Why is my mouth swelling after radiation and surgery from head & neck cancer?  

The structures inside the mouth are a part of your lymphatic system. The lymphatics are like a highway and located throughout the entire body. Surgery and radiation are used to treat head & neck to cancer and as a result the lymphatics are disrupted. The lymphatic highways are congested. Each part of your cancer treatment plan plays a different role in disrupting your lymphatic system.

Surgery will likely remove lymph nodes from the neck. When this occurs, the lymph fluid that used that lymph node highway is rerouted. Depending how many lymph nodes were needed to be removed by the surgeon depends on how backed up the traffic on that highway becomes.

While participating in a head & neck tumor board and later a cadaver lab at the Cleveland Clinic and discussing lymph nodes with surgeons I learned many things. Lymph nodes appear the easiest to find by your surgeon when they involve cancer. The cancer grabs onto them and the surgeon then works meticulously to cut this out. Depending on where the surgeon is cutting out the cancer they are working around nerves, muscles, and veins. A surgeon’s goal is specific they desire to find the cancer and get it out of your body.

Depending on the methods your cancer center utilizes, the type of cancer you have and the best practice for treatment your team may complete surgery. I use may for a very specific reason. Not all cases of head & neck cancer are treated with surgery. Radiation is a part of many patients’ treatment plan. From tumor board I have learned the radiation oncologist has one specific goal in your plan. Kill the cancer. Their goal is to take the remaining “fields” or areas in your head and neck and clear it of any cancer. While radiation aims to kill all remaining cancer cells it also disrupts your healthy lymphatics in the field of radiation. Therefore, resulting in further clogged highways. When you are driving down a highway and the google map yells at you there is a traffic jam. What do we do? Look for a different highway to get to our end location! That is exactly what your lymphatic system will do. The lymph fluid will attempt to take a different route, however sometimes it needs manual lymph drainage or therapy by a lymphedema therapist to get there.

The swelling inside your mouth is secondary side effect from the treatment to cure the cancer and disrupted lymphatic system.