Combining prostate-specific membrane antigen PET/CT with Memorial Sloan Kettering Cancer Center and Briganti 2012 nomograms enhances lymph node metastasis prediction in prostate cancer patients with a risk above 5.

OBJECTIVE

To evaluate intermediate- to high-risk prostate cancer patients with a predicted lymph node metastasis (LNM) probability over 5%, for whom pelvic lymph node dissection (PLND) is recommended, we assessed the ability of prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) to reduce unnecessary PLND and its effectiveness when integrated with clinical nomograms like the Memorial Sloan Kettering Cancer Center (MSKCC) nomogram and the Briganti 2012 nomogram.

METHODS

A total of 112 patients were selected. Univariate and multivariate logistic analyses were performed. The receiver operating characteristic curve and decision curve analysis were generated for assessing the incremental value of PET/CT diagnosis of LNM combined with the MSKCC and Briganti 2012 nomograms. The reduction in unnecessary PLND across risk thresholds based on the net benefit was further assessed, to evaluate the impact of adding PSMA PET/CT.

RESULTS

Surgical pathology confirmed LNM in 46 (41%) patients. PSMA PET/CT detected all metastases in patients with a 5%-25% LNM probability predicted by the MSKCC nomogram and three of four cases predicted by the Briganti 2012 nomogram in the same range. Multivariate logistic regression identified PSMA PET/CT as a significant predictor of LNM (p<0.001), improving the area under the curve from 0.830 to 0.895 for the MSKCC nomogram (p=0.023) and from 0.808 to 0.889 for the Briganti 2012 nomogram (p=0.009). Decision curve analysis showed that integrating PSMA PET/CT within a 5%-25% risk range reduced unnecessary PLND, with reductions of 10%-26% for the MSKCC nomogram and 7.4%-19% for the Briganti 2012 nomogram, but did not improve predictive efficacy for probabilities above 60%.

CONCLUSION

Integrating PSMA PET/CT with the MSKCC and Briganti 2012 nomograms improves LNM prediction in prostate cancer and significantly reduces unnecessary dissections in patients with a predicted LNM probability between 5% and 25%.