Lymph nodes throughout the body serve to educate the immune system about pathogens. They do this, in part, by filtering lymphatic fluid. Lymphatic fluid is the tissue fluid that returns to the circulation via the lymphatics, as compared to that part of blood that continues in the veins.
Molecules which have belonged to microbes ( including viruses, bacteria) are transported to the lymph nodes within lymphatic fluid. In addition, tumour cells can penetrate into lymphatic channels and can thus spread to lymph nodes. Upon arriving at lymph nodes, the tumour cells can duplicate and consume the lymph node. When tumour cells spread to a lymph node this is referred to as a nodal metastasis.
Some cancers prefer to spread via the blood stream, eg Follicular thyroid cancer, Renal cell carcinoma. Others tend to spread via lymphatics, eg SCC of the skin or mucous membranes, Papillary thyroid cancer. When the lymph node that is effected by the spread of tumour is in the neck, it usually presents as a painless neck lump.
In a patient with a neck lump, a history of smoking, or of skin cancer treatment is significant. Other medical conditions such a immunosuppression are significant, as is a family history of neck cancer.
Examination involves feeling the neck (palpation) and a systematic examination of the head and neck, often including the use of ultrasound and fibreoptic endoscopy. The skin, the mucosa of the mouth, nose and throat, and an assessment of other lymph nodes of the head and neck are all assessed.
Investigations might also include radiology ( CT, MRI) and will often include taking a biopsy of the lump. Most biopsies are undertaken with a fine needle (FNA) and can be undertaken in the surgery with the use of ultrasound.
The main question patients and the surgeon are interested in answering is, “Is the lump a cancer? “ We understand this and will do all we can to help answer the question and to deal with the outcome as sensitively as possible.
Once a diagnosis of malignancy has been established, the task of finding the source of the primary cancer is undertaken if this has not been established at the initial appointment. Sometimes further scans or investigations are required.
All patients in whom a diagnosis of head and neck malignancy is made should be discussed in a Multidisciplinary Meeting (see page on MDT). The outcome and recommendations of the meeting are then conveyed to the patient, and a plan for management of the cancer is formulated.
For some patients with cancer that has spread to lymph nodes, surgery is required. Others are best treated with radiotherapy and or chemotherapy, with surgery kept for the possibility of the cancer not responding or if the cancer subsequently returns.
Surgery to treat cancer in the lymph nodes is called Neck Dissection. Neck dissection is often combined with surgery to remove the primary cancer. Often after such surgery, either radiation or chemotherapy and radiation are still required to optimally treat the cancer.
A neck dissection is a major operation and aims to remove not just isolated lymph nodes, but rather to remove lymph nodes and lymphatics in designated areas (Levels I-VII) of the neck. The designated areas are determined prior to surgery and will be based on both the known lymph node metastases and the primary cancer. The Levels are indicated on the line drawing above.
Patients who undergo neck dissection will require a general anaesthetic and will also need to stay in hospital for between 3 and 10 days, depending on the extent of the surgery and their rate of recovery.
Complication of neck dissection include bleeding, infection and risks from general anaesthesia. In addition, any of the structures related to the lymph nodes can be harmed by surgery. This can include movement (or motor) nerves ( Accessory nerve to the shoulder, Hypoglossal nerve that moves the tongue, Marginal mandibular nerve which moves the lower lip) and sensory nerves that supply the skin of the neck. Trauma to these nerves can result in them not working properly. The lymphatic vessels can also be traumatised and can cause a leakage of fluid and accumulation following surgery. This will most often settle by itself, but can require further surgery. These complications and the likely effect will be discussed prior to surgery.