Primary tumor size thresholds in stage IA testicular seminoma: Implications for adjuvant therapy after orchiectomy and survival.

Primary tumor size (PTS) is the main prognostic factor for relapse in clinical stage (CS) IA testicular seminoma (T1N0M0S0) and the 8th edition of the Tumor-Node-Metastasis staging system now subcategorizes pT1 tumors into pT1a and pT1b based on PTS (<3 cm and ≥3 cm, respectively). We attempted to assess PTS as a prognosticator for overall survival (OS) in CS IA seminoma and to evaluate the comparative effectiveness of active surveillance (AS) versus adjuvant therapy (AT) in patients with large primary tumors (LPT).

In the National Cancer Database (2004-2014), 2455 (47.7%) and 2685 (52.3%) patients with CS IA seminoma were treated with AS and AT, respectively. AT was defined as the receipt of chemotherapy or radiation within 3 months after orchiectomy. A cut-point analysis was performed to determine the optimal PTS threshold predicting OS at 5 years after orchiectomy. Inverse-probability of treatment weighting (IPTW)-adjusted Kaplan-Meier curves and Cox regression analyses were used to compare OS of patients with LPT (using the optimal PTS cut-point) treated with AS versus AT.

In adjusted analysis, pathologic T-stage (pT1a vs. pT1b) did not predict OS and no OS benefit was noted in pT1b patients treated with AT. The optimal PTS cut-point was 4.5 cm. In multivariable analysis, patients with LPT (≥4.5 cm) had an increased risk of overall mortality (HR = 1.87, P = 0.003). Kaplan-Meier curves revealed that OS was superior in patients with LPT treated with AT (IPTW-adjusted log-rank P = 0.029). In IPTW-adjusted Cox regression analysis, AT was associated with an OS benefit in patients with LPT (HR = 0.59, 95%CI: 0.39-0.91, P = 0.017).

In this National Cancer Database analysis, PTS was a predictor of OS in CS IA seminoma. An OS benefit was noted for individuals with LPT (defined as PTS ≥4.5 cm) managed with AT. These findings may warrant refinement of Tumor-Node-Metastasis staging system.

Urologic oncology. 2019 Nov 05 [Epub ahead of print]

Mounsif Azizi, Charles C Peyton, David C Boulware, Scott M Gilbert, Wade J Sexton

Department of Genitourinary Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL., Department of Biostatistics, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL., Department of Genitourinary Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL; Department of Health Outcomes and Behavior, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL., Department of Genitourinary Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL. Electronic address: .