End‐of‐treatment positron emission tomography/computed tomography complete remission is highly prognostic in nodal peripheral T‐cell lymphoma: An Australasian‐Canadian collaborative study

While end-of-treatment (EOT) imaging after front-line therapy is prognostic in nodal peripheral T-cell lymphoma (PTCL), its subtype-specific significance remains unclear. Retrospective review of patients with nodal PTCL included in the Australasian Lymphoma and Related Diseases Registry and the Princess Margaret Cancer Centre lymphoma database between 2011 and 2024. Progression-free survival (PFS), overall survival (OS), and positive and negative predictive values (PPV/NPV) of an EOT positron emission tomography/computed tomography response were evaluated. We identified 451 patients. Median follow-up was 43.1-months (95% confidence interval [CI] 38.8%-48.3%). Patients achieving an EOT imaging complete remission (CR) had a 36-month PFS of 43.1% (95% CI 34.3%-51.5%). The 36-month OS was significantly higher in patients achieving CR compared with those who did not achieve a CR (73.5% [95% CI 65.3%-80%] vs. 20.9% [95% CI 12.9%-30.2%]; p < 0.001). EOT imaging CR remained prognostic for OS in all nodal PTCL subtypes (p < 0.001). At 36-months, EOT PET demonstrated a PPV of 90% (95% CI 80.5%-96.2%) and a NPV of 43.1% (95% CI 34.3%-51.5%). EOT PET/CT CR is strongly prognostic of OS across nodal PTCL subtypes with a high PPV for predicting death but poor NPV for predicting survival. Outcomes remain poor for patients not achieving a CR, with suboptimal outcomes even in those achieving CR.