Effect of number of computed tomography (CT) scans during follow-up (FUP) of patients with clinical stage I (CSI) seminoma: A trial-level meta-analysis.

Abstract

564 Background: Despite the overall high cure-rate for patients (pts) with CSI seminoma (sem) regardless of the intervention used, huge discrepancy exists in the number of CT scans that are proposed to pts during FUP period, mainly during active surveillance (AS). The impact of such discrepancy in diagnosing pts with a high-risk relapse was assessed in published literature with a meta-analysis (MA). Methods: We searched for arms of studies of AS or active treatment (AT, adjuvant chemotherapy and radiotherapy) in pts with CSI sem. Meta-analytic techniques were used to pool and compare study level data of AS and AT groups and to study the impact of the number of CT scans (as a continuous variable) during FUP upon the % of pts with CSIII or with IGCCCG intermediate (int) prognosis sem at relapse. Results: 22 studies were analyzed (33 arms, n = 11025 pts). 39.6% had a high-risk sem, 38.8% (n = 4274) underwent AS vs 61.2% (n = 6751) AT. The number of CT scans ≤2y ranged 4-8, and 0-7 for AS and AT groups. Overall, 922 pts experienced a relapse (651 in AS and 271 in AT arms), 73.9% <2y and 22.3% at 2-5y FUP. Statistical modeling showed that the estimated rates of CSIII relapse (6% in AS, 32% in AT group, p = 0.0068) and int prognosis relapse (2% in AS, 11% in AT group, p = 0.0051), were divergent for the two groups. A higher number of CT scans in the first 2 years of FUP tended to reduce the occurrence rate of both endpoints, but failed to reach statistical significance in AS (p = 0.334 for CSIII, unidentifiable for int prognosis relapse), as well as in AT (p = 0.438, p = 0.103). The number of CT scans in 3-5y FUP had an even weaker prognostic effect. Similar trends were observed in AS cohort after adjusting for the CSI risk group. Conclusions: In this trial-level MA we did not find a statistically-significant association between the number of CT scans performed during FUP of CSI sem pts and the diagnosis of high-risk relapses. Huge discrepancy in the total number of CT scans was generally found between arms. In contrast, as expected, the pattern of relapse of CSI sem was different according to the treatment group. Based on these results, there is room for consistently reducing the number of CT scans during FUP of CSI sem pts undergoing AS.