Prediction of Lymph Node Involvement with Tumor
Caggianos et al3 developed nomograms for the preoperative prediction of lymph node metastases in patients with clinically localized prostate cancer. Their study was a retrospective, nonrandomized analysis of 7,014 patients treated with radical prostatectomy at six institutions between 1985 and 2000. Excluded were patients who had a history of preoperative androgen ablation therapy, salvage radical prostatectomy, or pretreatment prostate specific antigen greater than 50 ng/ml. As a result, 5,510 patients with complete clinical and pathological information were included in the study. Lymph node metastases were present in 206 patients (3.7%). Preoperative predictors of lymph node metastases consisted of pretreatment PSA, clinical stage (as defined in the 1992 TNM classification schema) and biopsy Gleason score. These predictors were used in logistic regression analysis based nomograms to predict the probability of lymph node metastases.
Pretreatment PSA, biopsy Gleason score, clinical stage and institution represented predictors of lymph node status (p <0.001). The probability that the patient will not have the disease when restricted to all patients who test negative was 99% when the nomogram results predicted 3% or less chance of positive lymph nodes.
Using clinical information, they produced two calibrated and validated nomograms (one of them is illustrated as Nomogram 3), which accurately predict pathologically negative lymph nodes in men with localized prostate cancer who are candidates for radical prostatectomy.
Clinical scenario 3: Using Nomogram 3, a patient with PSA = 10 (53 points), with a T1c tumor (0 points), and a Gleason score of 7 (28 points), (total points = 81) would have only a 3% risk for lymph node involvement with tumor.
3. Cagiannos I, Karakiewicz P, Eastham JA, et al: A preoperative nomogram identifying decreased risk of positive pelvic lymph nodes in patients with prostate cancer. The Journal of Urology, Vol. 170, 1798–1803, November 2003.