Cancer - Symptoms and Causes

Overview

Cancer is a group of diseases where abnormal cells grow without control and can invade nearby tissues. These cells may also spread to other parts of the body.

Cancer ranks as the second leading cause of death worldwide. The good news is that survival rates for many cancers are getting better.

This improvement comes from advances in three key areas: better screening methods to catch cancer early, more effective treatments, and improved prevention strategies.

Warning Signs

Cancer shows different symptoms based on where it affects the body. While some signs might point to cancer, they can also happen with other conditions.

Common possible warning signs include:

Unusual tiredness
Lumps or thickened areas under the skin
Weight changes without trying
Skin problems like yellowing, redness, non-healing sores, or mole changes
Changes in bathroom habits
Breathing problems or ongoing cough
Trouble swallowing
Voice changes
Stomach discomfort that doesn’t go away
Unexplained pain in muscles or joints
Ongoing fevers or night sweats
Unusual bleeding or bruising

When Medical Help Is Needed

Contact your doctor if you notice any lasting symptoms that worry you. Don’t wait until symptoms become severe or interfere with daily activities.

Even if you feel fine but worry about cancer risks, talk with your healthcare provider.

They can discuss which screening tests might be right for you based on your age, family history, and personal risk factors.

What Causes Cancer

Gene changes tell healthy cells to act in new ways. Cells have special genes that stop them from growing too much. When these genes change, the cells don’t know when to stop multiplying.

Normal body processes include:

Controlled cell growth
DNA repair systems
Cell death when needed

When genes that fix DNA mistakes get damaged, other mistakes don’t get fixed. This can lead to cancer over time.

Sources of Gene Changes

Gene changes happen in two main ways:

Changes you’re born with
- Some gene changes come from your parents
- These make up a small number of cancer cases
- They increase your risk but usually don’t cause cancer by themselves
Changes that happen during life
- Most gene changes happen after birth
- They can come from:
  - Tobacco smoke
  - Too much sun exposure
  - Certain viruses
  - Harmful chemicals
  - Being overweight
  - Hormone imbalances
  - Long-term inflammation
  - Not getting enough physical activity

How Gene Changes Work Together

Cancer usually happens when several gene changes combine. Think of it like this:

Born With Gene Changes	+	Life-Acquired Changes	=	Cancer Risk
Small risk by itself		Environmental factors		Higher risk
Family history		Lifestyle choices		Disease development

For example, if you inherited a gene change that raises your cancer risk, you won’t necessarily get cancer. But you might be more sensitive to things that damage genes, like tobacco smoke.

Scientists believe different types of cancer need different numbers of gene changes to form. Some cancers might develop after just a few changes, while others require many.

Risk Factors

Age Factors

Cancer often develops slowly over many years. This is why people over 65 are diagnosed with cancer more frequently.

However, cancer can affect anyone at any age. The disease is not limited to older adults, though they make up the majority of cases.

Lifestyle Choices

Your daily habits can significantly affect your cancer risk:

Tobacco Use: Smoking is linked to many cancer types.
Alcohol Consumption: More than one drink daily for women or two for men increases risk.
Sun Exposure: Frequent sunburns or excessive UV exposure damages the skin.
Weight: Obesity is connected to several cancer types.
Sexual Practices: Unsafe sex can lead to infections that cause cancer.

Genetic Background

A small percentage of cancers run in families due to specific gene mutations passed from parents to children.

Medical Conditions

Some ongoing health problems can increase cancer risk. For example, people with ulcerative colitis face a higher chance of developing colon cancer.

Surrounding Exposures

Your surroundings may contain substances that increase cancer risk:

Environmental Factors	Potential Risks
Secondhand smoke	Can affect non-smokers in smoking areas
Workplace chemicals	Substances like asbestos and benzene are linked to cancer
Home pollutants	Some household products contain carcinogens

Even if you make healthy personal choices, environmental exposures may still affect your cancer risk.

Health Issues During Cancer

Cancer and its treatments may cause several health problems. Understanding these issues can help patients and caregivers prepare for them.

Pain

Cancer itself or treatments like surgery can cause pain. This pain varies from mild to severe depending on the cancer type and location.

Fatigue

Extreme tiredness is one of the most common cancer complications. It can result from the disease or treatments like chemotherapy and radiation.

This exhaustion feels different from normal tiredness and doesn’t always improve with rest.

Causes of cancer-related fatigue:

The cancer itself
Treatment side effects
Anemia (low red blood cells)
Poor nutrition
Sleep problems
Emotional stress

Breathing Problems

Some patients experience shortness of breath, especially with lung cancer or cancers that spread to the lungs. Tumors may press on airways or lungs, making breathing difficult.

Digestive Issues

Cancer and its treatments frequently affect the digestive system:

Problem	Common Causes	Management Approaches
Nausea/Vomiting	Chemotherapy, radiation to abdomen	Anti-nausea medications, eating smaller meals
Diarrhea	Radiation to pelvis, certain medications	Anti-diarrheal medicines, diet changes
Constipation	Pain medications, reduced activity	Stool softeners, increased fluids, more fiber

Nutritional Challenges

Weight loss affects many cancer patients. The cancer uses the body’s nutrients and can change how the body processes food.

Some patients experience:

Reduced appetite
Changes in taste or smell
Difficulty swallowing
Early feeling of fullness

Body Chemistry Changes

Cancer can disrupt normal chemical balances in the body. This may lead to:

Hypercalcemia (high calcium levels)
Electrolyte imbalances
Hormone disruptions

These changes might cause confusion, excessive thirst, or irregular heartbeats.

Nerve and Brain Effects

Tumors can press on nerves or spread to the brain, causing various problems:

Pain or numbness in specific body parts
Headaches
Seizures
Walking difficulties
Memory or thinking problems

Cancer Spread and Recurrence

Advanced cancer may spread (metastasize) to other body parts. Common sites include bones, liver, lungs, and brain.

Even after successful treatment, some cancers may return months or years later.

Ways to Prevent Cancer

Cancer prevention involves many lifestyle choices that can reduce risk.

Taking these steps may help protect your health:

Stop smoking or never start. Smoking links to many cancer types, not just lung cancer. Quitting now lowers future cancer risk.
Protect yourself from the sun. Limit UV ray exposure by:
- Seeking shade during peak hours
- Wearing protective clothing
- Using sunscreen regularly
Choose healthy foods. Build meals around:
- Fresh fruits and vegetables
- Whole grains
- Lean proteins
- Limited processed meats
Stay active. Exercise for at least 30 minutes on most days. If you’re just starting, begin slowly and gradually increase your activity level.
Keep weight in check.
Maintain a healthy weight through balanced eating and regular physical activity.
Limit alcohol. If you drink, do so in moderation:
- Women: Up to one drink daily
- Men: Up to two drinks daily
Get recommended screenings. Talk with your doctor about which cancer screenings fit your age and risk factors.
Consider vaccinations. Some viruses increase cancer risk. Ask your healthcare provider about vaccines against:
- Hepatitis B (linked to liver cancer)
- HPV (linked to cervical cancer and others)