Many people going through chemotherapy or radiation notice that their toes or lower legs feel tingly, numb, or burning, as if the skin belonged to someone else. Most often this is described as peripheral neuropathy. Several cancer drugs in particular can irritate or damage the fine nerves in the fingers and toes, so that tingling and numbness begin symmetrically at the toes and fingertips and spread in a glove-and-stocking pattern. When a chemotherapy drug is the cause, this is called chemotherapy-induced peripheral neuropathy (CIPN).
A common question is whether radiation is to blame. Radiation is fundamentally a local treatment that acts mainly on the area being treated. So unless the radiation was aimed at the spine, pelvis, or a region where the leg nerves travel, it is hard to explain distant foot-and-leg tingling by radiation alone. If the numbness appears fairly equally on both sides and worsens in step with the chemotherapy cycle, it makes sense to think of the drugs or other factors before radiation. Unrelated causes such as diabetes, vitamin B12 deficiency, or a lesion pressing on a nerve can also overlap, so the true cause should be sorted out through a medical evaluation.
Some things can help. Noting when the numbness started and how strong it is, then telling your care team, lets you discuss together whether to adjust the dose or type of medication. Because reduced sensation makes burns and cuts easier to miss, check your feet often, wear non-slip shoes, and use good lighting to prevent falls. Gentle walking and stretching within your limits may help. Note that some chemotherapy drugs make the tingling worse on contact with cold, so it is wise to learn which category your medication falls into.
Some signs, on the other hand, deserve a prompt call. If leg strength suddenly drops, walking becomes difficult, the numbness spreads rapidly from day to day, you struggle to control urine or stool, or back pain worsens at the same time, contact your hospital without delay, since these can signal a problem beyond simple neuropathy.
This article is general information to aid understanding and does not replace individual diagnosis or treatment. Because the cause and management of symptoms differ from person to person, please discuss decisions with your own medical team.