Aggressive T-cell lymphomas are a heterogeneous group of mature T-cell and natural killer (NK)-cell neoplasms characterized by rapid progression, aggressive clinical behavior, and generally poorer outcomes compared with most B-cell lymphomas. These malignancies are relatively rare and are often diagnosed at advanced stages with extranodal involvement.

Common subtypes include:

• Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS)

• Angioimmunoblastic T-cell lymphoma (AITL)

• Anaplastic large cell lymphoma (ALCL)

• Enteropathy-associated T-cell lymphoma (EATL)

• Extranodal NK/T-cell lymphoma

• Hepatosplenic T-cell lymphoma

Aggressive T-cell lymphomas are generally more aggressive than diffuse large B-cell lymphoma (DLBCL) and require prompt treatment.

Epidemiology

Aggressive T-cell lymphomas account for approximately 10–15% of all non-Hodgkin lymphomas worldwide.

Epidemiological features include:

• More common in adults than children

• Slight male predominance

• Higher prevalence in Asia and parts of Africa

• Frequently present with advanced-stage disease

• Often associated with poorer prognosis than B-cell lymphomas

Risk factors

Viral infections

Associated viral infections include:

• Human T-cell lymphotropic virus type 1 (HTLV-1)

• Epstein-Barr virus (EBV)

• Human immunodeficiency virus (HIV)

Immunodeficiency states

Including:

• HIV infection

• Post-transplant immunosuppression

• Congenital immunodeficiency disorders

Autoimmune disorders

Including:

• Rheumatoid arthritis

• Sjögren syndrome

• Systemic autoimmune diseases

Chronic immune stimulation

Persistent antigenic stimulation may contribute to lymphomagenesis.

Genetic abnormalities

Various chromosomal and molecular abnormalities are implicated in disease development.

Pathophysiology

Aggressive T-cell lymphomas arise from mature post-thymic T lymphocytes or NK cells.

The disease process involves:

1. Malignant transformation of mature T cells

2. Uncontrolled proliferation

3. Lymph node and extranodal infiltration

4. Bone marrow involvement

5. Dissemination to distant organs

Common sites of involvement include:

• Lymph nodes

• Bone marrow

• Skin

• Liver

• Spleen

• Gastrointestinal tract

Many subtypes exhibit resistance to conventional chemotherapy compared with B-cell lymphomas.

Clinical presentation

Most patients present with rapidly progressive disease and generalized symptoms.

Symptoms

Constitutional symptoms

• Fever

• Drenching night sweats

• Unintentional weight loss

• Fatigue

Lymph node symptoms

• Painless cervical lymphadenopathy

• Axillary lymphadenopathy

• Inguinal lymphadenopathy

Extranodal symptoms

• Abdominal pain

• Diarrhoea

• Gastrointestinal bleeding

• Skin lesions

• Respiratory symptoms

Advanced disease symptoms

• Progressive weakness

• Loss of appetite

• Recurrent infections

• Symptoms related to organ infiltration

Clinical signs

Lymphatic system

• Generalized lymphadenopathy

• Bulky nodal disease

Abdominal examination

• Hepatomegaly

• Splenomegaly

• Abdominal masses

Skin findings

• Nodules

• Plaques

• Erythematous lesions

• Ulcerative lesions

General findings

• Cachexia

• Pallor

• Reduced performance status

Differential diagnosis

• Diffuse large B-cell lymphoma

• Hodgkin lymphoma

• Chronic lymphocytic leukemia

• Tuberculous lymphadenitis

• Infectious mononucleosis

• Reactive lymphadenopathy

• Acute leukemia

• Metastatic carcinoma

Diagnostic criteria

Aggressive T-cell lymphoma should be suspected in patients presenting with:

• Persistent or progressive lymphadenopathy

• B symptoms

• Hepatosplenomegaly

• Extranodal disease

• Rapid clinical deterioration

Definitive diagnosis requires:

• Histopathological examination

• Immunohistochemistry

• T-cell immunophenotyping

Investigations

Laboratory investigations

Full blood count (FBC)

To assess:

• Anaemia

• Leukopenia

• Thrombocytopenia

Lactate dehydrogenase (LDH)

Elevated levels often indicate high tumour burden.

Renal function tests

• Urea

• Creatinine

• Electrolytes

Liver function tests

• AST

• ALT

• Bilirubin

• Albumin

• Alkaline phosphatase

Serum calcium

May be elevated in advanced disease.

Uric acid

Useful for tumour lysis syndrome risk assessment.

Viral screening

• HIV

• Hepatitis B

• Hepatitis C

• HTLV-1 where available

Imaging investigations

Chest X-ray

To assess mediastinal involvement.

CT scan of chest, abdomen and pelvis

For staging and assessment of extranodal disease.

