Clinical characteristics and treatment strategies of prostate mucinous adenocarcinoma: the multi-center summary of 36 cases

Abstract

Objective To review the clinical characteristics of prostate mucinous adenocarcinoma cases and update literatures , and recommend the corresponding clinical treatment strategy. Methods From October 2010 to March 2018, 36 cases of prostate mucinous adenocarcinoma were involved from 5 urinary centers in China, including 9 cases from Shanghai Changhai Hospital, 4 cases from Wuhan Tongji Hospital, 13 cases from Shanghai Renji Hospitals, 8 cases from the First Affiliated Hospital of Nanjing Medical University, and 2 cases from Sichuan West China Hospitals. The patients′ age were (66.8±7.2) years (53-83 years) and the median PSA was 22.89 ng / ml (2.67-1786 ng / ml). Prostate biopsy confirmed Gleason score 3+ 3 points in 6 cases, 3+ 4 points in 9 cases, 4+ 3 points in 5 cases, 8 points in 11 cases, and 9 to 10 points in 5 cases. According to D′Amico risk stratification, 2 patients were in the low-risk group, 9 in the intermediate-risk group, and 25 in the high-risk group. Eight cases underwent radical retroperitoneal prostatectomy, 13 cases underwent laparoscopic radical prostatectomy, and 12 cases underwent robotic laparoscopic radical prostatectomy. Twenty-three cases underwent pelvic lymphadenectomy, including 12 cases of bilateral obturator lymph node dissection, and 11 cases of bilateral obturator+ intraorbital+ para-vascular para-aortic lymphadenectomy. Results All 36 operations were completed successfully.Twenty-three cases underwent pelvic lymphadenectomy, including 12 of bilateral obturator lymph node dissection, and 11 of bilateral obturator, intraorbital, and para-aortic lymphadenectomy. Pathological examination showed 9 cases of prostate mucinous adenocarcinoma, 26 cases of mucinous adenocarcinoma with acinar adenocarcinoma, and 1 case of mucinous adenocarcinoma with neuroendocrine and immunohistochemical positive of MUC2(+ ). Among 33 cases undergoing radical surgery, the pathological stage of ≤T2b in 12 cases (36.3%), T2c in 7 cases (21.2%), T3a in 7 cases (21.2%), T3b in 6 cases (18.2%), and T4 in 1 case (3.0%). Four cases had positive pelvic lymph nodes and 9 cases had positive margin. The median follow-up period was 26 months (6-48 months). The biochemical recurrence occurred in 6 patients one year after surgery, including 3 cases in the intermediate-risk group and 3 cases in the high-risk group. Six cases with postoperative biochemical recurrence and 19 cases with PSA>0.2 ng/ml after radical or palliative resection underwent adjuvant androgen deprivation therapy(ADT), no postoperative adjuvant radiotherapy or chemotherapy was administered, and 4 cases progressed to castration-resistant prostate cancer. Four cases with CRPC were in the high-risk group and had underwent radical surgery, and the median period progressed to CRPC was 26 months(3-37months)with 2 cases of death. However, there was no significant difference in the rate of biochemical recurrence and the incidence of CRPC in the low-risk group, the intermediate-risk group and the high-risk group. In addition, 2 cases had metastases, with pelvic MRI presenting pelvic multiple nodular mass in one case which was consistent with recurrence and metastasis at the 5th month after radical surgery, and pathological examination presenting the mucinous adenocarcinoma being neurosecretory in another case and mestastasis being detected on glans at the 3rd months after radical surgery. The recovery rate of urinary continience at 6 and 12 months after radical surgery was 86.2%(31/36) and 89.7%(32/36) respectively. Conclusions Prostate mucinous adenocarcinoma is a variant of acinar adenocarcinoma. This study clarifies prostate mucinous adenocarcinoma of Chinese patients with high Gleason scores, advanced pathological stage, variant in prognosis, and prone to recurrence and metastasis. For treatment strategy, the low-risk and intermediate-risk mucinous adenocarcinoma is recommended undergoing radical surgery, and the prognosis maybe good. High-risk mucinous adenocarcinoma could treated with radical surgery or palliative surgery with adjuvant ADT, and most high-risk patients can benefite, with a small number of poor prognosis. Key words: Prostatic neoplasms; Mucinous adenocarcinoma; Biochemical recurrence; Castration-resistant