BACKGROUND: The purpose of this study was to develop a reliable model to identify clinical Stage I nonseminomatous germ cell tumors (NSGCTs) associated with low risk or high risk for occult retroperitoneal metastasis, so that the model could be used to customize the therapeutic approach for patients with these tumors. The model was to be based on pathohistologic parameters and immunohistochemical expression of proliferation markers, proteases, and adhesion molecules in the primary tumor. METHODS: One hundred forty-nine patients with clinical Stage I NSGCTs underwent retroperitoneal lymphadenectomy and were included in the study. Three to five paraffin embedded, formalin fixed tissue blocks were available from each patient and were analyzed for the following histopathologic features associated with pathologic Stage I or II disease: the presence or absence of vascular invasion (VI), the presence or absence of tunic invasion, and the percentage of each histologic type present in the primary tumor. Immunohistochemical expression of MIB-1, p53, bcl-2, cathepsin D, and E-cadherin was evaluated using a semiquantitative scoring system. Statistical analysis was performed with univariate and multivariate logistic regression models. RESULTS: The percentage of embryonal carcinoma (%EC, P < 0.001) and the presence of VI (P < 0.0001) and tunic invasion (P < 0.002) were the most significant independent risk factors associated with pathologic Stage II disease. A combination of %EC and VI allowed correct prediction of final pathologic stage for 88% of clinical Stage I patients. Cutoff values including both variables identified the correct pathologic stage for 131 of 149 patients (88%). Less than 45% EC and the absence of VI correctly identified pathologic Stage I disease in 91.5% of patients; more than 80% EC and the presence of VI correctly predicted pathologic Stage II in 88%. In univariate analysis, only p53 (P < 0.03) and E-cadherin (P < 0.001) expression were significantly different in the embryonal carcinoma component of pathologic Stage I and II NSGCT. To evaluate prospectively the clinical utility of the new derived cutoff points, the data were applied to 10 consecutive patients with clinical Stage I NSGCT who underwent retroperitoneal lymphadenectomy; pathologic Stage I and II were correctly predicted for 5 of 6 Stage I and 4 of 4 Stage II patients, respectively. CONCLUSIONS: %EC and the presence or absence of VI appear to be reliable prognosticators to identify patients at high risk and low risk for occult retroperitoneal disease. In cases of clinical Stage I NSGCT, p53, bcl-2, MIB-1, cathepsin D, and E-cadherin did not appear to be of prognostic significance. The authors recommend that all patients with clinical Stage I NSGCT have their primary orchiectomy specimens evaluated for %EC and the presence of VI to determine their risk for occult retroperitoneal metastasis.
BACKGROUND: The purpose of this study was to develop a reliable model to identify clinical Stage I nonseminomatous germ cell tumors (NSGCTs) associated with low risk or high risk for occult retroperitoneal metastasis, so that the model could be used to customize the therapeutic approach for patients with these tumors. The model was to be based on pathohistologic parameters and immunohistochemical expression of proliferation markers, proteases, and adhesion molecules in the primary tumor. METHODS: One hundred forty-nine patients with clinical Stage I NSGCTs underwent retroperitoneal lymphadenectomy and were included in the study. Three to five paraffin embedded, formalin fixed tissue blocks were available from each patient and were analyzed for the following histopathologic features associated with pathologic Stage I or II disease: the presence or absence of vascular invasion (VI), the presence or absence of tunic invasion, and the percentage of each histologic type present in the primary tumor. Immunohistochemical expression of MIB-1, p53, bcl-2, cathepsin D, and E-cadherin was evaluated using a semiquantitative scoring system. Statistical analysis was performed with univariate and multivariate logistic regression models. RESULTS: The percentage of embryonal carcinoma (%EC, P < 0.001) and the presence of VI (P < 0.0001) and tunic invasion (P < 0.002) were the most significant independent risk factors associated with pathologic Stage II disease. A combination of %EC and VI allowed correct prediction of final pathologic stage for 88% of clinical Stage I patients. Cutoff values including both variables identified the correct pathologic stage for 131 of 149 patients (88%). Less than 45% EC and the absence of VI correctly identified pathologic Stage I disease in 91.5% of patients; more than 80% EC and the presence of VI correctly predicted pathologic Stage II in 88%. In univariate analysis, only p53 (P < 0.03) and E-cadherin (P < 0.001) expression were significantly different in the embryonal carcinoma component of pathologic Stage I and II NSGCT. To evaluate prospectively the clinical utility of the new derived cutoff points, the data were applied to 10 consecutive patients with clinical Stage I NSGCT who underwent retroperitoneal lymphadenectomy; pathologic Stage I and II were correctly predicted for 5 of 6 Stage I and 4 of 4 Stage II patients, respectively. CONCLUSIONS: %EC and the presence or absence of VI appear to be reliable prognosticators to identify patients at high risk and low risk for occult retroperitoneal disease. In cases of clinical Stage I NSGCT, p53, bcl-2, MIB-1, cathepsin D, and E-cadherin did not appear to be of prognostic significance. The authors recommend that all patients with clinical Stage I NSGCT have their primary orchiectomy specimens evaluated for %EC and the presence of VI to determine their risk for occult retroperitoneal metastasis.