Survival analysis: Kaplan-Meier curves
Parameters:
(1) primary Gleason grade (from 1 to 5)
(2) serum testosterone in ng/mL
(3) serum growth hormone (GH) in µU/mL
(4) metastatic status from TNM (0 if M0, 1 if M1)
(5) age of the patient in years
where:
• According to Documenta Geigy Scientific Tables 7th Edition (page 719) 1 IU growth hormone was 1 mg. Therefore 1 µU/mL would be 1 ng/mL.
prognostic index for M0 patients =
= (0.84 * (Gleason grade)) - (0.51 * (serum testosterone))
prognostic index for M1 patients =
= (0.67 * (Gleason grade)) - (0.003 * (age in years)) - (0.50 * (serum testosterone)) + (0.122 * (serum growth hormone))
prognostic index for all patients =
= (0.67 * (Gleason grade)) - (0.003 * (age in years)) - (0.47 * (serum testosterone)) + (0.068 * (serum growth hormone)) + (0.49 * (M value))
Interpretation:
• The higher the value for the prognostic index, the worse the prognosis.
Limitations:
• The study was performed in 1985 and was based on even earlier data. Patients today are likely to have better survival, although the relative survival between risk groups may still hold.
• Patients are being diagnosed at earlier clinical stages today.
