Yuantitative Assessment of the Effectiveness of Radium-223 Chloride Therapy Based on Osteoscintigraphy

Evaluation of the effectiveness of bone metastasis therapy is an important problem in patients with prostate cancer, mainly due to the relationship between bone metastases, survival and quality of life, which necessitates the correct interpretation of treatment response results. The use of additional imaging techniques in clinical practice, along with the assessment of PSA, aims to improve early prognosis of outcome and monitor response to therapy in patients with metastatic CRPC. For effective clinical management of patients receiving Ra-223, radiological response markers are needed to minimize the likelihood of disease progression during therapy and to stratify patients to select subsequent treatment options. Objective : To study the automated bone scanning index (aBSI) as a quantitative radiological assessment of bone scintigraphy results in patients with metastatic castration-resistant prostate cancer (mCRPC) who received systemic radionuclide therapy (RNT) Ra-223. Matreial and Methods : The study included 30 patients who underwent bone scintigraphy before treatment with Ra-223 and aŌer completion of the full course of treatment, laboratory data (PSA, LDH, ALP) obtained before each administration, and the clinical status (Karnovsky index, ECOG) and pain syndrome (VAS) were evaluated. aBSI was obtained at the initial stage and at the end of treatment. Results : The average aBSI level before the start of Ra-223 therapy was 3.5 ц 4.0 (range 0.0ʹ14.7, median 1.9), moderately correlated with PSA ( r с 0.482; р с 0.007) and high with alkaline phosphatase ( r с 0.710; p ф 0.001). AŌer therapy, aBSI — 3.7 ц 4.8 (range 0.1ʹ19.8, median 1.55) was moderately correlated with alkaline phosphatase aŌer therapy ( r с 0.435; р с 0.018). A decrease in the aBSI level was noted in 16/30 (53.3 й). A consistent decrease in LDH and aBSI values in 6/30 (20 й) patients, an increase of 10/30 (30 й). Decrease in both ALP and aBSI in 14/30 (46.7 й) patients, increase in 7/30 (23.3 й), decrease in both PSA and aBSI in 4/30 (13.3 й) patients, increase in 13/30 (43.3 й). A decrease in all parameters was observed in 3/30 (10 й) patients, an increase of 5/30 (16.7 й). An increase in aBSI aŌer completion of therapy was detected in 14/30 (46.7 й), of which 11/14 (78.6 й) were accompanied by an increase in PSA, 4/14 (28.6 й) by an increase in LDH, and 5/14 (35.7 й) by an increase in alkaline phosphatase. Also, in patients who noted an increase in bone pain syndrome, the aBSI increased at the end of therapy, and with a decrease and stabilization, the aBSI decreased ( р с 0 . 0 4 7). Conclusion: Both the initial aBSI index and its change after completion of Ra-223 treatment can be used as a radiological marker of response to assess the effectiveness of Ra-223 therapy in patients with mCRPC.