Abstract
Purpose
To investigate the association between HER-2 expression and clinicopathological characteristics, biochemical recurrence (BCR) rate and BCR free survival in localized prostate cancer (PCa) patients after radical prostatectomy (RP).
Methods
Between January 2014 and December 2019, 44 patients with pathological confirmed localized PCa who underwent RP were included into this study. According to the expressed level of HER-2 protein, patients were divided into 4 cohorts, cohort-1 (HER-2 0+), cohort-2 (HER-2 1 + or 2+), cohort-3 (HER-2 0 + or 1+) and cohort-4 (HER-2 2+), the clinicopathological and clinical outcomes were analyzed and compared between cohort-1 and cohort-2, cohort-3 and cohort-4, respectively. Univariable, multivariable COX regression model and Kaplan-Meier curves were used to determine the association between HER-2 expression and clinicopathological outcomes including Gleason Score (GS), pathological T (pT) stage, positive surgical margins (PSM) and BCR free survival, respectively.
Results
The median follow-up time was 43 months (IQR 35–49), 20 patients (45.45%) of tumors exhibited HER-2 immuno-reactivity, 14 (31.82%) had HER-2 1+, 6 (13.64%) had HER-2 2 + and 0 (0%) had HER-2 3 + immunostaining. The proportion of PSM in patients with HER-2 0 + was significant lower compared with 1 + or 2+ (41.7% vs 70%, P = 0.045). By using multivariable logistics regression models revealed that HER-2 1 + or 2 + was the independent risk factor strongly associated with higher proportion of PSM (HR, 2.691; 95% CI, 0.619–11.71, P = 0.042). 24 (54.55%) patients developed BCR after surgery, including 8 (33.3%) in cohort-1, 16 (80%) in cohort-2, P = 0.029 while 18 (47.4%) in cohort-3, 6 (100%) in cohort-4, P = 0.025. According to Kaplan-Meier analysis, results showed that in cohort-1, the BCR free survival was significantly longer than in cohort-2, P = 0.000; while in cohort-3, the BCR free survival was significantly longer than in cohort-4, P = 0.000. By using multivariable Cox regression model revealed that HER-2 1+, 2+ (HR, 17.002; 95% CI, 1.378-210.216, P < 0.001), HER-2 2+ (HR, 2.849; 95% CI, 1.234–3.246, P = 0.004) were all significant independent factors associated with BCR after surgery
Conclusion
HER-2 expression was a common phenomenon in PCa, nearly half proportion of localized PCa had HER-2 1 + or 2+, but the cases expressed HER-2 3 + were rare. Cases with HER-2 1 + or 2 + were more likely developed BCR compared with HER-2 0+. The HER-2 expression was closely associated with shorter BCR free survival and higher proportion of PSM, but not associated with GS and pT stage. HER-2 could be considered as a potential method predicting clinical outcomes in patients after RP.