Cancer: What is it, Causes, Treatment

What is cancer and what factor is present in all cancers?

Cancer is a term used to describe a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. These cells can invade and destroy surrounding tissues. There are many different types of cancer, each with its own set of causes, symptoms, and treatment options.

One factor present in all cancers is the presence of abnormal cells that grow and divide uncontrollably, forming malignant tumors. These cells can also invade other tissues and organs, leading to the spread of cancer, a process called metastasis.

What are the most common cancers?

The most common types of cancer vary depending on factors such as geographic location, gender, and age. However, some of the most common types of cancer worldwide include:

Breast cancer: Most common in women, but it can also occur in men.
Lung cancer: Often linked to smoking but can also occur in non-smokers.
Colorectal cancer: Affects the colon or rectum and is more common in older adults.
Prostate cancer: Most common in men and often grows slowly.
Skin cancer: Including melanoma and non-melanoma skin cancers, often related to sun exposure.
Bladder cancer: More common in older adults and often linked to smoking.
Stomach cancer: More common in developing countries and often related to infection with H. pylori bacteria.
Liver cancer: Often linked to chronic infection with hepatitis B or C viruses, or cirrhosis.
Cervical cancer: Affects the cervix and is often preventable with regular screening.
Thyroid cancer: Usually has a good prognosis and is more common in women.

These are just a few examples, and there are many other types of cancer that can occur. Each type of cancer has its own risk factors, symptoms, and treatment options.

What is the difference between a normal cell and a cancerous cell?

Normal cells and cancerous cells differ in several key ways:

Growth: Normal cells grow and divide in a controlled manner to replace old or damaged cells. Cancerous cells, on the other hand, grow and divide uncontrollably, forming tumors.
Apoptosis: Normal cells undergo apoptosis (programmed cell death) when they are old or damaged, to prevent the accumulation of abnormal cells. Cancerous cells often evade apoptosis, allowing them to survive and proliferate.
Differentiation: Normal cells mature into specific cell types with specific functions. Cancerous cells often lack this ability to differentiate and may appear more primitive or undifferentiated.
Contact Inhibition: Normal cells stop growing when they come into contact with other cells, a process known as contact inhibition. Cancerous cells often ignore this signal and continue to grow and divide, leading to the formation of tumors.
Metastasis: Normal cells typically remain in the tissue where they belong. Cancerous cells have the ability to invade surrounding tissues and spread to other parts of the body, a process known as metastasis.
Blood Vessel Growth: Cancerous cells can stimulate the growth of new blood vessels (angiogenesis) to supply nutrients and oxygen to tumors, allowing them to grow and spread.

These differences contribute to the ability of cancer cells to proliferate uncontrollably, invade surrounding tissues, and spread to other parts of the body, which are hallmarks of cancer.

How common is cancer?

Cancer is a significant public health concern worldwide. According to the World Health Organization (WHO), there were over 18.1 million new cancer cases and over 9.6 million cancer-related deaths in 2018 alone.

Here are some key statistics on the prevalence of cancer:

Global incidence: Cancer is the second leading cause of death globally, accounting for approximately 17.2% of all deaths.
Prevalence: It is estimated that over 40% of people worldwide will develop cancer at some point in their lives.
Age distribution: Cancer is most common among people aged 65 and older, with the majority of cases occurring in this age group.
Sex distribution: Cancer affects both men and women, with men being more likely to develop cancer than women, especially in older age groups.
Most common types: The most common types of cancer are:
- Breast cancer (28.6% of all cancer cases)
- Lung cancer (12.9% of all cancer cases)
- Prostate cancer (7.3% of all cancer cases)
- Colorectal cancer (6.1% of all cancer cases)
- Stomach cancer (5.6% of all cancer cases)
Incidence rates: The incidence rate of cancer varies greatly across different regions, countries, and populations. For example, in the United States, the overall incidence rate is around 445 per 100,000 people per year.
Survival rates: Survival rates for cancer vary greatly depending on the type and stage of cancer, as well as the availability and effectiveness of treatment options. Overall, the five-year survival rate for all cancers combined is around 67% in the United States.

It’s essential to note that these statistics are based on data from various sources, including the WHO, the International Agency for Research on Cancer (IARC), and national cancer registries.

Remember, while these statistics may seem daunting, advances in cancer research and treatment have led to significant improvements in survival rates and quality of life for people with cancer.

