A bone scan index (BSI) can quantify the extent of bone involvement and response to treatment, but it has not been widely accepted, because of its time-consuming nature.
The study is the first to demonstrate that automated BSI calculated with a computer-assisted diagnosis system is effective in judging the chemotherapeutic response of bone metastatic lesions in patients with castration-resistant prostate cancer.
OBJECTIVE:To evaluate the value of an automated bone scan index (aBSI), calculated using a computer-assisted diagnosis system, to indicate chemotherapy response and to predict prognosis in patients with castration-resistant prostate cancer (CRPC) with bone metastasis.
PATIENTS AND METHODS:Forty-two consecutive CRPC patients underwent taxane-based chemotherapy between November 2004 and March 2011 at our institution. The aBSIs were retrospectively calculated at the diagnosis of CRPC and 16 weeks after starting chemotherapy. Cox proportional hazards regression models were applied to multivariate analyses with and without aBSI response in addition to the basic model. Based on the difference in the concordance index (c-index) between each model, the prognostic relevance of adding the aBSI response was determined.
RESULTS:A decrease in aBSI was found in 28 patients (66.7%), whereas a response was shown by bone scan in only 23.8% of patients. Patients with a reduction in aBSI had longer overall survival (OS) in comparison with the other patients (P= 0.0157). Multivariate analysis without aBSI response showed that performance status (P= 0.0182) and PSA response (P= 0.0375) were significant prognosticators. By adding the aBSI response to this basic model, the prognostic relevance of the model was improved with an increase in the c-index from 0.621 to 0.660.
CONCLUSIONS: The aBSI reflected the chemotherapy response in bone metastasis. The index detected small changes of bone metastasis response as quantified values and was a strong prognostic indicator for patients with CRPC.
Written by:
Mitsui Y, Shiina H, Yamamoto Y, Haramoto M, Arichi N, Yasumoto H, Kitagaki H, Igawa M. Are you the author?
Departments of Urology and Radiology, Shimane University School of Medicine, Izumo, Japan.
Reference: BJU Int. 2012 Jul 12. Epub ahead of print.
doi: 10.1111/j.1464-410X.2012.11355.x
PubMed Abstract
PMID: 22788759
UroToday.com Prostate Cancer Section
