Recent research suggests that (68Ga)-prostate-specific membrane antigen (PSMA) PET/CT is helpful diagnostic tool for biochemical recurrence of prostate cancer. This study examined the effectiveness of conventional imaging tests and PSMA PET/CT in patients suspected of having pelvic lymph node (LN) recurrence and compared the results with lymphadenectomy. We also assessed changes in PSA levels before and after surgery to determine the therapeutic effect.

This prospective, non-randomized study involved patients who were previously diagnosed with prostate cancer and had received treatment. During follow-up, patients who suspected biochemical recurrence (PSA ≥ 0.2 ng/mL) and showed lymph node (LN) enlargement on CT or MRI underwent PSMA PET/CT followed by lymphadenectomy. Image interpretation and pathology results were compared, and PSA levels before and after surgery were analyzed.

From January 2023 to April 2024, seven patients underwent lymphadenectomy after PSMA PET/CT imaging, with a median age of 71 (IQR: 67-71). Of these patients, one received proton therapy in 2012, one underwent radiotherapy in 2019 for biochemical recurrence after radical prostatectomy in 2016, and five underwent radical prostatectomy from June 2022 to June 2023 at our hospital. Four patients (57.1%) had a ISUP grade 3, one had a grade of 4, and one had a grade of 5. The tumors of three patients were classified as T2 and four as T3, with LN metastasis confirmed in two patients.The median PSA increase during follow-up was 1.22 (0.78 – 2.38) ng/mL. CT and MRI detected LN enlargement on the right side in five patients and on the left side in two patients. PSMA PET/CT showed no LN uptake in three patients, bilateral LN uptake in one patient, and contralateral LN uptake from CT and MRI scan in one patient. Following pelvic lymphadenectomy, one patient had no confirmation of lymph node metastasis. During a median fifteen months' follow up period, three patients (42.9%) had an increase in PSA and commenced androgen deprivation therapy (ADT). One patient was suspected of having local recurrence and underwent pelvic region radiotherapy and ADT.

The (68Ga)-PSMA PET/CT scan is a valuable diagnostic tool that can complement other imaging tests to improve detection of pelvic lymph node recurrence during follow-up after primary treatment for prostate cancer. Salvage lymphadenectomy can provide diagnostic and therapeutic benefits for selected patients.