What are common symptoms of cancer?

Cancer symptoms can vary depending on the type and location of the cancer, as well as the individual’s overall health. However, some common symptoms of cancer include:

Unusual or persistent changes in the body:
- Unexplained weight loss or gain
- Changes in appetite or eating habits
- Changes in bowel movements or urination
- Unusual or persistent skin changes, such as moles, freckles, or rashes
Pain or discomfort:
- Chronic or recurring pain in a specific area, such as the back, abdomen, or chest
- Pain that worsens over time
- Discomfort or stiffness in joints or muscles
Abnormal bleeding or discharge:
- Unusual vaginal bleeding or spotting in women
- Blood in stool, urine, or semen
- Discharge or bleeding from an unknown source
Lumps or swelling:
- A lump or swelling in the breast, testicle, or other area
- Unexplained swelling in the neck, groin, or underarm areas
Coughing or difficulty breathing:
- Chronic coughing or wheezing
- Difficulty breathing or shortness of breath
- Chest pain or tightness
Changes in bowel habits:
- Changes in stool frequency, consistency, or color
- Difficulty passing stools
Changes in urinary habits:
- Frequent urination
- Difficulty starting or stopping urine flow
- Blood in urine
Fatigue:
- Feeling unusually tired or weak
Difficulty swallowing:
- Difficulty swallowing food or liquids
Unexplained fevers:
- Recurring fevers without a clear cause

It’s essential to note that these symptoms can be caused by many factors, including non-cancerous conditions. If you’re experiencing any unusual or persistent symptoms, it’s crucial to consult with your healthcare provider to determine the cause and rule out any potential cancer.

Remember, early detection and diagnosis are critical for effective treatment and improving outcomes for cancer patients.

What cancer risks can I control?

While some cancer risks are beyond your control, many are related to lifestyle choices, environmental factors, and genetic predispositions. Here are some cancer risks you can control:

Sun protection:
- Wear sunscreen with at least SPF 30, even on cloudy days
- Seek shade, especially during peak sun hours (10am-4pm)
- Wear protective clothing, including a hat and sunglasses
- Avoid tanning beds and lamps
Smoking and tobacco use:
- Quit smoking or using tobacco products
- Avoid secondhand smoke
- Avoid smoking and tobacco use in your home, car, or workplace
Healthy diet and nutrition:
- Eat a balanced diet rich in fruits, vegetables, whole grains, and lean proteins
- Limit processed and red meat consumption
- Avoid sugary drinks and foods high in added sugars
- Choose low-fat dairy products and healthy fats
Regular exercise and physical activity:
- Aim for at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise per week
- Incorporate strength-training exercises to build muscle mass
- Limit sedentary activities, such as sitting for long periods
Maintain a healthy weight:
- Monitor your body mass index (BMI) and adjust your diet and exercise accordingly
- Aim for a healthy weight range for your height and age
Limit alcohol consumption:
- Drink in moderation (no more than 1-2 drinks per day for women, 2-3 drinks per day for men)
- Avoid binge drinking and drunk driving
Get vaccinated:
- Get vaccinated against HPV, hepatitis B, and other viruses that can increase cancer risk
Avoid exposure to harmful substances:
- Avoid exposure to chemicals like benzene, asbestos, and pesticides in your workplace or environment
- Wear protective gear when working with chemicals or hazardous materials
Practice good hygiene:
- Wash your hands frequently with soap and water
- Practice good oral hygiene by brushing and flossing regularly
Get regular health check-ups:
- Schedule regular health check-ups with your doctor or healthcare provider
- Stay up-to-date on recommended cancer screenings (e.g., mammograms, colonoscopies)
Manage stress:
- Engage in stress-reducing activities like meditation, yoga, or deep breathing exercises
- Practice good sleep habits and aim for 7-9 hours of sleep per night

Remember, controlling cancer risks is an ongoing process that requires commitment to a healthy lifestyle. By making informed choices and adopting healthy habits, you can reduce your risk of developing cancer.

How do doctors diagnose cancer?

