Stage II testicular seminoma is highly curable with radiotherapy or multi-agent chemotherapy (MACT). These modalities have not been compared in a randomised manner.
Using the US National Cancer Data Base, we identified 2437 stage II seminoma patients (IIA = 960, IIB = 812, IIC = 665) treated with orchiectomy and either radiotherapy or MACT from 1998 to 2012. Factors affecting treatment modality (radiotherapy versus MACT) were studied using multivariable logistic regression. Propensity scores for treatment selection were incorporated into multivariable Cox regression analyses of overall survival.
The median follow-up was 65 months (interquartile range 34-106). Rates of radiotherapy utilisation were: IIA = 78.1%, IIB = 54.4%, IIC = 4.2%. Rates of MACT utilisation were: IIA = 21.9%, IIB = 45.6%, IIC = 95.8%. For both IIA and IIB patients, later year of diagnosis, academic treatment facility and pathological confirmation of lymph node positivity were associated with increased utilisation of MACT. Also predictive for preferential utilisation of MACT were comorbidity score ≥ 1 and non-private insurance for IIA patients and T stage ≥ 2 for IIB patients. For IIA patients, survival was improved with radiotherapy compared with MACT with a 5 year survival of 99.0% (95% confidence interval 98.2-99.8) versus 93.0% (95% confidence interval 89.0-97.0). This advantage persisted on propensity-adjusted multivariate analysis (hazard ratio 0.28; 95% confidence interval 0.09-0.86; P = 0.027). For IIB patients, 5 year survival was 95.2% (95% confidence interval 92.8-97.6) for radiotherapy and 92.4% (95% confidence interval 89.2-95.6) for MACT (Log-rank P = 0.041), with no significant difference on multivariable analysis.
Radiotherapy is associated with improved survival over MACT for IIA patients, with no significant survival difference for IIB patients.
Clinical oncology (Royal College of Radiologists (Great Britain)). 2016 Mar 13 [Epub ahead of print]
S M Glaser, J A Vargo, G K Balasubramani, S Beriwal
Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA., Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA., Department of Epidemiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA., Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA. Electronic address: .