Determining if cancer has spread from its original site to the lymph nodes is an important part of cancer staging. Lymph nodes act as filters for the lymphatic system, which carries fluid, nutrients, and waste between the body’s tissues and the bloodstream. Cancer cells can break away from a tumor and travel through the lymphatic system, getting trapped in lymph nodes along the way. When cancer spreads to the lymph nodes, it is known as lymph node metastasis or nodal involvement.
What are the signs of cancer spread to lymph nodes?
There are a few potential signs that cancer may have spread to the lymph nodes:
- Swollen or enlarged lymph nodes – Nodes may become swollen as cancer cells accumulate.
- Firm or hard lymph nodes – Cancerous lymph nodes often feel rubbery or firm.
- Clustered lymph nodes – Cancer may cause multiple nodes in an area to enlarge.
- Change in lymph node shape – Nodes may lose their oval shape and become more rounded.
- Pain or tenderness in lymph nodes – Some may experience discomfort in affected nodes.
However, lymph nodes can also swell due to infection, inflammation, or other benign causes. So swelling alone does not necessarily mean cancer spread. Additional testing is needed to confirm if cancer is present in lymph nodes.
How do doctors test for cancer in lymph nodes?
There are a few methods doctors use to assess lymph nodes when cancer is suspected or diagnosed:
Physical exam
A doctor will closely examine all lymph node areas, feeling for any swelling, tenderness, or changes from normal. Enlarged or abnormal lymph nodes may be an early sign of cancer spread.
Imaging tests
Imaging such as CT, MRI, PET or ultrasound scans can detect enlarged lymph nodes. They may also look for lymph node changes or clusters of nodes that could indicate metastasis.
Biopsy
A lymph node biopsy removes all or part of a node to examine under a microscope. This is the most accurate way to diagnose cancer in lymph nodes. Needle biopsy, incisional biopsy, or excisional biopsy procedures may be done.
Sentinel lymph node biopsy
This procedure identifies and removes the first lymph node that drains the area around a tumor. Cancer typically spreads to sentinel nodes first, so examining this node can indicate whether wider nodal spread has occurred.
What lymph node findings indicate cancer spread?
Doctors look for these lymph node features that may mean cancer has metastasized:
- Size: Lymph nodes over 1 cm or continuing to enlarge are suspicious.
- Consistency: Hard, rubbery nodes that feel abnormal on examination.
- Clustering: Multiple enlarged nodes in the same area.
- Shape: Round nodes that have lost their oval form.
- Central necrosis: Dead tissue in the node’s center seen on biopsy.
- Capsular invasion: Cancer breaking through the node’s outer capsule.
- Positive biopsy: Cancerous cells confirmed in node tissue.
What types of cancer spread to lymph nodes?
Almost all types of cancer have the ability to spread to lymph nodes if not caught early. Cancers known to frequently metastasize to lymph nodes include:
- Breast cancer
- Melanoma
- Head and neck cancers
- Thyroid cancer
- Lung cancer
- Esophageal cancer
- Stomach cancer
- Pancreatic cancer
- Colorectal cancer
- Cervical cancer
- Uterine cancer
- Prostate cancer
- Testicular cancer
- Bladder cancer
- Anal cancer
- Vulvar cancer
- Penile cancer
- Soft tissue sarcomas
- Non-Hodgkin lymphoma
Which lymph nodes are checked for metastatic cancer?
The lymph nodes checked depend on the original cancer location. Some lymph node regions that are frequently assessed include:
Neck (cervical) lymph nodes
Cancers of the head, neck, thyroid, esophagus, and lung often spread here.
Underarm (axillary) lymph nodes
Breast cancer and melanomas may metastasize here.
Groin lymph nodes
Cancers of the legs, genitals, lower abdomen, and anus can spread here.
Chest (mediastinal) lymph nodes
Lung cancer, breast cancer, and other thoracic tumors spread here.
Abdominal (peritoneal) lymph nodes
Spread from stomach, pancreas, colon, ovarian, and other abdominal cancers.
Pelvic lymph nodes
Cervical, uterine, prostate, bladder, and rectal cancers may affect these nodes.
What does lymph node metastasis mean for cancer staging?
Lymph node metastasis is a key factor in cancer staging, which determines treatment options and outlook. In general:
- N0 – No cancer found in lymph nodes.
- N1 – Cancer spread to 1-3 axillary lymph nodes (for breast cancer) or small metastatic nodes near tumor.
- N2 – Cancer in 4-9 axillary lymph nodes (for breast) or larger metastatic node clusters.
- N3 – Cancer in 10+ axillary lymph nodes (for breast) or metastatic nodes on both sides of body.
Higher N stages indicate more advanced cancer that has a worse prognosis. But outcomes still depend on the tumor size, location, and other individual factors.
How is lymph node metastasis treated?
Treatment depends on the cancer type and stage, but may include:
- Surgery – Removal of cancerous lymph nodes.
- Radiation – Targeting affected lymph node areas.
- Chemotherapy – Drug treatments to destroy cancer cells.
- Immunotherapy – Using the immune system to fight cancer.
- Ablation – Destroying tumors with heat, cold, or alcohol injections.
Even if cancer has reached the nearby lymph nodes, treatment can still be effective at controlling it and preventing further spread. Early detection and treatment provide the best outlook.
What is the prognosis when lymph nodes are involved?
The prognosis when cancer has metastasized to lymph nodes depends on:
- Type of cancer
- Number and location of affected nodes
- Size of metastatic nodes
- Extent of nodal involvement
- Presence of treatment side effects
- Patient’s overall health
Those with smaller metastatic nodes, fewer involved nodes, and no cancer in distant organs generally have the most favorable outlooks. Modern treatments can still be very successful at controlling lymph node disease and achieving long-term remission or cure.
Conclusion
Assessing lymph nodes is an important part of cancer staging, as nodal metastasis indicates the disease has started to spread. While lymph node spread sounds ominous, it does not mean cancer cannot be treated. In many cases, lymph node involvement is very treatable, especially when diagnosed early. A biopsy is needed to definitively diagnose cancer in a swollen or abnormal lymph node. With modern therapies, even those with nodal metastasis can still achieve long-term survival and remission.