WHEN IS BONE-SCINTIGRAPHY NECESSARY IN THE ASSESSMENT OF NEWLY-DIAGNOSED, UNTREATED PROSTATE-CANCER

Objective To evaluate the utility of bone scintigraphy in the assessme nt of newly diagnosed, untreated prostate cancer. Patients and methods The probability of a positive bone scan for metastases was analysed f or different threshold values of pre-treatment concentrations of prost ate specific antigen (PSA), clinical stage, tumour grade based on biop sy, and age in 128 men (mean age 69 years, range 50-90) with newly dia gnosed, untreated prostate cancer. The overall survival probabilities estimated from PSA level, extent of bone metastases, tumour grade, cli nical stage, and age were calculated using the product-limit method, R esults The positive predictive values of PSA level for bone metastases at thresholds of 10 and 20 ng/mL were poor (27.5 and 47.5%, respectiv ely) whereas similar threshold levels of PSA gave negative predictive values of 100 and 94%, respectively, for a positive bone scan, In a un ivariate analysis, the overall survival was significantly affected by the extent of bone scan pathology (P < 0.001), the pre-treatment level of PSA (P < 0.001) and tumour grade (P = 0.01), whereas a multivariat e analysis identified, in order of significance, tumour grade (P = 0.0 03), bone scan findings (P = 0.007) and PSA levels (P = 0.03) as indep endent prognostic factors. Conclusions Bone scintigraphy seems to be u nnecessary in the evaluation of newly diagnosed, untreated prostate ca ncer in patients with no clinical signs of bone pathology and serum PS A levels of less than or equal to 10 ng/mL. However, the bone scan acc urately assesses bone metastases and the prognostic significance of bo ne scan findings is superior to that of serum PSA level.