Non-Hodgkin’s Lymphoma: An Overview of Introduction, Types, Pathogenesis,Lab Diagnosis, Treatment, Prevention, and Keynotes

Introduction

NHL begins when lymphocytes (B-cells or T-cells) undergo abnormal changes, causing them to multiply uncontrollably and form tumors. These tumors typically start in the lymph nodes but can spread to other organs like the spleen, liver, or bone marrow.

Types of NHLThe

NHL is broadly classified by the type of lymphocyte involved and how quickly it grows.

• By Cell Type:
  • B-cell Lymphomas: Most common (approx. 85-90% of cases). Examples include Diffuse Large B-cell Lymphoma (DLBCL) and Follicular Lymphoma.
  • T-cell Lymphomas: Less common. Examples include Adult T-cell Lymphoma and Mycosis Fungoides.
• By Growth Rate:
  • Indolent (Low-grade): Grow slowly and may not require immediate treatment (e.g., Follicular Lymphoma).
  • Aggressive (High-grade): Grow and spread rapidly, requiring urgent treatment (e.g., DLBCL, Burkitt Lymphoma).

Pathogenesis

The development of NHL involves genetic and environmental triggers:

• Genetic Aberrations: Chromosomal translocations are common, such as t(14;18) in follicular lymphoma, which leads to the overexpression of the BCL-2 gene, preventing programmed cell death (apoptosis).
• Infections: Certain viruses like Epstein-Barr Virus (EBV), HIV, and HTLV-1 can drive malignant transformation.
• Chronic Inflammation: Conditions like H. pylori infection (linked to gastric MALT lymphoma) or autoimmune diseases can cause constant lymphocyte stimulation, increasing the risk of genetic mistakes.

Lab Diagnosis

Diagnosis requires a combination of tissue analysis and systemic staging.

• Biopsy (Gold Standard): An Excision Biopsy (removing a whole lymph node) is preferred over needle biopsies to examine the tissue’s architecture.
• Flow Cytometry & Immunohistochemistry: Used to identify specific surface markers (like CD20) to determine the lymphoma subtype.
• Blood Tests: Often show elevated Lactate Dehydrogenase (LDH), which correlates with disease aggressiveness.
• Imaging: PET-CT scans and MRI are used to determine the stage and location of tumors.

Treatment

Treatment is highly individualized based on the subtype and stage.

• Chemotherapy: The primary treatment, often using multi-agent regimens like R-CHOP.
• Immunotherapy: Monoclonal antibodies like Rituximab target the CD20 marker on B-cells.
• Radiation Therapy: Used for early-stage disease or to relieve localized symptoms.
• Stem Cell Transplant: High-dose chemotherapy followed by a transplant may be used if the lymphoma recurs.
• Watchful Waiting: An option for some slow-growing, indolent lymphomas.

Prevention

There is no definitive way to prevent NHL, but certain risks can be managed:

• Avoiding Known Toxins: Reducing exposure to certain pesticides and chemicals.
• Managing Infections: Early treatment of H. pylori and management of HIV.
• Maintaining Immune Health: Avoiding behaviors that weaken the immune system, as immunosuppression is a major risk factor.

Keynotes

• B-Symptoms: Fever, night sweats, and unexplained weight loss are critical indicators of aggressive disease.
• Dissemination: NHL is often already spread throughout the body by the time it is diagnosed.
• Painless Swelling: The most common sign is a painless, rubbery lump in the neck, armpit, or groin.

Further Readings

1. https://www.ncbi.nlm.nih.gov/books/NBK559328/
2. https://my.clevelandclinic.org/health/diseases/15662-non-hodgkin-lymphoma
3. https://www.ncbi.nlm.nih.gov/books/NBK65899/
4. https://www.msdmanuals.com/professional/oncology/lymphomas/non-hodgkin-lymphomas
5. https://www.learnoncology.ca/modules/non-hodgkins-lymphoma
6. https://www.cancer.org/cancer/types/non-hodgkin-lymphoma/treating.html
7. https://www.cancerresearchuk.org/about-cancer/non-hodgkin-lymphoma/treatment
8. https://www.mayoclinic.org/diseases-conditions/non-hodgkins-lymphoma/diagnosis-treatment/drc-20375685
9. https://www.cancerresearchuk.org/about-cancer/non-hodgkin-lymphoma/treatment/decisions
10. https://www.mdanderson.org/cancer-types/non-hodgkin-lymphoma/non-hodgkin-lymphoma-treatment.html
11. https://emedicine.medscape.com/article/203399-workup
12. https://www.cancerresearchuk.org/about-cancer/non-hodgkin-lymphoma/getting-diagnosed/tests-to-diagnose
13. https://journals.lww.com/jfmpc/fulltext/2020/09040/non_hodgkin_s_lymphoma__a_review.12.aspx
14. https://www.mnoncology.com/cancers-and-blood-disorders/blood-cancers/non-hodgkin-lymphoma/diagnosing-non-hodgkin-lymphoma
15. https://www.mayoclinic.org/diseases-conditions/non-hodgkins-lymphoma/symptoms-causes/syc-20375680