Depth of response to primary POMB/ACE chemotherapy predicts survival in poor prognosis germ-cell tumours

Most chemotherapy regimens for poor-risk non-seminomatous germ cell tumours (PRGCT) deliver a fixed number of cycles; the role of variable treatment duration aiming for maximal response is unknown. Since the 1970s, we have utilised POMB/ACE chemotherapy for PRGCT, treating until marker normalisation. From mid-1990s, treatment was limited to 7 cycles. We describe outcomes with POMB/ACE for PRCGT, evaluating the association between treatment duration and survival.

We conducted a retrospective cohort study across two UK tertiary cancer centres, identifying patients treated between 1978-2013. Complete response was defined based on normalisation of elevated tumour markers, absence of viable cancer in resection material and resolution of radiological abnormalities. Regression techniques were used to investigate the relationship between therapy duration and outcomes.

132 PRGCT patients completed POMB/ACE with 69.7% (n = 92) alive at 5 years. Number of cycles delivered significantly correlated with recurrence free survival (HR 0.52; 95% CI 0.38-0.71; p < 0.001) and complete biochemical response (OR 1.27; 95% CI 1.10-1.49; p = 0.0018). POMB/ACE discontinuation amongst patients with responding but not normalised tumour markers was associated with worse survival. Study limitations include the retrospective design.

POMB/ACE is highly active for PRGCT. Treatment until maximal biochemical response is associated with superior survival outcomes and warrants further exploration.