Treatment outcome and patterns of relapse following adjuvant carboplatin for stage I testicular seminomatous germ-cell tumour: results from a 17-year UK experience.

ABSTRACT

BACKGROUND: Following inguinal orchidectomy, management options for patients with stage I seminoma include initial surveillance or treatment with adjuvant radiotherapy or chemotherapy. The anticipated relapse rate for patients followed by surveillance alone is ∼15%, with adjuvant treatment this risk is reduced to ∼4%-5% at 5 years. After carboplatin treatment, follow-up strategies vary and there are no validated, predictive markers of relapse. PATIENTS AND METHODS: We conducted a retrospective analysis of all patients presenting with stage I seminoma who received a single cycle of adjuvant carboplatin in South Central England between 1996 and 2013. We report on outcome and the results of univariate and multivariate analysis evaluating possible risk factors for post carboplatin relapse. RESULTS: A total of 517 eligible patients were identified. All underwent nuclear medicine estimation of glomerular filtration rate before treatment with carboplatin (dosed at area under the curve × 7). With a median follow-up of 47.2 months (range 0.4-214 months), 21/517 patients have relapsed resulting in a 5-year estimated relapse-free survival of 95.0% (95% confidence interval 92.8% to 97.3%). Median time to relapse was 22.7 months (range 12.5-109.5 months). Relapse beyond 3 years was rare (4/517; 0.8%). Twenty of 21 (95%) relapsed patients had retroperitoneal lymph node metastases. The majority (16/21; 76%) of patients had elevated tumour markers at relapse. Twenty of 517 (3.9%) patients developed a new contralateral testicular germ-cell cancer. There were no seminoma-related deaths. Tumour size was the only variable significantly associated with an increased risk of relapse. CONCLUSIONS: Overall results for this large cohort of patients confirm an excellent prognosis for these patients with outcomes equivalent to those seen in prospective clinical trials. Increasing tumour size alone appears to be associated with an increased risk of post chemotherapy relapse.