213P - Stage I seminoma testicular cancer: Predictors of relapse and outcomes for adjuvant carboplatin vs active surveillance

Background

Stage 1 (CS1) testicular cancer management has changed dramatically in the last few decades. Seminoma patients now rarely receive adjuvant radiotherapy. Most have adjuvant carboplatin or active surveillance (AS). Tumour size >4cm and rete testis involvement (RTI) have been described as predictive features for relapse but not consistently demonstrated in studies.⁽¹⁾

Methods

Data on CS1 testicular cancer patients presenting to two sites in Western Sydney between 1990 and 2019 were collected. Tumour characteristics including tumour markers, size of primary, LVI and RTI were correlated with relapse.

Results

Total of 322 cases of CS1 seminoma were identified. 222 received adjuvant radiotherapy and were excluded from this analysis. 2 of 33 (6%) who received carboplatin relapsed compared to 11 of 67 (16%) on AS. All relapsed patients were successfully treated with bleomycin, etoposide and cisplatin (BEP) without recurrence. Two of the AS group died of other causes. RFS at 5 years was 82% and OS 99%. In the AS group, the only parameter statistically associated with relapse was LVI with a hazard ratio (HR) of 3.85 (95% CI 1.01, 14.70, p=0.05). beta HCG elevation (HR 3.89 (95% CI 0.92, 16.50, p=0.07), RTI (HR 0.54 (95% CI 0.11, 2.62, p=0.5) and tumour size of >4cm (HR 0.83 (0.21, 3.22, p=0.8) were not statistically associated with relapse.

Conclusions

Patients with CS1 seminoma have good long term outcomes regardless of first-line management choice. In our series, LVI was associated with relapse of seminoma patients on AS and not tumour size >4cm or RTI. These results further support recent findings on the lack of power and consistency of these tumour characteristics in predicting relapse.^{(2, 3)} Given the lack of any strong prognostic factors for relapse and the good long term outcomes of CS1 seminoma patients regardless of initial treatment, we recommend AS as the management of choice to prevent unnecessary toxicities of adjuvant chemotherapy. References: 1. Warde P et al. Prognostic factors for relapse in stage I seminoma managed by surveillance: a pooled analysis. J Clin Oncol. 2002;20(22):4448-52. 2. Boormans et al. Testicular Tumour Size and Rete Testis Invasion as Prognostic Factors for the Risk of Relapse of CS1 Seminoma Testis Patients Under Surveillance: a Systematic Review by the Testicular Cancer Guidelines Panel. Eur Urol. 2018;73(3):394-405. 3. Zengerling F et al. Prognostic factors for tumor recurrence in patients with CS1 seminoma undergoing surveillance-A systematic review. Urol Oncol. 2018;36(10):448-58.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

M. Arasaratnam: Travel/Accommodation/Expenses, educational meeting 2019: Pfizer. H. Gurney: Advisory/Consultancy, Advisory board: BMS; Advisory/Consultancy, Advisory board: Astellas; Advisory/Consultancy, Advisory board: Pfizer; Advisory/Consultancy, Advisory board: MSD; Advisory/Consultancy, Advisory board: Merck; Advisory/Consultancy, Advisory board: Ipsen; Advisory/Consultancy, Advisory board: AstraZeneca. All other authors have declared no conflicts of interest.