Validation of a prediction model for post-chemotherapy fibrosis in nonseminoma patients

OBJECTIVE

To validate Vergouwe's prediction model using the Swedish and Norwegian Testicular Cancer Group (SWENOTECA) RETROP database and to define its clinical utility.

MATERIALS AND METHODS

Vergouwe's prediction model for benign histopathology in post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND) uses the following variables: presence of teratoma in orchiectomy specimen; pre-chemotherapy level of alpha-fetoprotein; β-Human chorionic gonadotropin and lactate dehydrogenase; and lymph node size pre- and post-chemotherapy. Our validation cohort consisted of patients included in RETROP, a prospective population-based database of patients in Sweden and Norway with metastatic nonseminoma, who underwent PC-RPLND in the period 2007-2014. Discrimination and calibration analyses were used to validate Vergouwe's prediction model results. Calibration plots were created and a Hosmer-Lemeshow test was calculated. Clinical utility, expressed as opt-out net benefit (NBopt-out ), was analysed using decision curve analysis.

RESULTS

Overall, 284 patients were included in the analysis, of whom 130 (46%) had benign histology after PC-RPLND. Discrimination analysis showed good reproducibility, with an area under the receiver-operating characteristic curve (AUC) of 0.82 (95% confidence interval 0.77-0.87) compared to Vergouwe's prediction model (AUC between 0.77 and 0.84). Calibration was acceptable with no recalibration. Using a prediction threshold of 70% for benign histopathology, NBopt-out was 0.098. Using the model and this threshold, 61 patients would have been spared surgery. However, only 51 of 61 were correctly classified as benign.

CONCLUSIONS

The model was externally validated with good reproducibility. In a clinical setting, the model may identify patients with a high chance of benign histopathology, thereby sparing patients of surgery. However, meticulous follow-up is required.

Lymphovascular invasion and presence of embryonal carcinoma as risk factors for occult metastatic disease in clinical stage I nonseminomatous germ cell tumour: a systematic review and meta-analysis

Objective

To systematically review the literature on the prognostic value of lymphovascular invasion (LVI) and embryonal carcinoma (EC) for occult metastatic disease in clinical stage I nonseminomatous germ cell tumour (CS I NSGCT).

Materials and methods

The PubMed, Embase (OVID) and SCOPUS databases were searched up to March 2019. Studies reporting on the association between LVI and/or EC and occult metastatic disease were considered for inclusion. The quality and risk of bias were evaluated by the Quality in Prognosis Studies tool.

Results

We screened 5287 abstracts and 207 full‐text articles. We included 35 studies in the narrative synthesis and 24 studies in a meta‐analysis. LVI showed the strongest effect. Pooled rates of occult metastasis were 47.5% and 16.9% for LVI‐positive and LVI‐negative patients, respectively (odds ratio [OR] 4.33, 95% confidence interval [CI] 3.55–5.30; P < 0.001). Pooled rates of occult metastasis were 33.2% for EC presence and 16.2% for EC absence (OR 2.49, 95% CI 1.64–3.77; P < 0.001). Pooled rates of occult metastasis were 40.0% for EC >50% and 20.0% for EC <50% (OR 2.62, 95% CI 1.93–3.56; P < 0.001).

Conclusions

LVI is the strongest risk factor for relapse. The prognostic value of EC is high, but there is no common agreement on how to define this risk factor. Both EC presence and EC >50% have similar ORs for occult metastasis. This shows that the assessment of EC presence is sufficient for the classification of EC.

Prognostic factors for relapse in patients with clinical stage I testicular cancer: protocol for a Danish nationwide cohort study

INTRODUCTION

Approximately one-fourth of patients with clinical stage I testicular germ cell cancer will relapse within 5 years of follow-up. Certain histopathological features in the primary tumour have been associated with an increased risk of relapse. The available evidence on the prognostic value of the risk factors, however, is hampered by heterogeneity of the study populations included and variable reporting of the histopathological features. The aim of this study is to identify pathological risk factors for relapse in an unselected large nationwide cohort of patients with stage I disease.

METHODS AND ANALYSIS

All incident cases of stage I testicular germ cell cancer diagnosed in Denmark between 2013 and 2018 will be identified using the nationwide prospective Danish Testicular Cancer (DaTeCa) database. Archived microscopic slides from the orchiectomy specimens will be retrieved through linkage to the Danish Pathology Data Bank and reviewed blinded to the clinical outcome. The DaTeCa database includes 960 stage I seminoma patients with expected 185 relapses and 480 patients with stage I non-seminoma with expected 150 relapses. A minimum follow-up period of 3 years of all patients will be ensured. Predefined prognostic variables will be investigated with regard to relapse in univariable and multivariable analysis using the Cox proportional hazards model.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Regional Ethics Committee (Region Zealand, Denmark) and the Danish Data Protection Agency. All data will be managed confidentially according to legislation. Study results will be presented at international conferences and published in peer-review journals.