What is Cancer? Cancer Symptoms, Causes, and Treatment

What is Cancer?

Cancer is a disease caused by cells dividing uncontrollably and spreading to surrounding tissues. The fundamental cause of cancer is changes in the DNA of cells. These changes occur in sections of the genetic structure, namely genes, and are called genetic mutations. These mutations disrupt the normal growth and repair mechanisms of cells, causing them to multiply abnormally and leading to the formation of cancerous tissues.

Cancer is a serious disease that affects millions of people worldwide and can be fatal if not diagnosed early. According to the World Health Organization (WHO), approximately 10 million people die from cancer each year.

What Are the Different Types of Cancer?

Cancer is classified into various categories based on the tissue or cell type in which it develops. Carcinomas are the most common group of cancers, originating in epithelial cells and subdivided into subtypes such as adenocarcinoma and squamous cell carcinoma. Sarcomas develop in connective tissues such as bone, muscle, fat, and cartilage.

Leukemias are cancers that affect the blood and bone marrow and are typically characterized by abnormal blood cell production. Lymphomas originate in the cells of the lymphatic system and are divided into two main types: Hodgkin and non-Hodgkin. Melanomas are a type of skin cancer that originates in melanin-producing cells. Other types of cancer also exist, such as brain and spinal cord tumors, neuroendocrine tumors, and germ cell tumors.

Cancer types are classified according to the tissue or cell type in which they develop as follows:

• Carcinomas,
• Sarcomas,
• Leukemias,
• Lymphomas,
• Melanomas,
• Brain and spinal cord tumors,
• Neuroendocrine tumors,
• Germ cell tumors.

Carcinomas

Carcinomas are the most common type of cancer that develops in epithelial cells. They can affect organs such as the skin, lungs, breast, stomach, and colon. Subtypes include adenocarcinoma (glands), squamous cell carcinoma (flat epithelial cells), and basal cell carcinoma (lower layer of the skin).

Sarcomas

Sarcomas are rare types of cancer that develop in connective tissues (such as bone, muscle, fat, cartilage, and blood vessels). They include subtypes such as osteosarcoma, which develops in bones, and liposarcoma, which develops in fatty tissue, and they typically affect younger age groups.

Leukemias

Leukemias are cancers that originate in the bone marrow and affect the blood and bone marrow. Characterized by abnormal blood cell production, these cancers occur in acute or chronic forms and are commonly seen in childhood cancers.

Lymphomas

Lymphomas are cancers that originate in the cells of the lymphatic system (lymphocytes). They are divided into two main groups: Hodgkin lymphoma, defined by the presence of Reed-Sternberg cells, and non-Hodgkin lymphoma, which represents a broader group of cancers and includes many subtypes.

Melanomlar

Melanomas begin in melanocytes, the cells that produce the pigment melanin, which gives skin its color. This type of cancer, which usually develops in moles or spots on the skin, is one of the most aggressive skin cancers because of its potential to spread quickly.

Brain and Spinal Cord Tumors

These tumors develop in the central nervous system and are categorized into different types, such as gliomas and meningiomas. Brain and spinal cord tumors can be both cancerous (malignant) and noncancerous (benign) and can present with serious neurological symptoms.

Neuroendocrine Tumors

These tumors, which originate in hormone-producing neuroendocrine cells, can develop in different parts of the body. They can range from slow-growing types to aggressive cancers and can cause complex symptoms depending on the hormones they secrete.

Germ Cell Tumors

Germ cell tumors are types of cancer that develop in the testicles or ovaries. However, they can sometimes occur in other parts of the body, particularly the abdomen and chest cavity. They typically affect younger age groups and respond well to treatment.

What are the Types Of Cancer?

The most common types of cancer are lung, leukemia, prostate, lymphoma, breast, colon, and uterine cancer. However, there are many more types of cancer.

Cancer types can be listed as follows:

• Lung cancer
• Leukemia
• Prostate cancer
• Lymphoma
• Breast cancer
• Colon cancer
• Uterine cancer
• Stomach cancer
• Liver cancer
• Kidney cancer
• Thyroid cancer
• Skin cancer
• Eye cancer
• Testicular cancer
• Brain tumors
• Ovarian cancer

Common Types Of Cancer in Women

The most common cancers in women include breast cancer, lung cancer, and colorectal cancer. Common risk factors such as genetic predisposition, hormonal changes, smoking, unhealthy diet, and sedentary lifestyle contribute to the prevalence of these cancers. Additionally, environmental exposures and lifestyle factors increase the incidence of these types of cancer. Early diagnosis is the most critical factor in significantly improving the success of treatment for these cancers.

