The signs and symptoms of lung cancer can be elusive. In fact, there’s no proven screening test to detect the disease in its early stages so many patients are only diagnosed once it has advanced and spread elsewhere. As with every cancer, early detection is crucial and treatment is more likely effective in the early stages. Lung cancer isn’t the only health condition that can cause these symptoms, so be sure to talk with your doctor for further assistance.

There are some early and subtle signs that you may be developing lung cancer that can help you get an earlier diagnosis. Surprising lung cancer symptoms can include the following:

1. Fatter fingertips

Certain types of lung tumors can produce hormonal-like changes and one of them pushes blood and fluid to the tissues of the fingertips. This excess blood and fluid makes the fingertips look larger or thicker than usual. Your nails might curve more than usual and the skin next to the nails can look shiny. Around 80% of patients who experience clubbed fingers have lung disease.

2. Mental health issues

According to a Danish study, the risk of being diagnosed with small-cell lung cancer is higher for those who have experienced mental health issues, such as anxiety, depression, and dementia. It could be from the cancer spreading to the brain or how lung cancer affects the immune system or hormones, doctors aren’t yet sure.

3. Back or shoulder pain

Often an overlooked symptom, back or shoulder pain can be a sign of a Pancoast tumor. This type of tumor grows in the upper part of the lung and spreads to the ribs, vertebrae, blood vessels, and nerves. A Pancoast tumor will rarely affect the respiratory system, but it’s more likely to hurt in the shoulder blades, upper back, and arms instead.

4. Gynecomastia

Gynecomastia, or excess breast growth in men, is an early sign of lung cancer. Large-cell lung cancer can disrupt the hormone balance and cause tenderness and swelling in male breast tissue.

5. Anemia and hypercalcemia 

Anemia occurs when the body lacks adequate healthy red blood cells to carry enough oxygen to the body’s tissues and hypercalcemia is when there is a higher than usual level of calcium in the blood. These conditions are both early signs of lung cancer and lead to an irregular or fast heartbeat.

6. Puffy face, neck, or arms

The superior vena cava is responsible for returning deoxygenated blood back to the heart and when it becomes choked by a tumor, the blood from the upper parts of the body has nowhere else to go. The extra fluid will end up in the neck, arms, and face and causing swollen, bluish-red skin on the chest.