Posttherapeutic Critical Organ Dosimetry of Extensive 177Lu-PSMA Inhibitor Therapy With Metastatic Castration-Resistant Prostate Cancer

Abstract

Purpose 177Lu-PSMA inhibitor peptide receptor radioligand therapy (RLT) is playing an increasing role in metastatic castration-resistant prostate cancer. We aimed to estimate the absorbed radiation doses for critical organs (eg, kidneys, parotid glands, submandibular glands, and lacrimal glands) of patients treated with 4 to 6 cycles by 177Lu-PSMA inhibitor RLT, retrospectively, and to evaluate the findings extensively in order to determine the critical organ radiation-absorbed limitations and the number of prospective RLT. Materials and Methods A total of 51 cycles 177Lu-PSMA inhibitor RLT in 10 patients was analyzed. Therapies have been applied in 4 to 6 cycles with 8 to 10 weeks' intervals. Dosimetric estimates of kidneys, parotid glands, submandibular glands, and lacrimal glands have been calculated based on MIRD scheme pamphlet no. 16. Regions of interest were drawn with GE Xeleris Functional Imaging Workstation. OLINDA/EXM 1.1 simulation software was used to calculate radiation-absorbed doses. Results Mean radiation-absorbed doses were 0.70 ± 0.24 Gy/GBq for kidneys, 1.34 ± 0.78 Gy/GBq for parotid glands, 0.94 ± 0.45 Gy/GBq for submandibular glands, and 2.28 ± 1.29 Gy/GBq for lacrimal glands. Conclusions Due to the critical target organ risks and the optimal therapy doses, patient-specific dosimetry is a deterministic factor in radionuclide therapy. Even when the absorbed kidney doses were above the ICRP critical dose limits in patients who had 4 to 6 cycles of therapy, mortality due to nephrotoxicity has not been observed. Mild increased tolerated radiation dose is acceptable for the patient groups with very low survival rate.

Lutetium-177-PSMA-617 in Low-Volume Hormone-Sensitive Metastatic Prostate Cancer: A Prospective Pilot Study

“…This also applies to the kidneys (radiation dose in the present study: median 4.3 Gy, range 3.1-6.1 Gy), which has an organ limitation dose of 40 Gy according the recent 177 Lu-PSMA guideline (28). The dosimetry outcomes in the present study are comparable to the results in high-volume mCRPC patients implying that the sink-effect with unfavorable radioligand distribution to the organs at risk in low-volume disease is of less concern than anticipated (29)(30)(31). Nonetheless, long term toxicities, which could develop over time, need evaluation in following studies.…”

RETRACTED ARTICLE: MAGE-C2/CT10 promotes growth and metastasis through upregulating c-Myc expression in prostate cancer

“…Prostate cancer (PC) is the most common reproductive cancer in men and the third leading cause of cancer death among men worldwide [1]. Although treatment options such as radical prostatectomy and radiotherapy can successfully cure most patients, about 30-40% of patients will relapse, which is the main factor affecting the survival of patients with prostate cancer [2]. In the case of advanced prostate cancer, due to its high metastasis, chemoradiotherapy and surgical resection are not effective, further increasing the mortality rate [3].…”

PT-BR: Radioterapia PSMA-ligante dirigida com Lutécio 177 como um tratamento para câncer de próstata resistente a castração: uma revisão sistemática

“…Other reported side effects include mild xerophthalmia 10 , fatigue 10,18,26,27,29 and nausea that responds well to medication 11,15,18,29 . 177 Lu-PSMA-617 did not lead to more severe forms of nephrotoxicity (grades 3-4), as measured by creatinine blood levels and glomerular filtration rate 10,26,27,29,30 , despite the kidney being one of the organs which most receives radiation.…”

“…Generally speaking, there are few severe side effects of treatment with 177 Lu-PSMA-617. The most frequently reported one was mild to moderate xerostomia, usually reversible 6,15,16,18,19,26,27,29,30 . This can be explained by radiopharmaceutical uptake by salivary glands, as pointed out in dosimetry.…”