KLK3 and TMPRSS2 for molecular lymph-node staging in prostate cancer patients undergoing radical prostatectomy.

BACKGROUND: Lymph-node (LN) metastasis in prostate cancer (PC) is a main risk factor for tumor recurrence after radical prostatectomy (RP). Molecular analysis facilitates detection of small-volume LN metastases with higher sensitivity than histopathology. We aimed to prospectively evaluate six candidate gene markers for detection of pelvic LN metastases and to determine their ability to predict biochemical recurrence-free survival (bRFS) in patients treated with RP. METHODS: The expression of kallikrein 2, 3, and 4 (KLK2, KLK3, and KLK4), prostate-specific membrane antigen (PSMA), transmembrane serine protease 2 (TMPRSS2) and transient receptor potential cation channel subfamily M member 8 (TRPM8) was assessed using qPCR. We analyzed LNs from 111 patients (intermediate PC, n = 32 (29%); high-risk PC, n = 79 (71%)) who underwent RP and extended pelvic lymph-node dissection without neoadjuvant treatment. RESULTS: Overall, 2411 LNs were examined by molecular and histopathologic examination. Histopathology detected 69 LN metastases in 28 (25%) patients. KLK2 and KLK3 diagnostically performed best and classified all pN1-patients correctly as molecular node-positive (molN1/pN1). The concordance on LN level was best for KLK3 (96%). KLK2, KLK3, KLK4, PSMA, TMPRSS2, and TRPM8 reclassified 27 (24%), 32 (29%), 29 (26%), 8 (7%), 13 (12%), and 23 (21%) pN0-patients, respectively, as node-positive (pN0/molN1). On multivariable cox regression analysis molecular LN status (molN1 vs. molN0) using KLK3 (HR 4.0, p = 0.04) and TMPRSS2 (HR 5.1, p = 0.02) were independent predictors of bRFS. Median bRFS was shorter in patients with only molecular positive LNs (molN1/pN0) for KLK3 (24 months, p = 0.001) and for TMPRSS2 (12 months, p < 0.001) compared to patients with negative nodes (molN0/pN0) (median bRFS not reached). CONCLUSIONS: For diagnostic purposes, KLK3 showed highest concordance with histopathology for detection of LN metastases in PC patients undergoing RP. For prognostic purposes, KLK3 and TMPRSS2 expression were superior to histopathologic LN status and other transcripts tested for molecular LN status. We suggest a combined KLK3/TMPRSS2 panel as a valuable diagnostic and prognostic tool for molecular LN analysis.

Molecular Lymph Node Status for Prognostic Stratification of Prostate Cancer Patients Undergoing Radical Prostatectomy with Extended Pelvic Lymph Node Dissection.

Purpose: Molecular lymph node (LN) analysis using quantitative polymerase chain reaction (qPCR) detects LN metastases with higher sensitivity than histopathology. However, the prognostic role of molecular LN status in prostate cancer patients treated with radical prostatectomy (RP) and extended pelvic LN dissection (ePLND) is unclear. To investigate the association of molecular compared with histopathologic LN status with biochemical recurrence.Experimental Design: Patients with intermediate and high-risk prostate cancer were prospectively enrolled and underwent RP with ePLND, including the obturator, internal, external, and the common iliac region. LNs ≥3 mm were bisected and examined by standard histopathology and qPCR for Kallikrein3 (KLK3) expression. Biochemical recurrence was defined by confirmed postoperative PSA > 0.2 ng/mL.Results: In 111 patients, 2,411 of 3,173 removed LNs were examined by both methods. Histopathology detected 68 LN metastases in 28 (25%) patients. Molecular analysis confirmed elevated KLK3 expression in 65 histopathologic LN metastases of all 28 pN1 patients (pN1/molN1) and additionally reclassified 224 histopathologic negative LNs and 32 (29%) pN0 patients as LN-positive (pN0/molN1).At a median follow-up of 48 months, 52 (47%) patients developed biochemical recurrence. Median biochemical recurrence-free survival was 9 months [95% confidence interval (CI), 0.0-20.1] in pN1/molN1 patients, 24 months (95% CI, 1.7-46.3) in pN0/molN1 patients and was not reached in pN0/molN0 patients (P < 0.001). On multivariable Cox regression analysis, molecular LN status [HR 4.1 (95% CI, 1.9-8.8), P < 0.001] but not histopathologic LN status [HR 1.5 (95% CI, 0.8-3.0), P = 0.198] was confirmed as independent predictor of biochemical recurrence.Conclusions: Molecular LN analysis identified pN0 patients with a high risk of biochemical recurrence and provided superior prognostic information in comparison with histopathology alone. Clin Cancer Res; 24(10); 2342-9. ©2018 AACR.

Topography of lymph node metastases in prostate cancer patients undergoing radical prostatectomy and extended lymphadenectomy: results of a combined molecular and histopathologic mapping study.

BACKGROUND: To determine the anatomic extent of pelvic lymph node dissection (PLND) in prostate cancer (PCa) patients at the time of radical prostatectomy (RP), knowledge about the topography of lymph node (LN) metastases is required. OBJECTIVE: Because small-volume LN metastases may be missed by standard histopathologic examination, we performed an anatomic mapping study combining molecular and histopathologic LN examination in PCa patients treated with RP and extended PLND (ePLND). DESIGN, SETTING, AND PARTICIPANTS: A total of 52 patients with intermediate- (n=15) and high-risk (n=37) PCa underwent RP and ePLND without neoadjuvant treatment. ePLND included dissection of the obturator fossa and the external, internal, and common iliac vessels. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: LNs ≥3 mm in diameter were analysed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) for prostate-specific antigen (PSA) expression and by standard histopathology. Topography of positive LNs was determined descriptively. RESULTS AND LIMITATIONS: Of 1469 dissected LNs (median: 27 LNs per patient), 1186 LNs were ≥3 mm. Molecular LN analysis was positive in 127 LNs of 27 patients (52%) including 32 LNs of 12 patients (23%) with histopathologic positive LNs. Molecular examination was negative in 3 of 35 histopathologic positive LNs (9%). Combining both molecular and histopathologic findings, positive LNs were located in the standard PLND field defined by obturator fossa and external iliac vessels in 71%, along the internal iliac vessels in 16%, and along the common iliac vessels in 13%. Of LN-positive patients, 63% had LN metastases outside the standard PLND field. The internal iliac field was involved in 48% and the common iliac field in 37% of node-positive patients. Notably, internal and common iliac vessels were the only positive regions in 7% and 11% of node-positive patients, respectively. A limitation is the small number of patients included. CONCLUSIONS: These findings underline the enhanced sensitivity of qRT-PCR in comparison with standard histopathology for detection of small-volume LN metastases in PCa patients. Our results support an ePLND including the common iliac vessels, at least up to the ureteral crossing, to optimise nodal staging and to remove LNs potentially harbouring metastases.