AUA 2022: Can Pelvic Lymph Node Dissection Be Omitted at the Time of Radical Prostatectomy in Patients With a Negative Preoperative 68Ga-PSMA PET/CT? The Importance of Patient Risk Stratification According to Individual Risk of Lymph Node Metastases

(UroToday.com)  The 2022 Annual Meeting of the American Urological Association was host to a podium session of surgical therapies in localized prostate cancer. Dr. Giorgio Gandaglia presented results of his group’s work evaluating the role of 68 Ga-PSMA PET/CT for the pre-operative lymph node staging in patients undergoing a radical prostatectomy.

Dr. Gandaglia began his presentation by noting that the role of PSMA PET/CT in the primary staging for patients with prostate cancer is still debatable. Metaanalyses have demonstrated that in studies where LN involvement prevalence ranged between 5 and 20%, the negative predictive value of PSMA PET/CT remained steadily above 90%. Although previous studies suggested a high NPV in intermediate risk patients, the variation of FN rate according to the prevalence of LN invasion based on pre-operative risk assessment has never been tested.

The aim of this study was to explore the variation of FN rates in a consecutive cohort of men receiving preoperative PSMA PET. The authors identified 90 patients evaluated with 68 Ga-PSMA PET/CT before RP and extended LN dissection between 2019 and 2021 at two referral centers. The main outcome was the FN rate. To test the correlation between the pre-operative LN risk and FN rate, the Briganti nomogram was utilized. The association between the pre-operative LN risk and FN rate was further assessed using logistic regression analyses and the Lowess function.

The baseline patient characteristics are displayed below. Median pre-operative LN involvement risk was 31% (IQR 17-52%). 30 patients had a positive PSMA PET/CT. The FN rate was 22%.

On a per patient basis: PSMA PET/CT showed:

  • 59% sensitivity
  • 81% specificity
  • 78% NPV
  • 63% PPV

On logistic regression analysis, a higher pre-operative LN risk, per the Briganti nomogram, was significantly associated with an increased risk of a positive PET/CT finding (HR 1.36, p=0.02). At Lowess analysis, the NPV progressively increased with higher LNI risk. Notably, FN rates remained equal or lower 10% in patients with a low risk of LNI (< 15%).

AUA2022_Gandaglia_1.png

AUA2022_Gandaglia_2.png

Dr. Gandaglia concluded as follows:

  • The NPV of preoperative PSMA PET/CT is strongly correlated with the pre-operative LN risk.
  • In patients with low LN risk with pre-operative nomograms and negative PSMA PET, the omission of LN dissection could be considered in the light of the very low rate of FN.
  • This evidence reinforces the need to prospectively explore the diagnostic role of PSMA PET compared to LN dissection in patients with intermediate risk disease.

 

 

Presented by: Giorgio Gandaglia, MD, FEBU, Department of Urology, Vita-Salute San Raffaele University, Milan, Italy

Written by: Rashid Sayyid, MD, MSc – Urology Chief Resident, Augusta University/Medical College of Georgia, @rksayyid on Twitter during the 2022 American Urological Association (AUA) Annual Meeting, New Orleans, LA, Fri, May 13 – Mon, May 16, 2022. 

email news signup