Radium-223 IN metastatic hormone-sensitive high-grade prostate cancer: initial experience

Our study evaluates the feasibility of compassionate exemption of Radium-223 (²²³Ra) treatment in metastatic hormone-sensitive high-grade prostate cancer (mHSHGPC) patients with concomitant androgen deprivation-therapy (ADT). Seven patients with mHSHGPC, were treated with six cycles of ²²³Ra plus ADT. All patients had undergone to ¹⁸F-NaF-PET/CT. A qualitative analyses of the ¹⁸F-NaF-PET/CT was performed in conjunction with Alkaline Phosphatase (ALP), Lactate-dehydrogenase (LDH) and Prostatic-Specific Antigen (PSA) values. The mean of SUVmax values were used as a quantitative measure of tumoral burden. Changes in PSA, ALP, LDH from baseline were evaluated, and were defined as increase or decrease of at least 30%. Clinical response was achieved if there was pain reduction using visual analogic scale. Four patients showed a significant reduction in mean SUVmax after 3 cycles of ²²³Ra, and one after 6 cycles. Patients who showed reductions in mean SUVmax after Ra-223 also showed reductions in PSA, ALP and LDH. Four weeks after the last cycle of ²²³Ra all patients had decreased total PSA, ALP and LDH values ≥ 30% also significant improvement on pain. No progress disease was documented after 14 ± 4 weeks. We found slight to moderate decreases in neutrophils and hemoglobin in two patients. We concluded that ²²³Ra plus ADT can be useful in mHSHGPC; the semi-quantitative ¹⁸F-NaF-PET/CT as a method effective to monitor the treatment response. Due to concomitant administration of ADT, ¹⁸F-NaF-PET/CT cannot differentiate whether the findings were due to androgen blockade or the ²²³Ra; nevertheless, data supporting the efficacy of ²²³Ra is the significant improvement on pain.