In the phase III TRISST trial reported in the Journal of Clinical Oncology, Joffe et al found that surveillance with magnetic resonance imaging (MRI) was noninferior to computed tomography (CT) in detecting advanced relapse in patients with stage I testicular seminoma who had undergone orchiectomy with no planned adjuvant therapy. A reduced surveillance schedule was also found to be noninferior to a standard schedule.
As stated by the investigators, “Survival in stage I seminoma is almost 100%. CT surveillance is an international standard of care, avoiding adjuvant therapy. In this young population, minimizing irradiation is vital. The Trial of Imaging and Surveillance in Seminoma Testis (TRISST) assessed whether MRIs or a reduced scan schedule could be used without an unacceptable increase in advanced relapses.”
In the open-label multicenter 2 × 2 factorial trial, 699 patients (mean age = 39 years) were randomly assigned between 2008 and 2014 to undergo surveillance with seven CTs (n = 169), seven MRIs (n = 167), three CTs (n = 166), or three MRIs (n = 167). The seven scans were performed at 6, 12, 18, 24, 36, 48, and 60 months; the three scans were performed at 6, 18, and 36 months. The primary outcome measure was 6-year incidence of Royal Marsden Hospital stage ≥ IIC relapse (> 5 cm). The noninferiority criterion was to exclude increases ≥ 5.7% with MRI vs CT and with three scans vs seven scans.
Key Findings
Over a median follow-up of 72 months, any relapse occurred in 82 patients (12%), including 41 in the MRI group and 41 in the CT group. Overall, 76% and 73% of relapses were detected at the scheduled CT and MRI scans, respectively.
Stage ≥ IIC relapse occurred in 10 patients (1.5%), with 2 (0.6%) found in the MRI group and 8 (2.6%) in the CT group. Noninferiority of MRI was demonstrated, with a decrease of 1.9% and 90% confidence interval of –3.5% to –0.3%. Relapse with tumor size ≥ 3 cm occurred in 24 patients (3.6%), with 11 (3.4%) found in the MRI group and 13 (4.1%) in the CT group; noninferiority was shown, with a decrease of 0.8% and 90% confidence interval of –3.3% to 1.7%.
Stage ≥ IIC relapse was more frequent in the three-scan group (9 cases, 2.8%) than the seven-scan group (1 case, 0.3%); however, noninferiority of three scans was shown, with a 2.5% increase and 90% confidence interval of 1.0% to 4.1%. Four of nine relapses could potentially have been detected earlier with seven instead of three scans. Relapse with tumor size ≥ 3 cm was also more common with three scans (15 cases, 4.7%) than seven scans (9 cases, 2.7%), but noninferiority was maintained with a difference of 2.0% and 90% confidence interval of –0.4% to 4.4%.
Five-year overall survival was 99%, with no tumor-related deaths.
The investigators concluded, “Surveillance is a safe management approach—advanced relapse is rare, salvage treatment successful, and outcomes excellent, regardless of imaging frequency or modality. MRI can be recommended to reduce irradiation; and no adverse impact on long-term outcomes was seen with a reduced schedule.”
Fay H. Cafferty, PhD, of the MRC Clinical Trials Unit at UCL Institute of Clinical Trials & Methodology, London, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was funded by Cancer Research UK and Medical Research Council Clinical Trials Unit at UCL. For full disclosures of the study authors, visit ascopubs.org.