Doctors use a combination of physical examination, medical history, laboratory tests, and imaging studies to diagnose cancer. The specific diagnostic approach may vary depending on the type of cancer suspected, the patient’s symptoms, and other factors. Here are some common methods used to diagnose cancer:

Physical Examination: Doctors perform a thorough physical examination to check for abnormalities, such as lumps, swelling, or discoloration.
Medical History: Patients are asked to provide a detailed medical history, including information about their symptoms, past illnesses, and family medical history.
Laboratory Tests: Various laboratory tests can be used to diagnose cancer, including:
- Blood tests: To detect abnormal levels of tumor markers, such as prostate-specific antigen (PSA) or carcinoembryonic antigen (CEA).
- Urine tests: To detect abnormal cells or proteins in the urine.
- Biopsy: A sample of tissue is removed from the body and examined for cancer cells.
Imaging Studies: Imaging studies can help doctors visualize the internal structures of the body and identify any abnormalities. Common imaging studies include:
- X-rays: To detect bone abnormalities or lung tumors.
- Computed Tomography (CT) scans: To detect tumors in various organs and tissues.
- Magnetic Resonance Imaging (MRI) scans: To detect tumors in soft tissues, such as brain or spine.
- Positron Emission Tomography (PET) scans: To detect cancer cells that have spread to other parts of the body.
- Mammography: To detect breast tumors.
Endoscopy: Endoscopy involves inserting a flexible tube with a camera and light on the end into the body to examine the internal organs and tissues.
Biopsy: A biopsy is a procedure where a sample of tissue is removed from the body and examined for cancer cells.
Genetic Testing: Genetic testing can be used to identify genetic mutations that increase the risk of developing certain types of cancer.

Once the diagnosis is made, doctors may use additional tests to determine the stage of the cancer, which is essential for determining treatment options.

What are the four stages of cancer?

Cancer is typically staged using a combination of the following factors:

Tumor size and location: The size and location of the primary tumor (the original tumor) are assessed.
Lymph node involvement: The presence and number of lymph nodes involved in the cancer are evaluated.
Metastasis: The presence of cancer cells in distant parts of the body, such as organs or tissues, is assessed.

The American Joint Committee on Cancer (AJCC) uses a staging system called the TNM system, which categorizes cancer into four stages:

Stage I (Early Stage):

The primary tumor is small (usually less than 2 cm) and confined to a specific area.
Lymph nodes are not involved.
No metastasis is present.

Stage II (Locally Advanced):

The primary tumor is larger (usually between 2-5 cm) but still confined to a specific area.
Lymph nodes may be involved, but the cancer has not spread to other parts of the body.
No metastasis is present.

Stage III (Locally Advanced with Lymph Node Involvement):

The primary tumor is larger (usually greater than 5 cm) and has spread to nearby lymph nodes.
The cancer may have spread to surrounding tissues or organs.
No metastasis is present.

Stage IV (Metastatic):

The cancer has spread to distant parts of the body, such as organs or tissues.
Lymph nodes may be involved, but the primary focus is on the metastasis.
The cancer may have spread to multiple parts of the body.

Keep in mind that not all cancers follow this exact staging system, and some may have additional staging criteria. Additionally, some cancers may be staged using other systems, such as the TNM-modified staging system for breast cancer or the Duke’s staging system for prostate cancer.

How do healthcare providers treat cancer?

Healthcare providers use a multidisciplinary approach to treat cancer, which involves a combination of surgery, radiation therapy, chemotherapy, and targeted therapy. The specific treatment plan depends on the type of cancer, its stage, and the patient’s overall health. Here are some common treatments for cancer:

Surgery: Surgery is often used to remove the primary tumor, as well as any affected lymph nodes or surrounding tissues.
Radiation Therapy: Radiation therapy uses high-energy rays to destroy cancer cells. It can be administered externally or internally, and may be used alone or in combination with other treatments.
Chemotherapy: Chemotherapy uses medications to kill cancer cells or slow their growth. It can be administered orally or intravenously, and may be used alone or in combination with other treatments.
Targeted Therapy: Targeted therapy uses medications that target specific molecules or cells involved in cancer growth and progression. This can be more effective than traditional chemotherapy, as it minimizes harm to healthy cells.
Immunotherapy: Immunotherapy uses medications that stimulate the body’s immune system to fight cancer cells. This can be effective against certain types of cancer, such as melanoma and lung cancer.
Hormone Therapy: Hormone therapy is used to treat cancers that are sensitive to hormones, such as breast cancer and prostate cancer. It involves blocking or removing hormones that feed the cancer cells.
Stem Cell Transplantation: Stem cell transplantation involves replacing the patient’s bone marrow or stem cells with healthy ones from a donor or their own body.
Palliative Care: Palliative care focuses on managing symptoms, improving quality of life, and providing emotional support to patients with advanced cancer.

