Cancer affects many aspects of our health, including the feet. Several different types of cancer can cause lumps, pain, or changes to the skin in the feet.
Most skin cancers begin as a scaly bump or a mole that changes in size, shape, or color (melanoma). However, they can also spread to other parts of the body, such as your feet.
Bone Cancer
Cancer that starts in bone tissue is rare in the foot, but it can occur. The most common types are osteosarcoma, which develops in cells that create bones, chondrosarcoma, which grows in cartilage, and Ewing sarcoma, which grows in both bone and soft tissue. These cancers usually begin in the pelvis, arms or legs but can also form in the feet and ankles.
Bone cancer is generally classified by how similar the cells look to normal ones, and is divided into stages. Your doctor will tell you whether your tumor is low grade, high grade or advanced. Low-grade cancers grow slowly and are unlikely to spread. High-grade cancers develop quickly and may spread to other parts of the body.
Benign tumors, which do not spread, can form in the bones and nerves of your feet. One of the most common benign tumors is osteochondroma, which develops in the ends of your thigh or shin bones (femur and tibia). This type of tumor is more likely to occur in young people and active adults, and it can be painful. Another benign bone tumor that can be found in the feet is giant cell tumor, which usually appears on the top and sides of your feet near a tendon sheath. This type of tumor is firm to the touch and does not cause pain.
Soft Tissue Sarcoma
Cancers that start in muscle, fat or fibrous tissue (sarcoma) often appear as a lump or swelling in soft tissues. They may not grow or cause symptoms until they get large enough to press on nerves and other parts of the body.
Sarcomas can start in the muscles, tendons and ligaments of the feet. They can also develop in the lining of the blood vessels and lymphatic tissue or in the skin.
The most common type of sarcoma in the foot is basal cell carcinoma, a non-cancerous tumor that usually occurs on the top of the feet. It looks like a small white-colored bump that may be scaly or seeping fluid.
Other types of sarcoma that can develop in the feet include angiosarcoma, which begins in cells that line blood vessels; liposarcoma, which starts in fat cells; and leiomyosarcoma, which forms in smooth muscle tissue. Malignant peripheral nerve sheath tumors (myxofibrosarcomas and neurofibrosarcomas) form in layers of tissue that protect the nerves in your arms, legs and lower back. Rhabdomyosarcoma is a muscle cancer that most often occurs in children and young adults. Some types of sarcoma are caused by genetic syndromes, such as hereditary retinoblastoma, Li-Fraumeni syndrome, familial adenomatous polyposis and tuberous sclerosis.
Skin Cancer
Skin cancer affects all races and sexes, but it’s most common in people who spend lots of time in the sun. It occurs when errors (mutations) in the DNA of skin cells cause them to grow out of control. There are several types of skin cancer that can affect the feet. Basal cell carcinoma, squamous cell carcinoma and malignant melanoma are all possibilities.
Basal cell skin cancer develops on sun-exposed areas of the body and rarely spreads beyond the affected area. It may appear as pearly bumps or patches that ooze, crust or bleed. They may also feel like sores that don’t heal or itch and burn. It’s the least deadly type of skin cancer, but it does cause damage.
Squamous cell skin cancer grows from flat cells that line the outer surface of the epidermis, or top layer of the skin. This type of skin cancer is more common on parts of the body that receive more sunlight, such as the head, neck and arms.
Melanoma is the most serious type of skin cancer. It develops from pigment-producing cells called melanocytes and can spread to other parts of the body through blood vessels if not treated early. It may resemble an existing mole, or it may look like a new spot that changes over time. Periodic self-exams can help identify melanoma at an early stage when it’s easier to treat.
Blood Cancer
The foot is not usually affected by blood cancer. It is more common to have it in other parts of the body, such as the bone marrow or lymphatic system, but occasionally the cancer spreads to the feet from elsewhere in the body.
Blood cancers develop when something goes wrong with the growth and development of your blood cells. This can lead to leukemia, lymphoma or myeloma. Leukemia occurs when immature white blood cells grow too quickly and overrun healthy ones. Lymphoma affects the blood-forming tissue in your bones and lymphatic system, which manages fluid levels in your body. Myeloma is a type of plasma cell cancer that grows in your bone marrow. This crowds out the normal blood-forming cells and reduces your ability to fight infections.
These types of cancer can cause pain and swelling. Some can also make your blood less sticky and increase the risk of bone fractures.
If you are worried that you have a blood cancer, talk to your GP. National guidelines say that if you are referred on the suspected cancer pathway, you should be seen by a specialist within two weeks. This is to help you get the right treatment, quickly. Most people referred don’t have cancer, and catching it early can save lives. If you do have a blood cancer, it may not need immediate treatment and can be monitored instead. This is called being ‘on watch and wait’.