To determine the prevalence and predictors of mesorectal lymph node (MLN) metastases on prostate-specific membrane antigen (PSMA)-based positron emission tomography/computed tomography (PET/CT) in patients with biochemically recurrent prostate cancer (PCa) following radical therapy.
This was a cross-sectional analysis of all PCa patients with biochemical failure following radical prostatectomy or radiotherapy who underwent an 18 F-DCFPyL-PSMA-PET/CT at The Princess Margaret Cancer Centre between December 2018 and February 2021. Lesions with PSMA scores ≥2 were considered positive for PCa involvement (PROMISE classification). Predictors of MLN metastasis were evaluated using univariable and multivariable logistic regression analyses.
Our cohort consisted of 686 patients. The primary treatment modality was a radical prostatectomy and radiotherapy in 528 (77.0%) and 158 (23.0%) patients, respectively. Median serum PSA level was 1.15 ng/ml. Overall, 384 patients (56.0%) had a positive scan. Seventy-eight patients (11.3%) had MLN metastasis, with 48/78 (61.5%) having MLN involvement as the only site of metastasis. On multivariable analysis, presence of pT3b disease (OR=4.31, 95% CI:1.44-14.2, p=0.011) was significantly associated with increased odds of MLN metastasis, whereas surgical factors (radical prostatectomy versus radiotherapy; performance/extent of pelvic nodal dissection), surgical margin positivity, and Gleason Grade were not.
11.3% of PCa patients with biochemical failure have MLN metastasis on18 F-DCFPyL-PET/CT. pT3b disease is associated with 4.31-fold significantly increased odds of MLN metastasis. These findings suggest alternate drainage routes for PCa cells, either via alternate lymphatic drainage from the seminal vesicles themselves or secondary to direct extension from posteriorly located tumors invading the seminal vesicles.
BJU international. 2023 Jul 11 [Epub ahead of print]
Rashid K Sayyid, Rui Bernardino, Zizo Al-Daqqaq, Raj Tiwari, Jessica Cockburn, Shagana Vijayakanthan, Ricardo Leão, Yazan Qaoud, Mohamad Baker Berjaoui, Ur Metser, Alejandro Berlin, Neil E Fleshner
Division of Urology, Department of Surgical Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto., Temerty Faculty of Medicine, University of Toronto, Toronto., University of Galway School of Medicine, Galway, Ireland., Faculty of Medicine of the University of Coimbra, Coimbra, Portugal., Joint Department of Medical Imaging, University Health Network, Toronto., Department of Radiation Oncology, University of Toronto; Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto.