Foundations of Cancer: Biology, Diagnosis, and Patient Care

Cancer is one of the most important topics in modern health care. Understanding how cancer starts, how it spreads, and how it can be prevented or treated helps students, health workers, and patients make informed decisions. This course-style article provides a step-by-step overview of cancer biology, risk factors, screening methods, treatment options, and patient support.

Course Objectives

By the end of this article, the reader should be able to:

• Explain what cancer is and how normal cells become cancerous.
• Describe common risk factors and how lifestyle can influence cancer risk.
• Recognize the main types and stages of cancer.
• Understand the role of screening, early detection, and diagnosis.
• Outline major treatment options and their goals.
• Discuss how to support patients physically, emotionally, and socially.

Lesson 1: What Is Cancer?

Cancer is a group of diseases in which abnormal cells grow and divide in an uncontrolled way. Healthy cells follow an orderly cycle: they grow, divide, perform their function, and die when they are old or damaged. Cancer cells ignore these rules. They keep dividing, form masses called tumors, and can invade or destroy nearby tissues.

Most cancers start with damage to the DNA inside a cell. DNA controls how a cell behaves. When the DNA is damaged and the body cannot repair it, the cell may begin to grow out of control. Over time, more changes accumulate and the cell behaves less and less like a normal cell.

Recommended Video: Introduction to Cancer

Use this video as a visual explanation of Lesson 1 concepts.

Lesson 2: How Normal Cells Turn Into Cancer Cells

The change from a normal cell to a cancer cell is called carcinogenesis. It usually happens slowly over many years. Repeated damage to DNA can affect genes that control cell growth:

• Oncogenes become overactive and push cells to grow and divide too quickly.
• Tumor suppressor genes lose their function and can no longer stop damaged cells from dividing.
• DNA repair genes fail to correct mistakes in the DNA.

When enough of these changes happen, the cell can start to grow without normal control signals, avoid cell death, and create its own blood supply. Eventually, cancer cells can break away from the original tumor and spread through the blood or lymphatic system.

Lesson 3: Causes & Risk Factors of Cancer

Cancer can be caused by a combination of genetic, environmental, and lifestyle factors.

1. Genetic & Family History

• Family history of cancer

• Inherited gene mutations

2. Lifestyle Factors

• Smoking

• Alcohol consumption

• Poor diet & obesity

• Lack of physical activity

• Chronic stress

3. Environmental Exposure

• Radiation

• Chemicals and toxins

• Pollution

4. Infections

• HPV → cervical cancer

• Hepatitis B & C → liver cancer

• H. pylori → stomach cancer

5. Age & Gender

• Risk increases with age

• Some cancers are gender-specific

Lesson 4: Types and Stages of Cancer

Cancers are classified in many ways. One common system is based on the tissue where the cancer begins:

• Carcinomas start in epithelial cells (skin, lining of organs). Examples: breast, lung, colon cancer.
• Sarcomas begin in bone, muscle, or connective tissue.
• Leukemias arise in blood-forming tissues such as the bone marrow.
• Lymphomas start in the lymphatic system.
• Central nervous system cancers begin in the brain or spinal cord.

Staging describes how advanced the cancer is. Most systems consider tumor size (T), spread to lymph nodes (N), and presence of metastasis (M). These are combined into stages 0 to IV, where:

• Stage 0–I: Small, localized cancer.
• Stage II–III: Larger tumors and/or spread to nearby lymph nodes.
• Stage IV: Cancer has spread to distant organs (metastatic disease).

Recommended Video: Cancer Types, Staging, and Treatments

Use this video to reinforce the concepts of classification and staging for Lesson 3.

Lesson 5: Symptoms & Warning Signs

Cancer symptoms can vary, but common warning signs include:

• Unexplained weight loss
• Fatigue & weakness
• Persistent cough or hoarseness
• Unusual bleeding or discharge
• A lump or swelling
• Skin changes or non-healing sores
• Persistent pain
• Change in bowel or bladder habits

 Important:

Early cancer may have NO symptoms — that’s why screening is important.

Lesson 6: Risk Factors and Causes

Cancer has many causes. Some risk factors can be changed, while others cannot. Common examples include:

• Non-modifiable factors: age, sex, family history, inherited genetic mutations.
• Lifestyle factors: tobacco use, alcohol intake, unhealthy diet, physical inactivity, obesity.
• Environmental exposures: radiation, air pollution, workplace chemicals.
• Biological factors: chronic infections (such as HPV, hepatitis B or C, H. pylori) and long-term inflammation.

