6.1. Risk factors for metastatic relapse in clinical stage I testicular cancer
With stage I seminoma, primary testicular tumour size and stromal invasion of the rete testis have been identified as predictors for relapse in a pooled analysis of retrospective data . Absence of both factors indicates a low risk of recurrence (6%) . Whilst the original analysis was not supported by a further retrospective report , some prospective series [32-34] support the prognostic significance of tumour size and stromal invasion of the rete testis. Two SRs have assessed the prognostic value of these risk factors [35,36]. While tumour size (continuous or dichotomised) and rete testis invasion are associated with a higher risk of relapse, both SRs highlighted the low quality of the studies included and that the level of evidence is too low to recommend the use of these pathological risk factors to drive adjuvant treatment decisions [35,36].
For non-seminoma stage I, invasion of the primary tumour into blood or lymphatic vessels, LVI, is the most reliable single predictor of occult metastatic disease [37-39]; while interobserver agreement is limited, immunohistochemistry might improve detection . The percentage of embryonal carcinoma within a tumour may enhance the PPV and NPV of LVI , but there is no definitive prognostic cut-off for percentage . Risk of relapse at five years with LVI is 50%, compared to 15% without LVI. The significant prognostic pathological risk factors for stage I TC are listed in Table 5.
Table 5: Pathological risk-factors for occult metastatic disease in stage I testicular cancer
• Pathological risk-factors
• Tumour size
• Invasion of the rete testis
• Lympho-vascular invasion in