Patients with localized prostate cancer may be treated by external-beam radiotherapy. A patient's 60 month (5 year) recurrence free survival following three-dimensional conformal radiation therapy can be predicted based on pretreatment clinical findings and the radiation dose. The study was based on findings in 1, 042 patients treated at the Memorial Sloan-Kettering Cancer Center in New York City.
Parameters used in score:
(1) pretreatment PSA
(2) clinical stage
(3) Gleason score on needle biopsies (sum of 2 main Gleason grades in histologic sections, ranging from 2 to 10)
(4) dose of radiation therapy in Gy
(5) hormone therapy
|
Pretreatment PSA in ng/mL |
Points |
|
0.3 |
0 |
|
1 |
28 |
|
2 |
45 |
|
3 |
54 |
|
4 |
61 |
|
5 |
66 |
|
6 |
70 |
|
7 |
73 |
|
8 |
77 |
|
9.5 |
80 |
|
25 |
92 |
|
50 |
95 |
|
100 |
100 |
points for pretreatment PSA =
= (0.1292945 * ((LN(PSA))^4)) – (1.294772 * ((LN(PSA))^3)) + (1.0560065 * ((LN(PSA))^2)) + (25.699211 * (LN(PSA))) + 27.018347
where:
• LN = natural logarithm
• The approximation equation was generated using JMP.
|
Parameter |
Finding |
Points |
|
clinical stage |
T1c |
0 |
|
|
T2a |
12 |
|
|
T2b |
20 |
|
|
T2c |
24 |
|
|
T3a |
22 |
|
|
T3b |
22 |
|
|
T3c |
26 |
|
Gleason score on needle biopsies |
2 |
0 |
|
|
3 |
0.25 |
|
|
4 |
0.5 |
|
|
5 |
1 |
|
|
6 |
2 |
|
|
7 |
5 |
|
|
8 |
11 |
|
|
9 |
17 |
|
|
10 |
23 |
|
hormone therapy |
yes |
0 |
|
|
no |
4 |
|
radiation dose in Gy |
86.4 |
0 |
|
|
72 |
9 |
|
|
68 |
17.5 |
|
|
64.8 |
24 |
points for radiation dose between 64.8 and 86.4 Gy =
= (0.0658064 * ((dose)^2)) – (11.07689 * (dose)) + 465.77404
total score =
= SUM(points for all 5 parameters)
Interpretation:
• minimum score: 0
• maximum score: around 177
• The higher the score, the greater the chance for recurrence.
• The total score can be used to estimate the probability of 60 month recurrence free survival, plus/minus 10%. It assumes that the person does not die from another cause first.
• If a person is recurrence free at 5 years, then recurrence after that time is very rare.
|
Total Score |
Percent 60 Month Recurrence Free |
|
<= 36 |
99% |
|
45 |
98% |
|
67 |
95% |
|
83 |
90% |
|
98 |
80% |
|
108 |
70% |
|
121 |
50% |
|
133 |
30% |
|
146 |
10% |
|
>= 160 |
1% |
percent recurrence free with score 36 to 98 =
= (-0.000108 * ((points)^3)) + (0.0158251 * ((points)^2)) – (0.8755 * (points)) + 115.06825
percent recurrence free with score 98 to 160 =
= (0.0004759 * ((points)^3)) - (0.179904 * ((points)^2)) + (20.923274 * (points)) – 690.7118
Specialty: Hematology Oncology, Surgery, general, Urology
