Detection of pelvic lymph node micrometastasis by real-time reverse transcriptase polymerase chain reaction in prostate cancer patients after hormonal therapy.

OBJECTIVE: To determine the feasibility of prostatic-specific antigen (PSA) mRNA and prostatic-specific membrane antigen (PSMA) mRNA measurement in detection of pelvic lymph node (PLN) micrometastasis for prostate cancer (PCa) after hormonal therapy (HT).
METHODS: Fifty-four patients diagnosed as high risk localized PCa were given HT for 3 months before radical prostatectomy. Under bipedal lymphangiography, a needle was punctured into involved lymph nodes (LN) and aspirated lymphatic fluid was obtained preoperatively. The expression of PSA mRNA and PSMA mRNA in aspirated fluid was assessed by a fully quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR) and also in LN specimens from pelvic lymphadenectomy during prostatectomy.
RESULTS: Median follow-up was 36 months (range 18-58 months). Without histological evidence of PLN metastasis, twelve patients showed positive PSA and/or PSMA mRNA expressions and regarded as having micrometastases to PLNs. Biochemical recurrence (BCR) rate and interval between prostatectomy and BCR in patients with micrometastases (group B) were not significantly different to histologically proven PLN metastatic patients (group A) (58.3 vs. 83.3 %, P = 0.26; 10.9 vs. 9.2 months, P = 0.29, respectively), but significantly different to those with no PLN involvement (group C) (58.3 vs. 11.1 %, P = 0.002; 10.9 vs. 21.3 months, P < 0.001, respectively). Kaplan-Meier analysis showed both groups A and B had significantly lower non-BCR rate than group C (P < 0.001, P < 0.001, respectively).
CONCLUSIONS: For PCa patients receiving HT, measurement of PSA mRNA and PSMA mRNA in aspirated PLN fluid by real-time RT-PCR could effectively detect PLN micrometastases without surgical intervention.