Common Types of Cancer in Men

The most common cancers in men include prostate cancer, lung cancer, colorectal cancer, and skin cancer (melanoma). Factors such as genetic predisposition, age, smoking, sun exposure, unhealthy lifestyle, and alcohol consumption play a major role in the development of these cancers. Early diagnosis and regular health checkups are also crucial in increasing survival rates for these types of cancer in men.

Common Types of Cancer in Children

The most common cancers in children include leukemia, brain tumors, and lymphomas. Genetic factors, immune system disorders, and environmental influences play a role in the development of childhood cancers. Most childhood cancers originate from rapidly growing and dividing cells. Early diagnosis and modern treatment methods are leading to an increase in survival rates for childhood cancers.

What Are the Stages of Cancer?

Cancer staging is used to determine how advanced the disease is and how far it has spread throughout the body. While staging can vary depending on the type of cancer, it is primarily based on criteria such as tumor size, whether it has spread to lymph nodes, and whether it has metastasized to other organs.

Cancer staging is a process that evaluates how far the cancer has spread in the body and what stage the disease is at. This process includes the location and size of the tumor, whether it has spread to nearby lymph nodes, and whether it has metastasized. Staging is necessary to understand what stage the cancer is at and to select the most appropriate treatment methods for the patient. The staging system may differ for each type of cancer; in some cancers, staging is more clearly defined, while in others, the spread of the disease is assessed based on different criteria.

Early-stage cancer (Stage 1)

Early-stage cancer is the stage where the cancer is confined to the organ in which it originated and has not yet spread. Cancer symptoms are often mild at this stage, and patients may not notice any symptoms. However, regular screenings can detect cancer at this stage.

In cancers diagnosed at an early stage, it may be possible to completely remove the cancerous tissue through surgical intervention. Furthermore, the treatment options applied at this stage significantly reduce the risk of the cancer returning. With early diagnosis, the chances of successful cancer treatment are quite high.

Mid-stage cancer (Stages 2 and 3)

Mid-stage cancer refers to the stages where the cancer has progressed further and is no longer confined to the organ it originated in, but has begun to spread to surrounding tissues and lymph nodes. In stage 2, cancer cells may affect the entire organ and may have spread to areas near the lymph nodes.

In stage 3, the cancer can spread beyond the organ to neighboring tissues and lymph nodes. Treating cancer at these stages becomes more complex, and treatments such as chemotherapy and radiotherapy are used in addition to surgical intervention. During this process, hyperthermic intraperitoneal chemotherapy may also be preferred, especially for intra-abdominal cancers. The treatment process varies depending on the type and spread of the cancer.

Advanced cancer (Stage 4 Cancer)

Advanced cancer is the stage at which cancer has begun to metastasize to other organs. This stage is the most advanced stage of cancer and is usually incurable. However, treatment continues with the aim of slowing the progression of the disease, alleviating symptoms, and improving quality of life.

Methods such as chemotherapy and immunotherapy are often preferred in the treatment of advanced-stage cancer. Treatment for advanced-stage cancer focuses on extending the patient's life and managing symptoms. Metastatic cancers can affect many areas of the body, making treatment more complex.

What Causes Cancer?

Cancer occurs when the mechanism of regular cell division is disrupted, cells undergo mutation, and cells multiply uncontrollably and abnormally. Causes include genetic factors, tobacco and alcohol consumption, exposure to carcinogens, and stress.

This uncontrolled growth in cells can eventually lead to the formation of masses called tumors.

Tumors can be benign or malignant; benign tumors generally remain localized without spreading, while malignant tumors can damage surrounding tissues and metastasize to other parts of the body. One of the fundamental causes of cancer is genetic changes in the DNA of cells. These changes disrupt the normal functioning of cells, causing them to become cancerous.

Common factors that cause cancer include:

• Genetic factors
• Excessive smoking and alcohol consumption
• Unhealthy eating habits (excessively processed foods, low fiber intake),
• Obesity and physical inactivity,
• Excessive exposure to harmful sun rays (UV radiation)
• Environmental toxins and chemicals (e.g., asbestos, benzene),
• Air pollution,
• Certain viral infections (HPV, Hepatitis B or C, Epstein-Barr virus),
• Radiation exposure (medical imaging or nuclear radiation),
• Exposure to radiation (medical imaging or nuclear radiation),

Genetic predisposition is one of the important factors that increase cancer risk. Individuals with a family history of cancer are at greater risk for certain types of cancer. Certain types of cancer, such as breast, ovarian, and colon cancer, can be passed down from generation to generation due to genetic mutations.

Mutations in genes such as BRCA1 and BRCA2 can significantly increase the risk of breast and ovarian cancer. However, genetic factors are not the sole cause of cancer. Most cancer cases arise when environmental factors and lifestyle choices combine.

