Treatment strategies and outcome in relapsed peripheral T-cell lymphoma: results from the Netherlands Cancer Registry.

Optimal treatment in patients with refractory or relapsed peripheral T-cell lymphomas (R/R T-NHL) is unknown. In this population-based study, outcome in R/R PTCL not otherwise specified (PTCL NOS), angioimmunoblastic T-cell lymphoma (AITL) and ALK+ and ALK- anaplastic large cell lymphoma (ALCL) was evaluated. Patients with PTCL NOS, AITL, ALK+ ALCL and ALK- ALCL (≥18 years) diagnosed in 2014-2019 were identified using the Netherlands Cancer Registry. Endpoints were overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). The 2-year PFS of 821 patients was 57%. Among 311 patients with a relapse, 243 received second-line treatment: 44% salvage chemotherapy, 20% brentuximab vedotin (BV) and 36% other treatment. In third-line, BV was most commonly used (38%). ORR following second-line treatment was 47%. Two-year PFS and OS after relapse were 25% and 34%, respectively. Risk of second relapse was negatively affected by early relapse (<12 months post-diagnosis), while BV reduced this risk compared to salvage chemotherapy (HR 0.55; 0.35-0.87; p=0.01). Reduced risk of relapse was independent of histological subtype. The best outcomes were observed for patients treated with salvage chemotherapy receiving consolidative autologous and allogeneic stem cell transplantation (SCT) (2-year OS 68%), patients treated with BV achieving a second complete remission (2-year OS 74%) and patients with allogeneic SCT (2-year OS 60%). The risk of second relapse was significantly lower for R/R T-NHL patients treated with BV compared to patients treated with salvage chemotherapy, and this was irrespective of subtype. Therefore, the use of salvage chemotherapy for R/R T-NHL patients is challenged.

A population-based study of transformed marginal zone lymphoma: identifying outcome-related characteristics.

Histological transformation of marginal zone lymphoma (tMZL) into diffuse large B-cell lymphoma is associated with poor outcomes. Clinical characteristics associated with transformation risk and outcome after transformation are largely unknown due to scarcity of data. In this population-based study, competing risk analyses were performed to elucidate clinical characteristics associated with developing transformation among 1793 MZL patients using the Netherlands Cancer Registry. Cox regression analyses were performed to elucidate clinical characteristics associated with risk of relapse and mortality after transformation. Transformation occurred in 75 (4%) out of 1793 MZL patients. Elevated LDH and nodal MZL subtype at MZL diagnosis were associated with an increased risk, and radiotherapy with a reduced risk of developing tMZL. Most tMZL patients received R-(mini)CHOP (n = 53, 71%). Age >60 years and (immuno)chemotherapy before transformation were associated with an increased risk of relapse and mortality after transformation. Two-year progression-free survival (PFS) and overall survival (OS) were 66% (95% CI 52-77%) and 75% (95% CI 62-85%) for R-(mini)CHOP-treated tMZL patients, as compared to a PFS and OS both of 41% (95% CI 19-63%) for patients treated otherwise. Our study offers comprehensive insights into characteristics associated with transformation and survival after transformation, thereby optimizing guidelines and patient counseling.