Lymphoma

General Background

Risk Factors

Hodgkin Lymphoma

Pathogenesis

Epidemiology

Clinical Features

  1. Lymphadenopathy - most patients present with painless aymmetrical firm and discrete adenopathy. Nodal size can wax and wane spontaneously. Disease is typically localized initially to a single peripheral LN region and its subsequent progression is by lymphatic spread.
    1. Cervical nodes: 60-70%
    2. Axillary: 10-15%
    3. Inguinal nodes: 6-12%
    4. Retroperitoneal nodes often involved as well (needs CT scan)
  2. Splenomegaly - modest enlargement develops in 50% of patients.
  3. Mediastinal involvement - 10% of patients at presentation. Can be associated with pleural effusions or SVC syndrome.
  4. Cutaneous HL - late complication in 10% of patients.
  5. Prominent constitutional symptoms especially in patients with widespread disease:
    1. Fever (30%) which can be continuous or cyclic (Pel-Ebstein fever)
    2. Pruritus (25%) which can be severe
    3. Alcohol-induced pain
    4. Weight loss, night sweats, weakness, fatigue, anorexia, cachexia.
  6. Hematological and infectious complications

Hematological and biochemical findings

Diagnosis and histological classification

The diagnosis is made by histological examination of an excised lymph node. The distinctive multinucleate polyploid RS cell is central to the diagnosis of the four classic types and nodular lymphocyte-predominant HL which is RS-cell negative.

Clinical Staging

Treatment of HL

Treatment is chemo +/- radiotherapy. The choice will depend on the stage, clinical state A or B (constitutional symptoms), and prognostic factors.

Early-stage disease

Outcomes are excellent. Chemo alone or in combination with radiotherapy. Combined modality treatment (CMT) has no clear long-term OS benefit. - Most patients with chemo alone: ABVD (adriamycin, bleomycin, vinblastina, dacarbazine) x 3 cycles - Most patients with CMT: ABVD x 2 cycles + 20Gy radiotherapy - Unfavourable disease: ABVD x 4-6 cycles + 30Gy radiotherapy for bulky disease

Advanced-stage disease

Cyclical chemotherapy is used for stage III and IV disease. Typically this is 6 cycles AVBD. Highest-risk patients can be treated with BEACOPP (bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine, procarbazine, prednisone).

Relapsed cases

Approx 25% of cases relapse or are refratory to initial therapy. Options include: 1) Alternative combination chemotherapy 2) Brentixumab 3) ASCT 4) Checkpoint inhibitors (PD-L1 or PD-1)

Adjunct Management

Prognosis

Depends on the age, stage, and histology. Overall cure rate is 85%.

Non-Hodgkin Lymphoma

Classification of NHL

Low-grade versus high-grade NHL

Clinical Features of NHL

  1. Superficial lymphadenopathy - asymmetric painless LN in one or more peripheral LN regions.
  2. Constitutional symptoms - fevers, night sweats, weight loss can occur but are less common than in HL, and their presence are associated with disseminated disease.
  3. Oropharyngeal involvement - 5-10% of patients have Waldeyer's ring involvement which can cause obstruction, pharyngitis symptoms
  4. Cytopenias - autoimmune or due to sequestration or diffuse bone marrow disease.
  5. Abdominal disease - hepatosplenomegaly, and often involves retroperitoneal or mesenteric nodes. GI tract is most commonly involved extranodal site after the bone marrow.
  6. Other organs - skin, brain, testis, thyroid involvement.
    1. Skin involvement particularly in Sezary syndrome and mycosis fungoides

Investigations

  1. Histology - excisional whole LN biopsy, or core needle LN biopsy is required. FNA is unreliable due to loss of diasgnostic node architectural features.
  2. Lab investigations:
    1. Cytopenias particularly with leukerythroblastic features, splenomegaly
    2. Lymphoma cells (mantle zone cells, blast cells) in peripheral blood
    3. HIV for all patients
    4. Trephine biopsy of BM
    5. Serum LDH (correlates to proliferation rate and extent of disease, prognostic marker), and serum uric acid
    6. SPEP can show a paraprotein
  3. Cytogenetics - the various subtypes of NHL are associated with characteristic chromosomal translocations which provide diagnostic and prognostic value

Staging NHL

General Treatment of NHL

Initial treatment is generally a combination of chemotherapy + monoclonal anti-tumour antibody. However, various new targeted drugs have been developed: 1) Oral agents against BTK/PI3Kδ proteins - for B-cell CLL 2) Oral agents against ALK - for anaplastic large cell lymphoma 3) Oral agents against BCL-2 - e.g. venetoclax 4) CAR-T therapy is approved for relapsed/refractory patients with some subtypes of lymphoma

Anti-CD20 antibodies in use: 1) Rituximab 2) Ofatumumab 3) Obinutuzumab

Anti-CD30: brentuximab

Specific NHL Subtypes

Low-grade NHL

Small lymphocytic lymphoma

Same morphologic, immunophenotype, and cytogenetics as CLL, with few peripheral blood B cells and no cytopenias from BM involvement. Most patients are elderly and often no treatment is indicated.

