Contemporary Treatment Patterns and Outcomes for Clinical Stage IS Testicular Cancer

Abstract

Background: Controversy exists regarding the optimal management strategy for clinical stage IS seminomatous (SGCT) and nonseminomatous germ cell tumors (NSGCT) of the testis.

Objective: To assess contemporary treatment patterns and outcomes for clinical stage IS testicular cancer.

Design, setting, and participants: Using the National Cancer Data Base (2004-2012), we identified 1362 patients with clinical stage IS SGCT and NSGCT of the testis, treated with either adjuvant treatment (AT) or observation.

Outcome measures and statistical analysis: We calculated the annual percent change (APC) to assess treatment trends. Inverse probability of treatment weighting (IPTW)-adjusted Kaplan-Meier curves and Cox regression analyses were used to compare overall survival (OS) between AT and observation groups. Analyses were stratified by histologic type.

Results and limitations: Overall, there were 581 (43%) and 781 (57%) men with SGCT and NSGCT, respectively. Among men with SGCT, the use of AT decreased over the study period (APC=-2.7, 95% confidence interval [CI]: -4.4, -1.1, p=0.001). The 5-yr IPTW-adjusted rates of OS were 99% and 97% in the AT and observation groups, respectively (hazard ratio = 0.36, 95% CI: 0.12, 1.14, p=0.08). Among men with NSGCT, the use of AT remained stable over the study period (APC = +0.8, 95% CI: -0.7, +2.2, p=0.29). The 5-yr IPTW-adjusted rates of OS were 97% and 95% in the AT and observation groups, respectively (HR=0.66, 95% CI: 0.27, 1.61, p=0.36). Limitations include the lack of full treatment details and cancer-specific survival information.

Conclusions: Trends in the use of AT significantly decreased over time for SGCT, while it remained stable for NSGCT. Nonetheless, we report 5-yr OS rates of ≥95% for both histologies without any significant benefit with the use of AT. Further studies are warranted to confirm these findings.

Patient summary: We evaluated treatment trends and outcomes for stage IS testicular cancer. We found that treatment changed over time for seminoma and remained stable for nonseminoma; there was no significant survival benefit in the use of adjuvant treatment versus observation for both seminomatous and nonseminomatous germ cell tumors.

Keywords: Adjuvant; Chemotherapy; Observation; Propensity score; Survival analysis; Testicular neoplasms; Trends.