Lung cancer can affect more than just the lungs, and sometimes the most noticeable symptoms have nothing to do with the lungs. It’s important that people with lung cancer know how the condition can affect different parts of the body. That way, they can identify potential complications as soon as possible.

The five-year survival rate for lung cancer is 63 percent when the condition is detected early enough and is limited to the lungs. Unfortunately, only 23 percent of cases are diagnosed at that early stage.

When lung tumors spread to other organs, the five-year survival rate drops to 8 percent. Therefore, learning the signs and symptoms of lung cancer that has spread is an essential component of early detection.

Lung cancer can affect the body in several ways. Following are six symptoms that can result from the condition — or from other causes, including cancer treatments.

1. Fatigue and Low Oxygen Levels

Fatigue is a debilitating feeling of exhaustion. Along with physical pain, fatigue is one of the most commonly reported physical effects of lung cancer. Some of this fatigue may be due to trouble breathing, which can lead to low oxygen levels in the brain.

Notably, fatigue and shortness of breath are both side effects of chemotherapy, the most common form of treatment for lung cancer. Chemotherapy reduces red blood cells, which distribute oxygen throughout the body, providing physical energy. Fewer red blood cells means less oxygen, which in turn means less energy.

Given that lung cancer and chemotherapy both cause fatigue and breathlessness, determining the cause of either symptom can be difficult: Is it the tumor, the treatment — or something else? Smoking, for example, can reduce lung capacity and produce fatigue, obscuring the onset of lung cancer symptoms. Additionally, the emotional toll of living with cancer — including depression — can cause fatigue.

Some specialists recommend keeping a side effects journal to help you better understand the cause of your fatigue — that is, a daily written record of your physical symptoms, such as when you felt fatigued, how long it lasted, and what you may have been doing or eating before the fatigue began creeping in. It’s especially important to notice if your fatigue may be related to trouble breathing and thus low oxygen levels.

Sharing these observations with your doctor can provide a clearer picture of what’s causing the fatigue and how to treat it. If your fatigue is related to oxygen levels, oxygen therapy can help reduce this symptom.

2. Loss of Appetite

Another physical effect of cancers like lung cancer is loss of appetite, which can lead to unhealthy weight loss. “Things improved a little for my husband, but now he feels bad again and has a poor appetite,” one member of MyLungCancerTeam shared.

Approximately half of all people with cancer experience cancer anorexia-cachexia syndrome. “Anorexia” refers to loss of appetite, and “cachexia” refers to malnutrition and physical wasting.

People undergoing chemotherapy or radiation can experience diarrhea, nausea, vomiting, and changes in taste, all of which can contribute to cachexia. The emotional burden of living with a cancer diagnosis can affect eating habits as well.

Loss of appetite and weight can have a marked effect on your quality of life. The symptoms are associated with a higher rate of postsurgical complications and with chemotherapy that’s less effective and has more side effects.

Medications that are used to treat cachexia and stimulate appetite include progestational drugs, cannabinoids, dronabinol, and corticosteroids.

3. Coughing and Other Respiratory Symptoms

“I have been coughing nonstop,” one MyLungCancerTeam member said. Lung cancer can also cause respiratory symptoms, including:

• Coughing up blood
• Chest pain
• Hoarseness
• Persistent cough
• Shortness of breath

Lung cancer can cause fluid to build up in the chest cavity, particularly in the space surrounding the affected lung. Known as pleural effusion, this buildup can cause symptoms such as shortness of breath and chest pain.

People receiving either chemotherapy or radiation treatment for lung cancer should be aware that both treatments involve ionizing radiation, which can cause short- or long-term damage to healthy lung tissue. That, in turn, can also lead to breathing difficulties.

Successfully managing these symptoms is key to improving day-to-day living of people with lung cancer. A combination of pulmonary rehabilitation and social support, tailored to your needs, can be effective.

It’s easy to see that lung cancer would affect lung function and cause respiratory issues. The condition has other lesser-known effects, however, that you may not associate with lung cancer, much less its treatment.

4. Cardiovascular Problems

The heart and blood vessels are part of the circulatory, or cardiovascular, system — the system that pumps blood throughout the body to supply organs with vital nutrients. Cardiotoxicity (damage to the heart muscle) may develop after lung cancer treatment. Some damage may be reversible, but most of it usually is not. However, medications known as cardioprotective agents can help reduce the likelihood of cardiotoxicity in people with lung cancer.

People with lung cancer may experience other cardiovascular conditions, including coronary artery disease, high blood pressure, and irregular heartbeat. Additionally, if your cancer has spread to your lymph nodes, you may need them removed entirely. This can lead to an accumulation of lymphatic fluid, known as lymphedema, which can cause pain and swelling in the extremities — especially the feet and hands.

5. Spread of Cancer to the Bones

When cancer spreads to other parts of the body, it’s called metastasis. Lung cancer is among the types of cancer most likely to cause metastasis to the bone. When bone metastasis occurs, it can cause significant physical pain.

Bone metastasis can cause symptoms such as:

• Weakened bones that fracture more easily
• Weakness in the arms or legs
• Bowel and bladder incontinence
• Hypercalcemia (increased calcium levels in the blood), which can result in constipation, nausea, and vomiting
• Joint pain

6. Headache

Lung cancer can also cause headache, another symptom that may not be initially attributed to the illness. Headache is a common symptom of many conditions, including stress and dehydration. Headaches may also be a sign of more serious conditions, such as lung cancer that’s spreading.

One member described the first symptoms they experienced before learning that their lung cancer had metastasized to the brain: “The only symptoms I had were headaches and zoning out in little bursts here and there, looking back on it.”

Others have discussed headache as a side effect of their chemotherapy regimen. “Headache and constipation have been the side effects of my chemo pills,” one member said.

Talk With Others Who Understand

On MyLungCancerTeam, the social network for people with lung cancer and their loved ones, more than 13,000 people from around the world come together to ask questions, offer support and advice, and connect with others who understand life with lung cancer.

Are you living with lung cancer and worried about its other effects on your body? Do you have any symptoms that you think might be linked to your lung cancer? Share your experiences in a comment below or on your Activities page.