177Lu-prostate-specific membrane antigen (PSMA) is an effective treatment for metastatic castration-resistant prostate cancer. Rarer treatment-related adverse events have not yet been described. Methods: We present case reviews of 2 men with a marked hypocalcemic osteosclerotic response to 177Lu-PSMA-I&T therapy. A clinical dataset of 177Lu-PSMA-I&T therapy was evaluated to estimate the incidence and clinical association with hypocalcemia. Results: Forty-one of the 127 men (32%) had a serum calcium drop, and 6 (5%) developed clinical hypocalcemia during 177Lu-PSMA therapy. The baseline total tumor volume was significantly higher in those who developed hypocalcemia (median, 3,249 cm3 [interquartile range, 1,856-3,852] vs. 465 [interquartile range 135-1,172]; P = 0.002). The mean prostate-specific antigen response in those with hypocalcemia was 78% (SD, 24%). Conclusion: Hypocalcemia may occur in response to 177Lu-PSMA-I&T, particularly with both high-volume bone metastases and a significant prostate-specific antigen response, and may be severe, requiring corticosteroids. Further evaluation of 177Lu-PSMA-induced hypocalcemia is required to better understand mechanisms, optimal treatments, and repercussions from any subsequent osteosclerotic response.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2023 Jun 22 [Epub ahead of print]
Shejil Kumar, Megan Crumbaker, Christopher Harvey, Sarennya Pathmanandavel, Nikieth John, Mina M Swiha, Michelle M McDonald, Roderick Clifton-Bligh, Adrian Lee, Patricia Bastick, William Counter, Andrew Nguyen, Louise Emmett
Department of Endocrinology, Royal North Shore Hospital, Sydney, New South Wales, Australia., Department of Theranostics and Nuclear Medicine, St. Vincent's Hospital, Sydney, New South Wales, Australia., Garvan Institute of Medical Research, Sydney, New South Wales, Australia., Department of Medical Oncology, Royal North Shore Hospital, Sydney, New South Wales, Australia., St. George Hospital, Sydney, New South Wales, Australia., Department of Theranostics and Nuclear Medicine, St. Vincent's Hospital, Sydney, New South Wales, Australia; .