Robot-Assisted Radical Prostatectomy: Concordance and Correlation Between Preoperative Positron Emission Tomography-Computed Tomography With Prostate-Specific Membrane Antigen (PET-CT PSMA) and Final Histopathological Report.

BACKGROUND

Positron emission tomography-computed tomography with prostate-specific membrane antigen (PET-CT PSMA) has revolutionized the preoperative staging of prostate cancer, particularly for assessing seminal vesicle and lymph node invasion. However, its correlation and agreement with definitive histopathology remain unclear.

OBJECTIVE

The study aimed to evaluate the diagnostic performance, correlation, and agreement between PET-CT PSMA and final histopathological findings for seminal vesicle and lymph node invasion in patients undergoing robot-assisted radical prostatectomy.

METHODS

This retrospective, single-center study included 194 patients who underwent PET-CT PSMA and radical prostatectomy. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were calculated. Correlation (Spearman's rho) and agreement (kappa coefficient) between PET-CT PSMA and final histopathology were analyzed.

RESULTS

Seminal vesicle invasion was detected in 11.9% of cases by histopathology and 12.4% by PET-CT PSMA, while lymph node invasion was reported in 4.8% and 10.3%, respectively. PET-CT PSMA exhibited high specificity (91.23% for seminal vesicles, 92% for lymph nodes) and high NPVs (91.76% and 96.84%, respectively), but low sensitivity (39.13% and 40%) and low PPV for lymph nodes (20%). Correlation between PET-CT PSMA and histopathology was low for seminal vesicle invasion (rho = 0.298; p = 0.0001) and lymph node invasion (rho = 0.232; p = 0.017). Agreement was also poor for seminal vesicle invasion (kappa = 0.298) and lymph node invasion (kappa = 0.217).

CONCLUSION

PET-CT PSMA demonstrates high specificity and NPV but low sensitivity, correlation, and agreement with final histopathology. While useful for ruling out disease, its positive findings should be interpreted with caution.