Radium-223-Dichloride in Castration Resistant Metastatic Prostate Cancer-Preliminary Results of the Response Evaluation Using F-18-Fluoride PET/CT: Beyond the Abstract

This article [1] is a comprehensive analysis of 10 prostate cancer patients who received Ra-223-treatments. These patients were imaged with multiple quantitative PET methods according to our own algorithm [2], including fluoro-18-choline-PET and sodium fluoride-18 PET. These patients were additionally treated with multidisciplinary methods, including other radiation therapies. We recently reported an overall survival of 8.4 years in 46 patients of high-risk T3-4NXM1 primarily metastatic prostate cancer [2].

It turned out, that the response to Ra-223-treatment could be best assessed with sodium fluoride-18 PET. The local reactions in the metastatic bone were seen in the PET studies.

However, it was not possible to predict the outcome of the therapy after the first Ra-223-therapy cycle, but after the 6th cycle. All 10 patients demonstrated at least minor skeletal response in sodium fluoride-18 PET. Also flare phenomenon was sometimes associated with early interim imaging after the first cycle.

Now, these findings have been characterized by other investigators, by introducing quantitative PET interpretation criteria [3].  Our modified PERCIST criteria for response assessment in Ra-223-treatment are useful and simple, and can be used in the clinical routine. According to our experience Ra-223 is an essential part of treatment of metastatic castration resistant prostate cancer, if the disease is mainly in the skeleton.

Written by: Kalevi Kairemo, Docrates Cancer Center, Helsinki, Finland & MD Anderson Cancer Center, Houston, TX, USA

References:
  1. Kairemo K, Joensuu T. Radium-223-Dichloride in Castration Resistant Metastatic Prostate Cancer-Preliminary Results of the Response Evaluation Using F-18-Fluoride PET/CT. Diagnostics (Basel). 2015; 5: 413-427.
  2. Joensuu T, Joensuu G, Kairemo K, Kiljunen T, Riener M, Aaltonen A, et al. Multimodal Primary Treatment of Metastatic Prostate Cancer with Androgen Deprivation and Radiation. Anticancer Res. 2016; 36: 6439-6447.
  3. Rohren E, Etchebehere EC, Araujo JC, Hobbs BP, Swanston NM, Everding M, et al. Determination of Skeletal Tumor Burden of 18F-Fluoride PET/CT. J Nucl Med Mol 2015; 56: 1506-1512. 

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