Sex hormone-binding globulin: a novel marker for nodal metastases prediction in prostate cancer patients undergoing extended pelvic lymph node dissection.

OBJECTIVES: To examine the association between sex hormone-binding globulin (SHBG) and lymph node invasion (LNI) in patients treated with radical retropubic prostatectomy and extended pelvic lymph node dissection (ePLND).
METHODS: The preoperative serum SHBG level was measured in a cohort of 168 consecutive patients (mean age 63.9 years, range 48-77) who underwent radical retropubic prostatectomy with ePLND for clinically localized prostate cancer. Logistic regression models tested the association between the predictors (including prostate-specific antigen, clinical stage, primary and secondary biopsy Gleason grades, and SHBG) and LNI. Logistic regression coefficients were used to calculate the predictive accuracy, which was subjected to 200 bootstrap resamples to reduce overfit bias.
RESULTS: Thirteen patients (7.7%) had LNI. The mean serum SHBG level was significantly greater in the patients with LNI than in those without LNI (50.0 vs 35.1 nmol/L, respectively; P < .001). Univariate analysis indicated that preoperative SHBG was the single most informative predictor of LNI (77.8% vs 71.7% for prostate-specific antigen, 63.9% for clinical stage, and 63.1% and 54.2% for primary and secondary Gleason grade, respectively). On multivariate analysis, preoperative SHBG was still significantly associated with LNI (P < .001), after accounting for the other variables. The addition of preoperative SHBG increased the predictive accuracy of the base model using clinically established predictors from 72.7% to 82.8% (10.1% gain; P < .001).
CONCLUSIONS: The results of this study provide novel evidence that SHBG might serve as a significant multivariate predictor of LNI in patients with prostate cancer undergoing ePLND. The use of preoperative serum SHBG could help to identify patients at risk of LNI who should undergo ePLND.