Waldernstrom macroglobulinemia (lymphoplasmacytoid lymphoma)

Rare, seen in men > 50. WM is a LPL with production of monoclonal IgM paraprotein. Insidious onset, B symptoms, hyperviscosity syndrome with visual upset. Possible cryoglobulinemia. Can also lead to anemia, bleeding diathesis, neurological involvement, heart failure.

Treatment

Marginal Zone Lymphomas

These are low-grade lymphomas that arise from the marginal zone of B cell germinal follicles. They are classified according to the anatomical site at which they arise: - gastric MALT (H pylori) - Splenic MZL - Nodal MZL

Follicular Lymphoma

About 25% of NHL, median age is 60 years. Associated with t(14; 18) translocation and constitutive BCL-2 expression. Presentation is painless LN.

Mantle Cell Lymphoma

The prognosis is usually poor and overall survival is 4–6 years, although 15% of patients show an indolent course similar to CLL.

High-grade NHL

Diffuse large B-cell Lymphoma (DLBCL)

These are a heterogenous group of disorders representing the classic 'high-grade' lymphomas. They typically present with rapidly progressive lymphadenopathy associated with a fast rate of cellular proliferation. Progressive infiltration may affect bone marrow, GI tract, brain, spinal cord, kidneys, other organs. - What are prognostic factors? Age, performance status, stage, number of extranodal sites, serum LDH, bulky disease > 5 cm, prior history of low-grade disease, AIDS. - What are common treatments? - R-CHOP for 6-8 cycles in 2 or 3-weekly cycles is the mainstay of treatment - Most patients get G-CSF - For patients with localized disease, combined radiotherapy and chemotherapy may be optimal - Prophylactic therapy to prevent CNS disease (intrathecal or high-dose systemic MTX) should be considered for patients with high risk disease, especially with BM involvement - Overall long-term survival is 65%.

Primary mediastinal B cell Lymphoma

Rare NHL that arises in the thymus, presenting mainly in adolescents and young adults. Treatment is R-CHOP or more intensive regimens +/- local radiotherapy or autologous transplant.

Burkitt Lymphoma

Occurs endemically or sporadically. - Endemic (African) BL is seen in areas with chronic malaria exposure and is associated with EBV infection. Associated with MYC oncogene dysregulation. Patients are typically children presenting with massive lymphadenopathy (often of the jaw) which is often very responsive to chemotherapy, although long-term cure is uncommon. - Sporadic BL can occur anywhere in the world, and EBV is seen in 20% of cases. Increased risk in HIV+. Incredibly proliferative. Excellent prognosis with chemotherapy +/- intrathecal chemotherapy.

Primary CNS Lymphoma

Rare tumours, more common in older patients and HIV+ patients. Treatment consists of high-dise MTX with high-dose cytosine arabinoside followed by whole-brain radiotherapy. Associated with long-term cognitive dysfunction.

Lymphoblastic lymphoma

B or T cell, overlap histologically with ALL. Occur in children and young adults.

T-Cell Lymphomas

Once again these comprise about 15% of NHL in Western countries (more in Asia).

Angioimmunoblastic lymphadenopathy

Occurs in patients with lymphadenopathy, HSM, skin rashes, polyclonal increase in serum IgG. Treatment with chemo or histone deacetylase inhibitors.

Mycosis fungoides

This is a chronic cutaneous T-cell lymphoma that presents with severe pruritus and psoriasis-like eczematoid skin lesions that can become plaques and ulcerated tumours. In contrast to Sezary syndrome, there is NO circulating tumour cells. Deeper organs can be affected. Treatment is phototherapy or chemotherapy, and relapsed cases can be treated with histone deacetylase inhibitors.

Sezary syndrome

Dermatitis, generalized erythroderma, lymphadenopathy, circulating T-lymphoma cells.

Adult T-cell leukemia/lymphoma

Associated with HTLV-1 infection.

Enteropathy-associated T-cell lymphomas (EATL)

Associated with gluten-induced enteropathy and have a poor response to treatment.

Anaplastic large cell lymphoma

Common in children. CD30+ and associated with ALK overexpression. Treatment: crizotinib + brentuximab?

Castleman disease

This is a rare LPD that may in some subtypes progress to a B-cell lymphoma. Occurs in localized or multicentric form, most often affecting thoracic or abdominal nodes. Multicentric CD is more associated with HIV+ and systemic symptoms, with HHV-8 coinfection.

References

  1. Lymphoma: Diagnosis and Treatment | AAFP
  2. Non-Hodgkin lymphoma - The Lancet
  3. Diffuse Large B-Cell Lymphoma | NEJM
  4. Non-Hodgkin's lymphoma: A review : Journal of Family Medicine and Primary Care
  5. Hoffbrand Essential Haematology (8th Edition)
  6. Review: Introduction to Lymphoma | SEER Training