Dual-tracer positron emission tomography/computed tomography (PET/CT) with a 68Ga-labelled prostate-specific membrane antigen (PSMA) ligand and 18F-fluorodeoxyglucose (FDG) improves detection of metastatic heterogeneity and burden in patients with nonmetastatic prostate cancer (nmPCa). However, there is limited prospective evidence regarding its impact on the efficacy of stereotactic body radiotherapy (SBRT).
To evaluate metastasis-free survival (MFS) and toxicity after SBRT to dual-tracer PET/CT-detected metastases in patients with nmPCa and early prostate-specific antigen (PSA) progression on androgen deprivation therapy (ADT; PSA ≤2 ng/ml).
Patients were prospectively screened using dual-tracer PET/CT between April 2019 and October 2020. SBRT was recommended for patients with five or fewer nonvisceral metastases (SBRT group). Patients without detectable metastases (N-/M- group) and those who refused SBRT (ADT group) continued to receive ADT. Patients were followed with conventional imaging.
SBRT to each PET/CT-detected metastasis.
Kaplan-Meier methods were used to determine MFS. Toxicity was evaluated using Common Terminology Criteria for Adverse Event v4.0.
Seventy-four consecutive patients were screened. The median PSA and PSA doubling time were 0.59 ng/ml and 4.56 mo, respectively. Overall, 54 patients had metastases and 17 had PSMA-/FDG+ disease. Seven patients were excluded from the MFS analysis, including two with a history of abiraterone treatment and five with more than five metastases. The median follow-up was 21.4 mo. The ADT group had shorter MFS than the SBRT group (11.0 mo vs not reached; hazard ratio [HR] 4.69, 95% confidence interval [CI] 2.92-25.0; p < 0.001) and the N-/M- group (11.0 mo vs not reached; HR 8.78, 95% CI 4.04-40.30; p < 0.001). There was no significant difference in median MFS between the SBRT group and the N-/M- group (p = 0.261). A PSA response >90% was achieved by 86% of patients in the SBRT group. There were no grade ≥3 adverse events after SBRT. The nonrandomized design is the major study limitation.
Dual-tracer PET/CT-guided SBRT delivered superior local control rates in comparison to ADT alone and had minimal toxicity.
We investigated metastasis-targeted radiotherapy for patients with up to five prostate cancer metastases detected with two different radioisotope scans. Our results show that this approach yields promising metastasis-free survival and low toxicity.
European urology oncology. 2022 Mar 15 [Epub ahead of print]
Jian Pan, Yu Wei, Tingwei Zhang, Chang Liu, Xiaoxin Hu, Jinou Zhao, Hualei Gan, Wei Liu, Bin Zhu, Junlong Wu, Beihe Wang, Shaoli Song, Dingwei Ye, Yao Zhu
Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China., Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China; Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Shanghai, China., Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China; Department of Radiology, Fudan University Shanghai Cancer Center, Shanghai, China., Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China; Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China., Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China. Electronic address: .