During a robotic prostatectomy, the surgeon may also remove some lymph nodes from the pelvis. This is called a pelvic lymph node dissection. Not every man needs it. Whether it is recommended depends on how likely it is that the cancer has spread to the nodes.
What lymph nodes are
Lymph nodes are small, bean-shaped glands that form part of the immune system. They filter fluid called lymph, which drains from tissues throughout the body. The prostate drains into groups of lymph nodes in the pelvis, along the major blood vessels.
If prostate cancer cells escape from the prostate, the pelvic lymph nodes are one of the first places they may reach.
Why lymph nodes may be removed
Removing lymph nodes has two main purposes:
- Staging: examining the nodes under a microscope shows whether the cancer has spread to them. This is the most accurate way to know.
- Treatment: removing nodes that contain small amounts of cancer may help control the disease in some men.
The results help decide whether further treatment, such as radiotherapy or hormone therapy, is needed after surgery.
Who needs it
The decision is based on the risk of lymph node spread. Surgeons use:
- PSA level
- Gleason score and Grade Group
- MRI findings
- PSMA PET scan results, if done
- risk calculators that combine these factors
Men with low-risk cancer usually do not need lymph node removal, as the chance of spread is very low. Men with intermediate or high-risk cancer are more likely to be offered it. Our guide to robotic surgery for high-risk prostate cancer explains this group in more detail.
Our article on combining MRI and PSMA PET scans explains how imaging helps assess the nodes before surgery.
How it is done
The lymph nodes are removed through the same small incisions as the prostatectomy. The surgeon carefully removes fatty tissue containing the nodes along the blood vessels on each side of the pelvis. It adds some time to the operation.
The extent of the removal varies. A more extended dissection removes more nodes and gives more information but takes longer and may have a slightly higher risk of side effects.
Possible side effects
Most men have no problems, but possible effects include:
- Lymphocele: a collection of lymph fluid in the pelvis. Small ones often cause no symptoms and settle. Larger ones may cause swelling, discomfort or infection and occasionally need draining.
- Leg swelling: called lymphoedema, which is uncommon.
- Blood clots: a small extra risk. Blood-thinning injections are often given after surgery.
- Nerve irritation: rarely, causing numbness or weakness in the thigh.
Report swelling in the legs or lower abdomen, fever or pain to your team.
What the results mean
After surgery, the pathology report will state how many nodes were removed and whether any contained cancer. This is written in the stage as N0, meaning no spread to nodes, or N1, meaning spread. Our guide to TNM staging explains this.
If the nodes are clear, follow-up usually involves PSA tests. If cancer is found in the nodes, your multidisciplinary team may recommend additional treatment.
Recovery
Lymph node removal does not usually add much to the recovery time. Most men still go home after one or two nights. Our guide to recovery after robotic prostate surgery covers the wider recovery.
Questions to ask
- Do you recommend lymph node removal for me, and why?
- How extensive will it be?
- What side effects should I look out for?
NICE guidance on prostate cancer and Prostate Cancer UK both provide further information.
Professor Prokar Dasgupta can explain whether lymph node removal is advised for you at The London Clinic. Please contact the clinic to arrange a consultation.