Having a risk factor does not mean someone will definitely develop cancer, but the chances are higher. Preventive strategies aim to reduce these risks wherever possible.

Lesson 7: Early Detection, Screening, and Diagnosis

Early detection greatly improves the chances of successful treatment. Screening tests look for cancer or pre-cancerous changes in people who do not yet have symptoms. Common examples are mammography for breast cancer, Pap smears for cervical cancer, colonoscopy for colorectal cancer, and low-dose CT scans for some high-risk smokers.

When a screening test or symptom suggests cancer, further diagnostic steps may include imaging (ultrasound, CT, MRI, PET), blood tests, and biopsy. A biopsy is the removal of a small sample of tissue, which is examined under a microscope by a pathologist. Only a biopsy can confirm a cancer diagnosis with certainty.

Recommended Video: Early Detection and Breast Cancer

Place this video within the early detection lesson to show how screening affects outcomes.

Lesson 8: Major Treatment Modalities

Cancer treatment plans are individualized and may include one or more of the following options:

• Surgery: removes the tumor and sometimes surrounding tissue or lymph nodes.
• Radiation therapy: uses high-energy rays to destroy cancer cells or stop them from dividing.
• Chemotherapy: drugs that kill rapidly dividing cells or stop them from dividing.
• Hormone therapy: blocks or slows hormones that fuel certain cancers, such as some breast or prostate cancers.
• Targeted therapy and immunotherapy: newer treatments that attack specific molecules on cancer cells or help the immune system recognize and destroy them.

Treatment may be given with curative intent, to relieve symptoms (palliative care), or to shrink tumors before surgery or radiation (neoadjuvant therapy).

Lesson 9: Side Effects and Supportive Care

Because treatments affect rapidly dividing cells, they can cause side effects such as fatigue, hair loss, nausea, low blood counts, mouth sores, or skin changes. Not every patient experiences the same problems, and there are many ways to reduce or manage side effects.

Supportive care includes pain management, nutritional counseling, physical therapy, and management of emotional or psychological stress. Good symptom control helps patients complete their treatment and maintain the best possible quality of life.

Lesson 10: Living With and Beyond Cancer

Survivorship begins at the moment of diagnosis and continues through treatment and long-term follow-up. Many people live for years after cancer therapy and may need support with:

• Regular follow-up visits and screening for recurrence or new cancers.
• Rehabilitation after surgery, chemotherapy, or radiation.
• Returning to work or school.
• Coping with anxiety, depression, or fear of recurrence.

Care teams often include doctors, nurses, psychologists, social workers, and support groups who work together to help survivors rebuild their lives.

Lesson 11: Communication, Ethics, and Patient Education

Clear communication between health professionals, patients, and families is essential. Patients need honest information about their diagnosis, treatment options, benefits, and risks so they can make informed choices. Cultural beliefs, language barriers, and health literacy should always be considered.

Ethical issues can include informed consent, respecting patient autonomy, confidentiality, and decisions about end-of-life care. Good education and shared decision-making help patients feel respected and involved in their own care.

Lesson 12: Prevention and Public Health Perspectives

Approximately one third of cancers could be prevented through healthy lifestyle choices and public health measures. Key strategies include:

• Not smoking and avoiding secondhand smoke.
• Limiting alcohol intake.
• Maintaining a healthy weight and staying physically active.
• Eating a diet rich in fruits, vegetables, and whole grains, with less processed meat and sugary drinks.
• Protecting skin from excessive sun exposure.
• Receiving recommended vaccines such as HPV and hepatitis B to reduce infection-related cancers.
• Participating in recommended screening programs for early detection.

On a population level, governments and health organizations work to reduce exposure to environmental carcinogens, improve access to screening and treatment, and educate communities about prevention.

Final Summary

Cancer is not a single disease but a complex group of disorders that share the same core problem: abnormal, uncontrolled cell growth. Understanding how cancer develops, what increases the risk, and how it is detected and treated allows health professionals and the public to respond more effectively. Through prevention, early detection, advanced treatment methods, and strong patient support, outcomes continue to improve for many people around the world.