Prognostic Index of Shamash et al for Predicting the Response of a Patient with Castrate-Resistant Prostate Cancer to Dexamethasone and Diethylstilbesterol Therapy

DS therapy consists of:

(1) 2 mg dexamethasone po once daily

(2) 1 mg diethylstilbesterol po once daily

DS therapy was given for one of the following reasons in a patient who had failed initial hormone therapy for hormone sensitive disease:

(1) rising serum PSA > 20 ng/mL

(2) rising serum PSA AND symptomatic progression before chemotherapy

Parameters:

(1) initial serum PSA in ng/mL

(2) response ratio (serum PSA in percent after 1 month of therapy, compared to the pretreatment PSA)

ratio of PSA after to before therapy =

= (serum PSA 1 month after starting therapy) / (serum PSA before starting therapy)

where:

• A serum PSA of 82.5 ng/mL was the median value.

total score =

= (points for serum PSA) + (points for response ratio)

Interpretation:

• minimum score: 0

• maximum score: 2

• The higher the score the worse the prognosis.