When cancer spreads, one of the first places it often goes is the lymph nodes. Lymph nodes are small, bean-shaped glands that are part of the body’s immune system. They are located throughout the body and are connected by lymph vessels. Cancer cells can spread from the primary tumor to nearby lymph nodes through these vessels.
If the lymph nodes near a tumor are found to contain cancer, they are called cancerous or metastatic lymph nodes. The presence of cancerous lymph nodes is an important factor when determining the stage and prognosis of a cancer.
Why lymph nodes are checked
Doctors will check the lymph nodes near a tumor to see if the cancer has spread beyond the primary site. This helps determine treatment options and outlook. There are a few different ways lymph nodes may be analyzed:
- Physical exam – The doctor feels the lymph nodes for any swelling, which may indicate cancer.
- Imaging – CT scans, MRIs, PET scans, and ultrasounds can detect enlarged lymph nodes.
- Biopsy – Removing lymph node tissue to check for cancer cells under a microscope.
- Sentinel lymph node biopsy – Removing 1-2 sentinel nodes that drain the tumor area. If they are clear, no further node removal is needed.
When are cancerous lymph nodes removed?
In many cases, cancerous lymph nodes are removed with surgery. This is an important part of cancer treatment for a few reasons:
- Staging – Checking lymph nodes for cancer is critical for proper staging and treatment planning.
- Reduce cancer spread – Removing affected nodes may help reduce the risk of cancer spreading further.
- Improve survival – Node removal is associated with better outcomes for some cancer types.
However, sometimes cancerous nodes may be left in place if:
- The cancer is widespread – Removing nodes will not improve outcomes.
- The patient is too ill for surgery – The risks outweigh potential benefits.
- Radiation is planned – Nodes will be treated with radiation instead.
Types of lymph node removal surgery
There are different operations to remove lymph nodes depending on the cancer site:
| Cancer Type | Lymph Node Removal Procedure |
|---|---|
| Breast cancer | Axillary lymph node dissection |
| Melanoma | Lymph node dissection |
| Gynecologic cancers | Pelvic and para-aortic lymph node dissection |
| Head and neck cancers | Neck dissection |
| Colon cancer | Mesenteric lymph node dissection |
Axillary Lymph Node Dissection
This surgery targets the lymph nodes under the arm on the same side as the breast tumor. It is commonly done for breast cancer patients who have cancerous nodes found by biopsy or sentinel node mapping.
An incision is made in the armpit area, allowing the surgeon to locate, remove, and examine lymph nodes for cancer. Typically between 10-40 nodes are removed.
Neck Dissection
This procedure removes lymph nodes from the neck region. It is done for cancers of the head, neck, thyroid, and salivary glands when lymph node metastasis is suspected or confirmed.
There are different types of neck dissections depending on the extent of node removal:
- Selective neck dissection – Removal of only a few specified lymph node groups.
- Modified radical neck dissection – Removal of most nodes on one side of the neck.
- Radical neck dissection – Removal of nearly all nodes on one side of the neck.
Pelvic and Para-aortic Lymph Node Dissection
This surgery removes lymph nodes from the pelvis and abdomen. It is primarily done for uterine, cervical, ovarian, and bladder cancers.
The pelvic lymph nodes dissected are located along the external iliac, internal iliac, obturator, and common iliac vessels. The para-aortic nodes follow the aorta up from the pelvis into the abdomen.
This extensive nodal removal helps guide treatment and predicts outcomes for advanced gynecologic cancers.
Side effects of lymph node removal
While necessary at times, lymph node removal can come with certain risks and side effects:
- Numbness – Nerve damage may cause numbness in the removal area.
- Lymphedema – Swelling due to a buildup of lymph fluid. More common if radiation is also given.
- Reduced mobility – Shoulder stiffness after axillary node dissection.
- Seroma – Fluid accumulation under the skin.
- Nerve damage – Weakness or paralysis of the diaphragm or shoulders.
- Increased risk of infection – Due to compromised immune function.
Careful surgical technique can help minimize side effects. Patients may need physical therapy after surgery to improve mobility and prevent fluid buildup.
How many lymph nodes are removed?
The number of lymph nodes removed depends on:
- Cancer type and location – Cancers that spread through certain lymph node regions will necessitate more extensive dissection.
- Surgeon’s judgment – More nodes may be removed if there is high risk or evidence of metastasis.
- Patient factors – More nodes may be removed in younger, healthier patients.
Some general guidelines on extent of lymph node removal:
| Procedure | Typical Number of Nodes Removed |
|---|---|
| Lumpectomy + sentinel lymph node biopsy for breast cancer | 1-3 sentinel nodes |
| Modified radical mastectomy with full axillary dissection for breast cancer | 10-40 nodes |
| Selective neck dissection for oral cancer | Around 30 nodes |
| Radical hysterectomy with pelvic lymphadenectomy for cervical cancer | 15+ pelvic nodes |
Removing only a few sentinel nodes when possible can help reduce side effects while still obtaining needed information.
Conclusion
Cancerous lymph nodes are often removed with surgery to stage cancers, reduce recurrence, and improve survival. The type and extent of lymph node dissection depends on the cancer location and spread. While an important part of cancer treatment, removing lymph nodes can lead to risks like lymphedema, nerve damage, and infections. Determining when to remove nodes and how many is a balance between maximizing cancer control and limiting side effects.