EAU 2018: The Importance of the Size of Nodal Metastases in Predicting Recurrence of Node-positive Prostate Cancer Patients Treated with Radical Prostatectomy and Extended Pelvic Lymph Node Dissection: Implications For Post-operative Treatment Tailoring

Copenhagen, Denmark (UroToday.com) Patients found to have nodal involvement at the time of radical prostatectomy present a treatment quandary given the different prognostic pathways some of these patients may follow. It is then not surprising that the level one data reported by ECOG 3886 is seldomly followed, which advocated for early hormonal treatment in patients with node positive disease. The group from San Raffaele, aim to assess if the extent of nodal involvement by the tumor could be a better predictor of recurrence than obsolete nodal number and involvement.

The study included 255 node positive prostate cancer (PCa) patients treated with radical prostatectomy (RP) and nodal dissection between 2011 and 2017 at a single center. All patients included had detailed pathological reports describing the number of nodes removed, the number of positive nodes and the maximum diameter of nodal metastasis. Clinical recurrence (CR) was defined as positive imaging during follow-up after the onset of biochemical recurrence (BCR). Multivariable Cox regression analyses tested the impact of maximum nodal involvement on the risk of CR after adjusting for pathologic characteristics. Kaplan-Meier analyses assessed time to CR after stratifying patients according to the number of positive nodes (≤2 vs.>2) and maximum nodal involvement stratified according to the median diameter (≤5 vs.>5 mm).

The median number of nodes removed was 21. The median number of affected nodes were 2, with a median maximum nodal involvement of 5 mm. Approximately 10% of the patients experienced a biochemical recurrence. On multivariate analyses, maximum diameter of nodal involvement was found to be a predictor a predictor of CR (Hazard ratio [HR]: 1.04; p=0.01) after controlling for known pathological variables. The 5-year CR-free survival rates were 92.5% vs 87.4% vs 71.6% vs 67.6% for patients with ≤2 positive nodes and ≤5 mm diameter vs ≤2 positive nodes >5 mm diameter vs >2 positive nodes ≤5 mm diameter vs >2 positive nodes >5 mm diameter (p=0.001).

In summary, the extent of nodal involvement by tumor was an independent predictor of clinical recurrence after controlling for known confounders. The extent of nodal involvement was a superior predictor of recurrence than the absolute number of affected nodes, allowing for better stratification of patients with nodal disease for adjuvant therapies. The study is limited by its retrospective nature and its low numbers. However, it gives insight into the management of a node-positive prostate cancer patients which has become more common with the wide utilization of extended lymphadenectomies.

Speaker: Mazzone, E., Vita-Salute University San Raffaele, Dept. of Urology, Milan, Italy

Written by: Andres F. Correa, MD, Urologic Oncology Fellow, Fox Chase Cancer Center, Philadelphia, PA, at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark
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