Results with External Beam Radiation for Prostate Cancer

**Results with External Beam Radiation**

As noted elsewhere the results for prostate cancer may be better when external beam therapy is given using 3D Conformal therapy or IMRT so higher doses can now be safely given (at least 75Gy) (see Katin nomogram for results) or when a seed implant is combined with external. There is also evidence that for more advanced stages, combining radiation with hormones will improve results.

Survival after Radiation for Prostate Cancer (old data)
Stage	5y	10y	15y
A or T1	57-63%	40 - 60%	35%
B or T2	45 - 47%	25 - 55%	33%
C or T3	33 - 35%	23 - 35%	18%


Prior to the use of PSA it was assumed that most patients treated with standard conventional radiation were cured.Now it is apparent that many of these patients were not cured because their PSA never fell below 1.0 or after a few years the PSA started rising. At the present time there is no consensus on what to do for a patient whose PSA starts rising years after radiation, since most of these men do well without any further treatment. nevertheless they are not considered 'officially cured' if their PSA dose not fall below 1 and stay there.

Results at 5 Years for Prostate Cancer and Radiation

Stage	Alive	Clinically Cured	PSA Cured
T1	85%	81%	62%
T2	82%	74%	53%
T3	66%	55%	34%

J Clin Onc 1995;13:464

as noted elsewhere the control rate depends heavily on the PSA the Gleason score prior to radiation as noted:

Radiation Results based on Gleason Score and PSA

Gleason	Cure	PSA	Cure
2 - 4	63%	< 4	90%
5 - 6	45%	4 - 10	54%
7	20%	10 - 15	31%
8 - 10	24%	15 - 20	24%
		> 20	14%

Series of 480 and dose 66.6Gy IJROBP 1996;36:565

**PSA Cures based on PSA level (prior to treatment) and Gleason Score (GS)**
PSA	GS 2-4	GS 5-6	GS 7	GS 8-10	All
0 - 3.9	89%	86%	86%	75%	86%
4.0 - 9.9	75%	68%	50%	37%	62%
10 - 19.9	59%	54%	29%	18%	44%
20 +	38%	17%	16%	16%	18%
All	71%	55%	37%	25%	50%

Series of 871 men treated with conventional external beam (66.6Gy) from Kestin Cancer 1999;86:1557


So the results using PSA scores show the cure rate with radiation is not as good as originally thought, though probably the same as surgery if you compare patients with the same level of PSA prior to treatment as noted:

PSA Cured Based on Therapy and PSA Level Prior to Treatment

PSA	Radical Prostatectomy	Radiation
0 - 4	92 - 95%	91%
4 - 10	83 - 93%	69 - 85%

IJROBP 1996;35:245


Patients with prostate cancer who elect to have radiation therapy should be treated with conformal 3D therapy and if the cancer is advanced (Gleason score over 6 or PSA over 10) they should consider combining the external beam radiation with either seed implantation, hormonal therapy or both.