The study aims to evaluate the prognostic value on the complete metabolic response rate (MCR), the incidence of relapse / progression, the Progression Free Survival (PFS) and the Overall Survival (OS).

• at diagnosis
• after the first cycle of CHOEP (early evaluation)
• at the end of treatment

ALK-positive anaplastic large cell (anaplastic large-cell lymphoma, ALCL) is a rare adult disease for which almost all published studies are retrospective. The overall survival (OS) at 5 years varies from 70 to 87%. A recent international pooled analysis showed that the International Prognostic Index (IPI) had good predictive value for the PFS and the OS.

In children, new prognostic factors have been identified: the titre of circulating anti-ALK antibodies (inverse correlation between the antibody titre and the prognosis), the detection of a NPM-ALK transcript in the blood at diagnosis (minimal disseminated disease, MDD); correlation between MDD positivity and pejorative prognosis) and its minimal residual disease (MRD), and the histological subtype (common versus small cells / lymphohistiocytic).

The predictive value of the oncogenic profile of ALK-positive ALCL and circulating tumor DNA will be studied in this study.

• At diagnosis (before starting treatment):

• Cycle 2 Day 1 (before starting cycle 2 treatment):

• At the end of treatment evaluation:

  40 patients treated with 6 cycles of CHOEP every 3 weeks and 1 lumbar puncture at diagnosis with intrathecal prophylaxis with methotrexate will be included prospectively.

During a 2-year period, relapses / progressions and patient deaths will be monitored for the calculation of the incidence of relapse / progression, progression free survival (PFS) and overall survival (OS).

Inclusion Criteria:

Over 18 years old Diagnosed with Anaplastic large-cell lymphoma ALK+

Planned treatment : 6 cycles of CHOEP 21

Planned lumbar puncture at diagnosis or at the first cycle with intrathecal prophylaxis with methotrexate (15 mg) at the first cycle

Planned interim positron emission tomograph (PET)-scan after 3 cycles of treatment and at the end of treatment according to the center standard of care

Exclusion Criteria:

Involvement of the central nervous system

Intent of Autologous stem-cell transplant in first line

Adult Anaplastic large-cell lymphoma ALK+