Lymph Node Cancers are a set of malignancies loosely grouped together because they all involve the lymph nodes. Lymph nodes are only involved in cancers in two cases: when the malignancy begins in the lymph nodes (e.g. lymphomas), or when the cancer spreads through the lymphatics.
What are lymph nodes and what they do?
Lymph nodes are small, rounded and rubbery aggregates of tissue that filter the lymphatic fluid flowing through the body. The filtered fluid rejoins the circulation by entering the veins, thus completing the circuit. Since they are filters, any harmful substances are trapped in them, which is why they are enlarged in infections like tuberculosis. Normal lymph nodes are not palpable. It is only in disease states that they become prominent.
There are two types of lymph cells or lymphocytes: T Lymphocytes or B Lymphocytes. Lymph Node Cancers that arise from these lymphocytes are called Lymphomas.
In a normal body lymphocytes serve a protective function, identifying and engulfing microorganisms, but when they undergo malignant transformation, these lymphocytes grow rapidly and form tumor masses.
Types of Lymph Node Cancer
- Hodgkin’s Lymphoma: occurs due to mutations in B lymphocytes, leading to formation of a characteristic Reed-Steinberg cell, which is diagnostic of Hodgkin’s lymphoma. It can affect any age group, and depending on the subtype, causes enlargement and thickening of lymph node groups starting in the neck and chest, due to fibrous bands encircling the lymphoid tissue. Normal and mutated lymphocytes occur simultaneously in circulation.
- Non Hodgkin’s Lymphoma: includes all the lymphomas that cannot be classified as Hodgkin’s lymphomas. It is generally seen associated with partial or prolonged exposure to the banned chemicals Polychlorinated Biphenyls. Also seen in association with HIV infection.
The other and more major cause of lymph node cancers is metastasis, that is, migration of tumor cells from any existing tumors and malignancies in other parts of the body. This attribute of migration of tumor cells to the lymph nodes is used in staging of cancers through the TNM classification, which is, Tumor-Nodes-Metastasis. Depending on the number and size of lymph nodes involved, N can be 0,1,2,3. Lymph node cancers are most commonly seen associated with Carcinoma breast, prostatic cancer, lung cancer, but also in any cancer that metastasizes through the blood stream or lymphatics.
The Diagnosis and Treatment of Lymph Node Cancer
Diagnosis and confirmation of existing lymph node cancers is done through Excision biopsies, where the node is removed and examined. In the case of multiple enlarged nodes, a Fine Needle Aspiration Cytology can be done, through which the node is aspirated and the fluid/matter examined, to determine what the exact type of lymph node cancer or underlying malignancy there is.
Treatment of Lymph node cancers depends entirely on the type and progression of the cancer. A combined systemic regimen of chemotherapy, radiotherapy and surgery is employed for primary lymph node cancers. In secondary lymph node cancers, the underlying malignancy is the cause of lymph node involvement, and has to be identified and treated as well.