RESUMO
Introduction@#Prostate cancer is the third most common cancer among Filipino males. Ga-68 PSMA PET-CT and Lu-177 PRLT have been introduced in the Philippines for the diagnostics and therapy of prostate cancer. @*Objective@#The aim of this study is to compare treatment outcomes of standard therapy plus Lu-177 PSMA radioligand therapy and standard therapy alone among patients with prostatic cancer status-post castration using Ga-68 PET-CT as an outcome indicator. @*Methodology@#This is an ambispective cohort study on Ga-68 PSMA PET-CT scans performed between January 1, 2018 and July 31, 2021. Serum PSA data taken within one month of the PET-CT scans were also collected when available. The PET-CT images were reviewed by a radiologist for RECIST response, and by a nuclear medicine physician for PERCIST response . @*Results@#A total of 11 participants were included in the study. Six participants (55.5%) received standard therapy, while five participants (45.5%) received Lu-177 PSMA radioligand therapy plus standard therapy. There was no significant difference in the baseline and follow-up CT as shown by all p values > 0.05. A trend towards higher number of participants with non-complete/non-progressive RECIST response was noted in the control group than the treatment group, as well as higher number of participants with progressive or stable disease using the PERCIST response. @*Conclusion@#There were no significant differences noted in the clinical outcomes of participants who received Lu-177 PRLT and those with standard therapy alone. A trend towards decreasing serum PSA, CT and PET measurements were noted among patients given Lu-177 PRLT than those with standard therapy.
Assuntos
Neoplasias da PróstataRESUMO
Background@#PSMA-targeted radiopharmaceuticals have been widely studied for their theragnostic role in prostate cancer and were introduced in the Philippines in 2018. The optimal administered activity of 177Lu-PSMA for targeted endoradiotherapy has not yet been established and is thought to be influenced by several factors, including tumor burden. This study investigates the effect of tumor burden on the normal tissue PSMA uptake among Filipino patients with prostate cancer using its diagnostic counterpart, 68Ga-PSMA I&T @*Methods@#One hundred four patients imaged with 68Ga-PSMA I&T PET/CT in our institution from January 2018 to May 2020 were included. Patients were visually classified into low, medium, and high tumor burden groups. Maximum and mean standardized uptake values (SUVmax and SUVmean) of the lacrimal glands, parotid glands, submandibular glands, kidneys, liver, spleen, and bone were measured and compared among tumor burden groups. @*Results and Conclusions@#68Ga-PSMA I&T uptake in the kidneys, the salivary glands, and the liver, were significantly reduced by approximately 25-50% in patients with high tumor burden. This finding supports the hypothesis that patients with higher tumor load can tolerate higher activity doses of 177Lu-PSMA for endoradiotherapy before developing significant damage to the critical organs. This may serve as a guide towards optimizing and personalizing 177Lu-PSMA I&T administered activity dose for radionuclide therapy
Assuntos
Tomografia por Emissão de Pósitrons , Neoplasias da Próstata , Carga TumoralRESUMO
@#In the Philippines, prostate cancer is the third most common malignancy among men. Over time, it tends to recur and/or progress to metastatic castration-resistant prostate cancer, wherein conventional therapies no longer work. Taking advantage of the high expression of prostate-specific membrane antigen (PSMA) on prostate cancer cells, 68GA- and 177 Lu-PSMA theranostics provides a targeted approach to imaging and therapy. With it's availabity in our country, patients now have an appealing and accessible treatment option. In this paper, we present five cases of metastatic castration-resistant prostate cancer, who have undergone 68Ga-PSMA PET/CT scans and 177Lu-PSMA radioligand therapies in the Philippines, to showcase the usefulness of theranostics in the local setting.