PET/CT

Useful for:

• Initial staging

• Response assessment

• Detection of residual disease

Histopathology

Excisional lymph node biopsy

Preferred diagnostic procedure.

Immunohistochemistry

Used to establish:

• T-cell lineage

• NK-cell origin

• Prognostic markers

Bone marrow assessment

Bone marrow aspirate and trephine biopsy

Recommended for disease staging.

Staging

Aggressive T-cell lymphomas are staged using the Ann Arbor Classification.

Stage I

Single lymph node region or single extranodal site.

Stage II

Two or more lymph node regions on the same side of the diaphragm.

Stage III

Lymph node involvement on both sides of the diaphragm.

Stage IV

Diffuse extranodal involvement including:

• Bone marrow

• Liver

• Central nervous system

Management

Management depends on:

• Histological subtype

• Disease stage

• Performance status

• Organ involvement

Treatment modalities include:

• Chemotherapy

• Radiotherapy

• Supportive care

• Stem cell transplantation in selected patients

Non-pharmacological treatment

Supportive care

Includes:

• Nutritional support

• Infection prevention

• Blood product support when indicated

• Management of tumour lysis syndrome

Radiotherapy

May be used for:

• Localized disease

• Residual disease

• Palliation of symptomatic lesions

Hematopoietic stem cell transplantation

May be considered in:

• High-risk disease

• Relapsed disease

• Selected patients achieving remission

Pharmacological treatment

First-line treatment

CHEOP regimen

The preferred first-line regimen for many aggressive T-cell lymphomas is CHOP combined with etoposide (CHEOP).

CHEOP regimen details

Cyclophosphamide – 750 mg/m² – intravenous infusion over 1 hour – day 1

AND

Doxorubicin – 50 mg/m² – intravenous infusion over 15 minutes – day 1

AND

Vincristine – 1.4 mg/m² (maximum 2 mg) – intravenous infusion over 10 minutes – day 1

AND

Prednisolone – 100 mg – oral – once daily – days 1–5

AND

Etoposide – 100 mg/m² – intravenous infusion – days 1–3

Frequency:

• Every 21 days

Duration:

• 6–8 cycles

Additional therapies for selected cutaneous T-cell lymphomas

Retinoids

May be used in selected patients with cutaneous involvement.

Interferons

May be used as immunomodulatory therapy.

Low-dose methotrexate

May be beneficial in selected cutaneous T-cell lymphoma subtypes.

Second-line therapy for indolent B-cell lymphoma

Although not a treatment for aggressive T-cell lymphoma, the following regimen may be used for relapsed or refractory indolent B-cell lymphoma:

FC regimen

Fludarabine – intravenous – according to protocol

AND

Cyclophosphamide – intravenous – according to protocol

Management according to subtype

Peripheral T-cell lymphoma

• CHEOP chemotherapy

• Consolidation therapy in selected patients

• Consider stem cell transplantation

Anaplastic large cell lymphoma

• CHEOP-based treatment

• Radiotherapy for localized disease where indicated

Angioimmunoblastic T-cell lymphoma

• Systemic chemotherapy

• Supportive management of immune dysregulation

Cutaneous T-cell lymphoma

Localized disease

• Topical corticosteroids

• Radiotherapy

Advanced disease

• Retinoids

• Interferons

• Low-dose methotrexate

• Systemic chemotherapy when indicated

Referral

All patients with suspected or confirmed aggressive T-cell lymphoma should be referred to specialized hematology or oncology centres.

Urgent referral indications

• Rapidly enlarging lymphadenopathy

• Superior vena cava obstruction

• Airway compromise

• CNS involvement

• Severe cytopenias

• Tumour lysis syndrome

• Progressive organ dysfunction

Complications

Disease-related complications

• Bone marrow failure

• Severe infections

• Organ infiltration

• Superior vena cava obstruction

• Tumour lysis syndrome

• Progressive cachexia

Treatment-related complications

Chemotherapy

• Febrile neutropenia

• Myelosuppression

• Mucositis

• Peripheral neuropathy

• Cardiotoxicity

• Secondary malignancies

Radiotherapy

• Skin toxicity

• Fibrosis

• Secondary cancers

Prognosis

Aggressive T-cell lymphomas generally have a poorer prognosis than diffuse large B-cell lymphoma.

Prognosis depends on:

• Histological subtype

• Disease stage

• Performance status

• LDH level

• Bone marrow involvement

• Response to treatment

Early diagnosis and prompt initiation of chemotherapy improve outcomes.

Prevention

Primary prevention

• HIV prevention and treatment

• Early management of chronic viral infections

• Reduction of unnecessary immunosuppression when possible

Secondary prevention

• Early investigation of persistent lymphadenopathy

• Prompt biopsy of suspicious lesions

• Early specialist referral

Tertiary prevention

• Regular follow-up after treatment

• Monitoring for relapse

• Early management of treatment complications