Background: The purpose of the study was to prospectively evaluate the incidence of nodal OCM assessed using SS, IHC, and RT-PCR in prostate cancer patients compared with the standard pathological evaluation (SPE), and to evaluate short-term oncological outcomes of patients with OCM.
Patients and methods: Fifty-four consecutive patients with intermediate- or high-risk prostate cancer treated with radical prostatectomy and extended pelvic LN dissection comprised the study population (StP). The central sections with the largest diameter of each LN of the StP and a matched-pair population (MpP) with identical characteristics as the StP were used to assess the improved detection rate of OCM. Pathological characteristics and biochemical recurrence-free survival were assessed according to the presence of macroscopic or OCM.
Results: A total of 1064 LNs were processed in the 54 patients of the StP, with 11 (20.4%) patients with evident metastases at SPE and 7 with OCM (13.0% additional patients); the percentage of positive patients improved from 16.6% (18 of 108) of the MpP to 33.3% (18 of 54) of the StP (16% additional patients). The mean diameter of the 10 additional LNs with OCM found at SS only and of the 6 additional LNs found at IHC only was significantly lower than the mean diameter of the 28 metastases found at routine pathologic examination (RPE) (P < .0001). Patients with OCM showed risk of biochemical recurrence similar to patients with no LN metastases (P = .008).
Conclusion: SS, IHC, and RT-PCR can detect a not negligible percentage of OCM missed at RPE. Patients with OCM showed short-term oncological outcomes more similar to those with macroscopic metastases. Longer follow-up studies considering cancer-specific survival are needed.
Keywords: Lymph node micrometastases; Pathological examination; Pelvic lymph node dissection; RT-PCR; Radical prostatectomy.
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