To observe the clinical effect and safety of regional lymph node dissection in metastatic castration resistant prostate cancer(mCRPC).

The clinical data of 22 patients with mCRPC who underwent regional lymph node dissection in our hospital from August 2015 to May 2021 were retrospectively analyzed. All patients had undergone radical prostatectomy and entered mCRPC, metastatic lymph nodes limited to pelvic or retroperitoneal without other metastasis were determined by PSMA-PET in 5 cases and PSMA-SPECT in 17 cases. The median time from radical surgery to mCRPC was 32 (4-96) months, and the median time from discovery of mCRPC to regional lymph node dissection was 4 (1-43) months. The median PSA before regional lymph node dissection was 4.44 (2.00-22.15) ng/ml. Image of local examination showed pelvic lymph node metastasis in 16 cases, retroperitoneal lymph node metastasis in 3 cases, pelvic together with retroperitoneal lymph node metastasis in 3 cases. Before regional lymph node dissection, 18 patients were treated with drug castration combined with first-generation antiandrogens, and 4 patients were treated with drug castration combined with abiraterone. The lymph node dissection range was determined according to the location of metastatic lymph nodes. Obturator lymph nodes and lymph node metastasis around external iliac and internal iliac vessels: the range of dissection includes fibrous adipose tissue around external iliac vein and internal iliac vein, and obturator lymph adipose tissue. Common iliac and pelvic floor lymph node metastasis: dissect lymphoid adipose tissue around common iliac vessels on the basis of the original dissection range as far as the aortic bifurcation. Retroperitoneal lymph node metastasis: remove all lymph node adipose tissue located between the bifurcation of renal artery and aorta. The PSA remission rate, PSA remission time, surgical complications and other relevant clinicopathological features were analyzed.

Among the 22 cases, 6 cases underwent unilateral pelvic lymph node dissection, 10 cases underwent bilateral pelvic lymph node dissection, 3 cases underwent retroperitoneal lymph node dissection, and 3 cases underwent pelvic and retroperitoneal lymph node dissection at the same time. 19 cases (86.3%) showed positive lymph nodes by pathology. An average of 9.8 (3-29) lymph nodes were dissected in each patient, with an average of 4.1 (0-12) positive lymph nodes. All 22 cases continued to use the previous anti-androgen therapy after lymph node dissection. 17 cases (77.3%) achieved PSA remission after operation, of which 9 cases developed PSA progression, and the median PSA progression time was 12 (2-36) months. Univariate analysis showed that PSA value during radical operation (P=0.029), N stage during radical operation (P=0.057), the number of positive lymph nodes during regional lymph node dissection (P=0.069) and the location of lymph node metastasis during regional lymph node dissection (P =0.005) were related to the progression time of PSA. Postoperative complications: lymphatic leakage in 7 cases; 5 cases of postoperative fever, of which 1 case was confirmed to have pelvic bacterial infection. One patient suffered from massive intra-operative bleeding due to the invasion of blood vessels by metastatic lymph nodes. After timely hemostasis during the operation, the patient returned to the ward and was discharged 6 days later. One case of intestinal obstruction, and 1 case of body surface wound infection. 6 cases of lymphatic leakage healed within 1 month after operation, and 1 case of lymphatic leakage healed within 3 months after operation.

For mCRPC patients with lymph node metastasis which could be surgically removed, regional lymph node dissection may further delay the starting time of posterior drugs, and the complications are relatively controllable.

Prostatic neoplasms; Metastatic; Castration resistant; Regional lymph node dissection; Efficacy; Complications