;47:629) compared their results with conventional radiation with 3D conformal using basically the same dose in both groups (~ 70Gy) and found lower long term rectal problems (1.7% risk versus 8%) and better control rates

5 Year Control Rates by Technique
Group Standard 3D Conformal
Stage T1c 53% 91%
Stage T2 58% 96%
Gleason 5 - 7 53% 96%
PS < 10 65% 96%
PS 10.1 - 20 40% 88%
PS > 20 26% 71%

Perez; IJROBP 2000;47:629

The improved control is due to the ability to safely use higher doses, which improves the cure rate in those with more advanced disease (e.g. those with PSA 20 or higher) as noted:

Control Rate by Dose and Level of PSA (prior to treatment)
Dose PSA 10 - 20 PSA 20+
7000cGy 69% 36%
7500cGy 80% 46%
8000cGy 89% 57%

Hanks IJROBP 1997;37:543

As noted in the complication section the risk of complications is lower with conformal therapy. Short term side effects are lower (34% versus 57% from Cancer 1995;75:1972) and overall results superior as noted:

Treatment Comparisons for T1 and T2 Prostate
technique cure rate potency complications
conventional 80 - 96% 33 - 70% 3 - 17%
conformal 96% 70% 3 - 4%

J Clin Onc 1996;14:304

Another recent study with 3-D radiation again showed lower complications despite higher doses than can be used with conventional irradiation techniques:

Serious (grade 3) Side Effects from Radiation
Technique Dose grade 3 complications
conventional < 7000cGy 3.5%
conventional > 7000cGy 6.9%
3-D 7500cGy 1.6%