Impact of non-regional lymph node metastases accurately revealed on 18F-PSMA-1007 PET/CT in the clinical management of metastatic hormone-sensitive prostate cancer

Abstract Background: Non-regional lymph node (NRLN) metastases has shown increasing importance in the prognosis evaluation and clinical management of primary metastatic hormone-sensitive prostate cancer (mHSPC). Hence, this study aimed to investigate the concordance rates between 18F-PSMA-1007 PET/CT and conventional imaging (CI) in revealing NRLN metastases, and explore the impact of NRLN metastases on the management of primary mHSPC. Methods: The medical records of 224 patients with primary mHSPC were retrospectively reviewed. Among patients who received 18F-PSMA-1007 PET/CT and CI before initial treatment, the concordance rates between 18F-PSMA-1007 PET/CT and CI were analyzed. The primary endpoint was progression-free survival (PFS), and Cox regression analyses were performed to explore independent predictors of PFS. Results: A total of 99 patients (44.2%) received both 18F-PSMA-1007 PET/CT and CI, the concordance rate in revealing NRLN metastases was only 61.62%, and Cohen’s kappa coefficient was as low as 0.092. Cox regression revealed that androgen deprivation therapy (ADT), N1, high-volume, NRLN and visceral metastases were associated with worse PFS (all P<0.05). In patients with low-volume disease, the median PFS of patients with NRLN metastases was significantly shorter than that of patients without NRLN metastases (19.5 vs. 27.5 months, P=0.01), while the difference between patients with low-volume plus NRLN metastases and high-volume disease was not significant (19.5 vs. 16.9 months, P=0.55). Moreover, early docetaxel chemotherapy significantly prolonged the PFS of these patients compared with ADT alone (20.7 vs. 12.3 months, P=0.008). Conclusion: NRLN metastases could be accurately revealed by 18F-PSMA-1007 PET/CT, which should be considered a high-volume feature, especially concomitant with bone metastases. Furthermore, patients with low-volume plus NRLN metastases may be suitable for more intensive treatment, such as early docetaxel chemotherapy.