Environmental factors

Environmental factors also play an important role in the development of cancer. Long-term exposure to factors such as harmful chemicals, cigarette smoke, and air pollution can increase the risk of cancer. For example, contact with toxic substances such as asbestos and radon gas significantly increases the risk of lung cancer.

Occupational exposures are factors that increase the risk of cancer, especially in individuals working with chemicals. Therefore, controlling environmental factors can be effective in reducing cancer risk.

Lifestyle factors

An unhealthy lifestyle is one of the most significant factors increasing the risk of cancer. Excessive alcohol consumption, smoking, obesity, and poor nutrition can trigger cancer development. Smoking is one of the biggest causes of many types of cancer, such as lung, throat, and pancreatic cancer. Obesity is associated with many types of cancer, such as uterine, breast, colon, and kidney cancer. A balanced and healthy diet can significantly reduce the risk of cancer.

Radiation

Exposure to radiation can increase the risk of cancer by damaging the DNA of cells. Individuals who are exposed to the sun's harmful ultraviolet (UV) rays for long periods of time are at high risk of developing skin cancer. Staying outdoors for long periods of time without using sunscreen increases the likelihood of developing skin cancer. Additionally, the risk of certain types of cancer may increase in individuals undergoing radiation therapy.

Infections

Some viruses and bacteria can contribute to the development of cancer. For example, the human papillomavirus (HPV) increases the risk of cervical cancer, while hepatitis B and hepatitis C viruses can cause liver cancer. The bacterium Helicobacter pylori is an infection that increases the risk of stomach cancer. Therefore, preventing these types of infections can be effective in reducing cancer risk.

Hormones and immune system weakness

Certain hormones can trigger the growth of cancer cells. The estrogen hormone, in particular, is one of the main factors that increase the risk of breast cancer. In addition, individuals with weakened immune systems have a reduced ability to fight cancer cells. Diseases that weaken the immune system, such as AIDS, or immunosuppressive treatments can also increase the risk of cancer.

What Are the Symptoms of Cancer?

The most common symptoms of cancer include persistent fatigue, sudden weight loss, loss of appetite, body aches, swollen lymph nodes, slow-healing wounds, unexplained bleeding, bloating and indigestion, and blood in urine or stool. Symptoms may vary depending on the stage and type of the disease.

Common symptoms in cancer patients include:

• Unexplained weight loss
• Chronic fatigue and weakness
• Body aches
• Swelling of the lymph nodes in areas such as the neck, armpits, groin, and breasts
• Changes in bowel and bladder habits (chronic constipation, diarrhea)
• Blood in stool or urine
• Cough
• Wounds that do not heal for a long time
• Abnormal, unexplained bleeding in areas such as the nose or vagina
• Indigestion
• Nausea and vomiting
• Frequent infections and fevers
• Itching of the skin

How is Cancer Diagnosed?

Cancer diagnosis is a multi-step process involving various tests and imaging techniques. Depending on the type of cancer and its location, doctors may use different methods. Early diagnosis increases the treatability of cancer and allows it to be detected before it spreads.

The most commonly used methods in the cancer diagnosis process include imaging techniques, biopsy, and blood tests. Additionally, genetic tests may also play a role in detecting certain types of cancer.

The main cancer diagnostic tests are as follows:

• Physical examination,
• Blood tests (e.g., tumor markers),
• Imaging methods (X-ray, ultrasound, CT, MRI, PET scans),
• Biopsy,
• Endoscopy,
• Genetic tests,
• Cytological examination (e.g., Pap test).

Commonly used imaging techniques include:

• X-ray: It is commonly used to detect bone tumors or certain types of cancer, such as lung cancer. X-rays use low doses of radiation to examine the internal structure of the body.
• Magnetic Resonance Imaging (MRI): MRI uses magnetic fields and radio waves to create detailed cross-sectional images of the body. It is particularly effective in detecting tumors in the brain, spine, and soft tissues.
• Computed Tomography (CT) Scan: CT is an X-ray machine that creates cross-sectional images of the body. It is used to determine the location, spread, and size of cancer.
• Ultrasound: Uses sound waves to visualize internal organs. It is commonly used to detect liver, kidney, and thyroid cancers.
• Positron Emission Tomography (PET-CT): PET scans are used to detect active cancerous tissue because cancer cells consume more energy. When combined with CT, it can also determine whether tumors have spread to other parts of the body.

These imaging methods play an important role in determining whether cancer cells are present and the extent of the cancer's spread. However, a biopsy is usually required for a definitive diagnosis.

Diagnosis with biopsy and blood tests

The most definitive way to diagnose cancer is through a biopsy. A biopsy involves taking a small sample of suspicious tissue for examination in a laboratory. Examination under a microscope reveals whether the cells are cancerous.

