In its early stages, lung cancer doesn't typically have symptoms you can see or feel. Later, it often causes coughing, wheezing, and chest pain. But there are other, lesser-known effects that can show up, too - in places you may not expect. (Of course, lung cancer isn't the only thing that can cause these symptoms.)
Some lung tumors make hormone-like chemicals. One of them pushes more blood and fluid to the tissues in your fingertips, so they look thicker or larger than usual. The skin next to your nails may seem shiny, or your nails may curve more than usual when you look at them from the side. It's not common, but finger clubbing is strongly linked to lung cancer: Around 80% of people who have it also have the disease.
One or two of every 10 people with cancer develop high calcium levels, a condition called hypercalcemia. Too much calcium in your blood can give you belly aches and make you queasy or constipated. You may not feel like eating and be really thirsty. Another hormone-like substance that some tumors make will mess with your kidneys, causing cramps and nausea.
In a Danish study, the odds of being diagnosed with small-cell lung cancer were higher for people who had seen a mental health professional for the first time in the past year for illnesses such as anxiety, depression, and dementia. It might be because of how the cancer affects your immune system or hormones, or that it can spread to the brain. High calcium levels related to cancer can also cause confusion, muddled thinking, and depression.
A Pancoast tumor is a type of lung cancer that grows in the upper part of your lung and spreads to your ribs, vertebrae in your spine, nerves, and blood vessels. Because of where these tumors grow, they rarely affect your respiratory system. They're more likely to make your shoulder blade, upper back, and arm hurt instead.
A low red blood cell count, or anemia, is a very common effect of lung cancer. Anemia can make you really tired because your body's tissues aren't getting enough oxygen. And generally speaking, cancer cells like to feed off the nutrients you need to power through a day. So when you have the disease, you may feel like you're dragging.
Small-cell lung cancers may tell your immune system to attack your nervous system, which can in turn affect how your muscles work. It may be hard to stand up when you're sitting, or you might feel unsteady. You could be dizzy from anemia or from a backup in your superior vena cava, the large vein that moves blood from your head to your heart, if it's crowded by a tumor in the upper right lung.
Some people with small-cell lung cancer cell get Cushing's syndrome. The cancer may tell your body to make a hormone called ACTH, which raises the level of cortisol. This leads to fluid retention and weight gain. (You may bruise really easily and feel drowsy, too.)
On the other hand, hypercalcemia and SIADH, a hormone problem that affects your kidneys, tend to make you lose your appetite, so you may start to drop pounds without trying.
Pancoast tumors can also affect the nerves to your eyes and part of your face. This is called Horner syndrome. Symptoms include a small pupil in one of your eyes with a droopy eyelid. You also won't be able to sweat as well on that side of your face.
Small-cell lung cancer that turns your immune system against your nervous system can show up as trouble seeing.
It's rare for lung cancer to be the cause of gynecomastia, but it's possible. Large-cell lung cancer can disrupt your hormone balance and cause tenderness and swelling in male breast tissue.