The physical senses of taste, smell and touch are experienced when signals are sent from sensory cells in the mouth or nose to the brain.
Many types of cancer treatment can interfere with the function of these sensory cells. Some treatments can also damage the nerves responsible for sending signals to the brain.
Chemotherapy – Although the purpose of chemotherapy is to kill or slow the growth of cancer cells, it may also damage some healthy cells, including tastebuds. After chemotherapy, tastebuds begin to grow back quickly and this can confuse the taste processing centre in the brain, causing a change in the taste experience. Some types of chemotherapy can also affect nerve endings, which can change sensitivity to heat and cold.
Radiation therapy – Radiation to the head or neck area can damage the surface of the tongue, mouth, nose or throat, resulting in changes to taste, smell or feeling.
Surgery – Some operations remove the structures needed to experience taste or smell. For example, part of the tongue (including tastebuds), salivary glands, or parts of the nose or nasal passage may be removed or affected by surgery.
Surgery, chemotherapy and radiation therapy can all interfere with normal saliva flow. Saliva helps tastebuds to detect taste. Having a dry mouth over a long period of time can also result in mouth infections or tooth decay, which can cause further problems with taste, smell or feeling.