Understanding Cancer: Types, Prevention, and When to See a Doctor

Written by Doctor Chibugo Adinnu

Main Points:

• Cancer is a complex disease characterised by the uncontrolled growth of abnormal cells that can invade and spread to other parts of the body.
• The five major types of cancer are carcinoma, sarcoma, leukaemia, lymphoma, and melanoma, each originating from different types of body tissue.
• Preventative measures such as not smoking, maintaining a healthy diet and weight, and regular physical activity can significantly reduce cancer risk.
• Early detection through screenings and an awareness of one’s body is crucial for effective treatment and better outcomes.
• Cancer is a major global health issue, placing a significant burden on individuals, families, and healthcare systems.

What is Cancer?

Cancer occurs when cells accumulate genetic and epigenetic changes that disrupt normal cell growth, division, and death. These changes let abnormal cells proliferate, evade the immune system, and sometimes invade adjacent tissues and metastasize. Metastasis is responsible for the majority of cancer-related deaths. Understanding how cancer develops helps target prevention, screening and treatment.

As a leading cause of death worldwide, cancer places a tremendous physical, emotional, and financial strain on individuals, families, and communities. Understanding cancer is critical for increasing awareness, promoting early detection, and implementing prevention strategies to reduce its growing global burden.

What are the Types of Cancers

There are more than 200 distinct types of cancer. Clinically, cancers are commonly grouped by cell/tissue of origin. These include:

• Carcinoma: This is the most common type of cancer, originating in the epithelial cells that cover the external and internal surfaces of the body. Examples include breast, lung, prostate, and colon cancers.
• Sarcoma: These cancers develop in the bones, muscles, cartilage, fat, blood vessels, or other soft or connective tissues. Osteosarcoma (bone cancer) and liposarcoma (fat tissue cancer) are examples.
• Leukaemia: Often referred to as “blood cancer,” leukaemia begins in the blood-forming tissue of the bone marrow. It leads to the production of a large number of abnormal white blood cells that don’t function properly.
• Lymphoma: This type of cancer starts in the immune system’s cells, specifically lymphocytes, and affects the lymphatic system. It is divided into Hodgkin lymphoma and non-Hodgkin lymphoma.
• Melanoma: A form of skin cancer, melanoma originates in melanocytes, the cells that produce the pigment (melanin) that gives skin its colour. It is a highly aggressive form of skin cancer.

Key prevention strategies

While it is impossible to guarantee that you will never get cancer, you can significantly reduce your risk by taking proactive steps. 

1. Stop smoking: The single largest preventable cause of cancer and cancer deaths worldwide. Smoking cessation dramatically lowers lung and other cancer risks.
2. Vaccination where indicated: HPV vaccine prevents infections that cause cervical and other cancers; Hepatitis B vaccine prevents chronic HBV infection and reduces liver cancer risk. Discuss vaccination with your clinician.
3. Limit alcohol: Alcohol intake increases risk for several cancers (breast, colorectal, liver, esophageal).
4. Diet & Weight management: Maintain a healthy weight, emphasise fruits, vegetables, legumes, whole grains, and limit processed and high-temperature cooked red meats. Replace some animal proteins with plant-based proteins.
5. Wear Sun protection: Protect skin to reduce melanoma and other skin cancer risk (sunscreen, shade, protective clothing)
6. Reduce exposures to carcinogens: Workplace/household hazards (asbestos, certain chemicals) should be minimised.
7. Know your body & attend recommended screening: Screening finds some cancers early when treatment is more effective. Discuss individual screening schedules with a clinician

Screening For Cancer

Screening recommendations depend on age, sex, risk factors and local guidelines. Examples (general):

• Cervical cancer: HPV-based screening and/or cytology (Pap). HPV vaccination is primary prevention.
• Breast cancer: Many guidelines now support biennial mammography starting around age 40 – 50 depending on authority and individual risk. Discuss with your clinician.
• Colorectal cancer: Stool tests (FIT), colonoscopy at recommended ages based on guidelines and family history.
• Lung cancer: Low-dose CT screening for people at high risk (heavy smokers or recent quitters) following USPSTF criteria. Discuss eligibility with a clinician

Screening recommendations change as evidence evolves; always confirm with local/national guidance and discuss your personal risk with a clinician.

When to see a Doctor

See a clinician if you have persistent, unexplained symptoms such as: unexplained weight loss, blood in stool or urine, persistent lumps, unusual bleeding, a non-healing sore, a persistent cough, or new unexplained pain. You can consult an Oncologist on DoctorOnTap. Early evaluation improves the chance of detecting treatable conditions. If you’re concerned about screening or family history (e.g., multiple relatives with early cancers), book a clinical consultation.

Wrap Up

Cancer remains a formidable health challenge, but knowledge and prevention are our most powerful tools. By understanding what cancer is and its various forms, we can take informed steps to reduce our personal risk of developing cancer. While research continues to advance treatments, a focus on modifiable lifestyle factors, regular screenings for early detection, and vaccination offers the most effective way to combat this disease and improve long-term health outcomes.

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Frequently Asked Questions

Q: Is Cancer contagious?

A: No, cancer is not contagious. You cannot catch it from someone else, nor can it be transmitted through physical contact.

Q: Does stress cause cancer?

A: While stress is known to affect the immune system, there is no definitive scientific evidence to prove that a person’s stress level directly causes cancer.

Q: Does eating sugar “feed” cancer?

A: All cells, including cancer cells, use blood sugar (glucose) for energy. While a high-sugar diet can contribute to weight gain, which is a cancer risk factor, eating sugar does not directly make cancer grow faster. A healthy diet is about balance.

Q: Is cancer an inherited disease?

A: Cancer is a genetic disease caused by changes to genes, but only a small percentage (around 5−10%) of cancers are directly caused by inherited genetic mutations. Most cancers are due to genetic changes that occur during a person’s lifetime.

 

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REFERENCES

1. Types of cancer – Cancer Research UK
2. (PDF) IARC Monographs evaluate consumption of red meat and …
3. What Is Cancer? | Cancer Basics
4. Lung Cancer: Screening | United States Preventive Services Taskforce
5. Reducing Risk for Cervical Cancer