More micrometastases, more recurrence? The role of qPCR of PSA mRNA in lymph nodes during prostatectomy

Background and objectives Radical prostatectomy is a standard treatment for prostate cancer, yet about 30% of patients experience rising biochemical markers within a decade post-surgery. Pelvic lymph node sampling during prostatectomy assesses potential lymph node metastases, but standard histological assessments, which typically examine only 2–3 tissue sections, often miss occult metastases. This study assesses the effectiveness of qPCR in detecting PSA coding KLK3 mRNA for identifying lymph node metastases post-prostatectomy and explores the correlation between PSA-mRNA and biochemical recurrence. Methods A cohort of 157 patients who underwent radical prostatectomy with lymphadenectomy were examine. On average, 24.7 lymph nodes were removed per patient. Among them, 108 patients reached PSA value below 0.1 ng/ml without receiving additional therapy, and 106 were followed up over a duration of 5.4 years. This subgroup is of particular interest because it allows for the investigation of the correlation between the occurrence of PSA-mRNA in lymph nodes and later biochemical recurrence. Key findings and limitations qPCR of PSA-mRNA identified 47 out of 108 positive cases (43.5%), while histopathological examination only detected 16 out of 108 cases (14.8%). From the followed-up subgroup 37 out of 106 patients (34.9%) experienced biochemical recurrence. It is noteworthy that qPCR yields more positive findings, regardless of the presence of biochemical recurrence. Conclusion and clinical implications The study findings illustrate that qPCR consistently outperforms conventional histology in detecting lymph node metastases, regardless of biochemical recurrence. The hypothesis that qPCR is better at predicting later biochemical recurrence than conventional histology has not been confirmed.