In addition to these treatments, healthcare providers may also use:

Biological Response Modifiers: Biological response modifiers are medications that stimulate the body’s immune system to fight cancer cells.
Cryotherapy: Cryotherapy uses extreme cold temperatures to destroy cancer cells.
Radiofrequency Ablation: Radiofrequency ablation uses high-energy radio waves to heat and destroy cancer cells.
Liver Directed Therapy: Liver-directed therapy involves delivering medications directly to the liver through catheters or transjugular intrahepatic portosystemic shunts (TIPSS).

It’s essential for patients with cancer to work closely with their healthcare provider to develop a personalized treatment plan that takes into account their unique needs and circumstances.

What are the side effects of cancer treatments?

Cancer treatments can have various side effects, which can vary depending on the type of treatment, the individual’s overall health, and the specific cancer being treated. Some common side effects of cancer treatments include:

Fatigue: Feeling tired or weak is a common side effect of many cancer treatments.
Nausea and vomiting: Chemotherapy and radiation therapy can cause nausea and vomiting, which can be managed with medication.
Hair loss: Chemotherapy and radiation therapy can cause hair loss, which can be temporary or permanent.
Rash or skin changes: Chemotherapy and radiation therapy can cause skin changes, such as rashes, itching, or dryness.
Mouth sores: Chemotherapy and radiation therapy can cause mouth sores, which can be painful and make eating difficult.
Digestive problems: Chemotherapy and radiation therapy can cause digestive problems, such as diarrhea, constipation, or stomach cramps.
Bone marrow suppression: Chemotherapy and radiation therapy can cause bone marrow suppression, which can lead to anemia, low white blood cell count, and low platelet count.
Infection risk: Chemotherapy and radiation therapy can weaken the immune system, making patients more susceptible to infections.
Mental health issues: Cancer treatments can cause anxiety, depression, and other mental health issues.
Sexual dysfunction: Cancer treatments can cause sexual dysfunction, such as decreased libido, impotence, or vaginal dryness.
Infertility: Cancer treatments can cause infertility in both men and women.
Cognitive impairment: Chemotherapy and radiation therapy can cause cognitive impairment, such as memory loss or difficulty concentrating.
Pain: Cancer treatments can cause pain, which can be managed with medication and other therapies.
Bleeding: Chemotherapy and radiation therapy can cause bleeding disorders, such as bleeding gums or easy bruising.
Osteoporosis: Chemotherapy and hormone therapy can cause osteoporosis, which can lead to bone fractures.

It’s essential for patients with cancer to discuss their treatment options and potential side effects with their healthcare provider. With proper management and support, many side effects can be minimized or managed effectively.

When should I see my healthcare provider about a suspected cancer?

If you suspect you have cancer, it’s essential to see your healthcare provider as soon as possible. Here are some situations where you should seek medical attention:

Unusual symptoms: If you’re experiencing unusual symptoms, such as unexplained weight loss, fatigue, or pain that persists or worsens over time, schedule an appointment with your healthcare provider.
Chronic symptoms: If you have chronic symptoms, such as bleeding, coughing, or difficulty swallowing, that don’t improve with treatment or worsen over time, seek medical attention.
Family history of cancer: If you have a family history of cancer, especially if it’s a rare or aggressive type, discuss your concerns with your healthcare provider.
Abnormal screening test: If you receive an abnormal screening test result, such as an abnormal mammogram or colonoscopy, schedule an appointment with your healthcare provider.
Changes in your body: If you notice changes in your body, such as lumps, swelling, or skin changes, that concern you or don’t improve over time, seek medical attention.
Unexplained lumps or masses: If you find a lump or mass in your body that doesn’t go away or doesn’t have a clear explanation, schedule an appointment with your healthcare provider.
Concerns about your health: If you’re concerned about your health or have questions about a specific symptom or condition, don’t hesitate to reach out to your healthcare provider.

When you see your healthcare provider, be prepared to discuss the following:

Your symptoms and medical history
Any changes you’ve noticed in your body
Your family history of cancer
Any previous tests or treatments you’ve received
Any questions or concerns you have about your health

Remember, it’s always better to err on the side of caution when it comes to suspected cancer. Your healthcare provider can assess your symptoms and provide guidance on the next steps to take.