Kinetics of PSMA PET signal after radiotherapy in prostate cancer lesions: A single-center retrospective study

IF 4.9 1区医学 Q1 ONCOLOGY

Radiotherapy and Oncology Pub Date : 2025-03-22 DOI:10.1016/j.radonc.2025.110869

Masatoshi Hotta , Kathleen Nguyen , Pan Thin , Wesley R. Armstrong , Ida Sonni , Andrea Farolfi , Michael Steinberg , Johannes Czernin , Nicholas G. Nickols , Amar U. Kishan , Jeremie Calais

{"title":"Kinetics of PSMA PET signal after radiotherapy in prostate cancer lesions: A single-center retrospective study","authors":"Masatoshi Hotta , Kathleen Nguyen , Pan Thin , Wesley R. Armstrong , Ida Sonni , Andrea Farolfi , Michael Steinberg , Johannes Czernin , Nicholas G. Nickols , Amar U. Kishan , Jeremie Calais","doi":"10.1016/j.radonc.2025.110869","DOIUrl":null,"url":null,"abstract":"<div><h3>Purpose</h3><div>To evaluate the kinetics of prostate-specific membrane antigen (PSMA) PET uptake in irradiated lesions using serial PSMA PET/CT scans.</div></div><div><h3>Methods</h3><div>Patients with prostate cancer who underwent <sup>68</sup>Ga-PSMA-11 PET/CT before (PET1) and after radiotherapy (PET2) were retrospectively included. Percentage changes in SUVmax (ΔSUVmax) of the irradiated lesion were measured. The presence of residual uptake was visually assessed on PET2. When available, follow-up imaging was used for lesion validation. Morphologic or uptake disappearance on follow-up scans was defined as loco-regional complete response (L-CR). Clinical and PET characteristics were compared between lesions with and without residual uptake. An optimal timing for response assessment was calculated by receiver-operating-curve analysis.</div></div><div><h3>Results</h3><div>Eighty-nine patients with 217 irradiated lesions (106 lymph nodes, 85 bone, 21 prostate/prostate bed) receiving ablative radiotherapy were included. Lesion uptake was lower at later time points and was lowest at 9–12 months after radiotherapy. Sixty-eight lesions showed residual uptake on PET2. Residual uptake was more common in lesions imaged at an earlier time point after radiotherapy (median: 7.9 vs. 13.0 months, p = 0.001), lesions in the prostate/prostate bed (p < 0.001), and lesions with higher baseline SUVmax (p = 0.001). Thirty-one residual uptake-positive lesions had available follow-up imaging, of which 24 lesions were confirmed to be L-CR. Risk factors for not achieving L-CR were lesions with prolonged uptake (p = 0.002) and those in the prostate/prostate bed (p = 0.003). The optimal time point for predicting L-CR was 8.6 months.</div></div><div><h3>Conclusions</h3><div>Timing and tumor site affect the PSMA PET signal after radiotherapy, and should be considered when assessing response on post-radiotherapy PSMA PET.</div></div>","PeriodicalId":21041,"journal":{"name":"Radiotherapy and Oncology","volume":"207 ","pages":"Article 110869"},"PeriodicalIF":4.9000,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Radiotherapy and Oncology","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0167814025001641","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ONCOLOGY","Score":null,"Total":0}

引用次数: 0

Abstract

Purpose

To evaluate the kinetics of prostate-specific membrane antigen (PSMA) PET uptake in irradiated lesions using serial PSMA PET/CT scans.

Methods

Patients with prostate cancer who underwent ⁶⁸Ga-PSMA-11 PET/CT before (PET1) and after radiotherapy (PET2) were retrospectively included. Percentage changes in SUVmax (ΔSUVmax) of the irradiated lesion were measured. The presence of residual uptake was visually assessed on PET2. When available, follow-up imaging was used for lesion validation. Morphologic or uptake disappearance on follow-up scans was defined as loco-regional complete response (L-CR). Clinical and PET characteristics were compared between lesions with and without residual uptake. An optimal timing for response assessment was calculated by receiver-operating-curve analysis.

Results

Eighty-nine patients with 217 irradiated lesions (106 lymph nodes, 85 bone, 21 prostate/prostate bed) receiving ablative radiotherapy were included. Lesion uptake was lower at later time points and was lowest at 9–12 months after radiotherapy. Sixty-eight lesions showed residual uptake on PET2. Residual uptake was more common in lesions imaged at an earlier time point after radiotherapy (median: 7.9 vs. 13.0 months, p = 0.001), lesions in the prostate/prostate bed (p < 0.001), and lesions with higher baseline SUVmax (p = 0.001). Thirty-one residual uptake-positive lesions had available follow-up imaging, of which 24 lesions were confirmed to be L-CR. Risk factors for not achieving L-CR were lesions with prolonged uptake (p = 0.002) and those in the prostate/prostate bed (p = 0.003). The optimal time point for predicting L-CR was 8.6 months.

Conclusions

Timing and tumor site affect the PSMA PET signal after radiotherapy, and should be considered when assessing response on post-radiotherapy PSMA PET.

查看原文本刊更多论文

求助全文

约1分钟内获得全文求助全文

来源期刊

Radiotherapy and Oncology 医学-核医学

CiteScore

10.30

自引率

10.50%

发文量

2445

审稿时长

45 days

期刊介绍： Radiotherapy and Oncology publishes papers describing original research as well as review articles. It covers areas of interest relating to radiation oncology. This includes: clinical radiotherapy, combined modality treatment, translational studies, epidemiological outcomes, imaging, dosimetry, and radiation therapy planning, experimental work in radiobiology, chemobiology, hyperthermia and tumour biology, as well as data science in radiation oncology and physics aspects relevant to oncology.Papers on more general aspects of interest to the radiation oncologist including chemotherapy, surgery and immunology are also published.