Pathological risk factors for metastatic disease at presentation in testicular seminomas with focus on the recent pT changes in AJCC TNM eighth edition

Management of clinical stage (CS) 1 testicular seminoma is controversial. Treatment choice is based on a number of pathological risk factors. However, they have been inconsistently associated with risk of metastatic disease. The eighth edition of the American Joint Committee on Cancer Tumor-Node-Metastasis staging system has separated pT1a and pT1b tumors according to a 3-cm size cutoff and upstaged invasion of hilar soft tissue and epididymis as pT2. We investigated pathological predictors of metastatic disease at presentation in 332 testicular seminomas. Age, tumor size, invasion of vessels, hilar soft tissue, rete testis, epididymis, spermatic cord, tunica vaginalis and tumor at spermatic cord margin were assessed and correlated with CS at presentation. A total of 290 (87%) tumors were CS 1; 42 (13%) were CS 2/3. Median patient age of CS 1 was 36 years (20-81); that of CS 2/3 was 36 years (26-63). Mean tumor size of CS 1 was 38 mm (5-95 mm); that of CS 2/3 was 54 mm (8-95 mm). On univariate analysis, lymphovascular invasion (P = .044), epididymal invasion (P = .009) and tumor size (P = .0001) were associated with higher CS. On multivariate analysis, tumor size (P = .0001) and epididymis invasion (P = .023) remained significant. Optimal tumor size cutoff was 4.25 cm. We conclude that tumor size and epididymal invasion are the strongest predictors of metastatic disease at presentation. The results validate changes in American Joint Committee on Cancer Tumor-Node-Metastasis staging eighth edition but suggest a tumor size of 4 cm as better cutoff value.