There are different biopsy methods available:

• Needle biopsy: A small sample is taken from the suspicious tissue using a needle.
• Surgical biopsy: Part or all of the suspicious tissue is surgically removed and examined.

Biopsy results play a critical role in determining the type and stage of cancer. In addition, certain blood tests can also indicate the presence of cancer. For example, certain proteins called tumor markers, such as CRP, can increase in the blood when cancer cells are present. The PSA (prostate-specific antigen) test is commonly used to diagnose prostate cancer.

Cancer genetic tests

Since some types of cancer may have genetic origins, genetic testing can be used to detect specific mutations or abnormalities. Genetic testing can be an important diagnostic tool, especially for individuals with a family history of cancer. These tests check for the presence of genetic mutations that carry a risk of cancer (such as the BRCA1 and BRCA2 genes). Such genetic mutations can increase the risk of developing certain types of cancer, such as breast and ovarian cancer.

Genetic testing can also guide personalized approaches to cancer treatment. Targeted therapies can be planned based on the patient's genetic makeup and may lead to more effective treatment outcomes.

The importance of early diagnosis in cancer

Early diagnosis and effective treatment play a critical role in stopping the progression of cancer. Although survival rates for many types of cancer have increased thanks to medical research, cancer remains a global health problem today. All cancer-related diseases are addressed by the cancer (oncology) department, which adopts a multidisciplinary approach and is supported by various subspecialties.

How is Cancer Treated?

The main treatment methods for cancer are chemotherapy, radiotherapy, immunotherapy, targeted therapy, stem cell therapy, smart drugs, and palliative care. Cancer treatment options aim to cure or control cancer. The methods used in cancer treatment are generally applied in combination with each other.

The main cancer treatment options are as follows:

• Surgical treatment
• Radiotherapy (radiation therapy)
• Chemotherapy
• Targeted therapy
• Immunotherapy
• Hormone therapy
• Stem cell transplant
• Supportive and palliative care

Surgical intervention

In cancer treatment, the surgical method involves the surgical removal of cancerous tissue. This method is typically used in early-stage cancers, with the goal of completely removing the tumor. The surgeon removes not only the cancerous tissue but also part of the healthy tissue to prevent the spread of cancer. Surgical intervention is particularly successful in localized tumors such as breast cancer, skin cancer, and colon cancer.

Chemotherapy and radiotherapy

Chemotherapy is a treatment method that uses drugs to destroy cancer cells or prevent their growth. As a systemic treatment, it targets cancer cells throughout the body and is often used in combination with other treatment methods. Side effects such as hair loss, nausea, and fatigue are commonly seen during chemotherapy, but these effects can vary from person to person.

Adjuvant therapy

Adjuvant therapy is a supportive treatment administered after primary treatment methods such as surgery. The goal is to eliminate cancer cells that cannot be removed by surgery or that remain behind. Chemotherapy, radiotherapy, or hormone therapy can be used as adjuvant therapy.

Radiation therapy

Radiation therapy, also known as radiotherapy, is a treatment method that uses ionizing radiation to destroy cancer cells or stop their growth in cancer treatment. Commonly referred to as “radiation treatment” among the general public, this method typically plays a significant role in the treatment process for cancer patients. Radiotherapy applications are performed in radiation oncology departments using advanced technology devices that require expertise. This department aims to provide effective treatment by delivering targeted doses of radiation to cancerous tissues while protecting the surrounding healthy tissues.

Immunotherapy and targeted cancer treatment

Immunotherapy is a treatment method that helps the body fight cancer by strengthening the immune system. The immune system recognizes cancer cells and attacks them. Targeted therapies, on the other hand, are performed using drugs specifically designed based on the genetic characteristics of cancer cells. These therapies target specific molecules in cancer cells, providing a more specific effect.

Bone marrow transplant

Bone marrow transplantation is a treatment method used particularly for diseases such as blood cancers. It involves transplanting healthy stem cells to replace bone marrow damaged by high-dose chemotherapy or radiotherapy. This enables the body to produce new, healthy blood cells.

Hormone therapy

Some types of cancer grow in response to hormones. Hormone therapy works by blocking the production of these hormones or by blocking their effects on cancer cells. It is frequently used in the treatment of breast cancer and prostate cancer.

Targeted drug therapy

Targeted drug therapy is a form of treatment that targets the specific genetic characteristics of cancer cells. These drugs aim to stop the spread of the disease by inhibiting the growth and division processes of cancer cells.

Palliative care

Palliative care is not aimed at curing cancer, but rather at alleviating the symptoms caused by cancer and improving the patient's quality of life. It is used to manage pain, shortness of breath, and other distressing symptoms in patients with advanced cancer. Palliative care can be used alongside other treatment methods applied to control cancer.

What should cancer patients avoid eating?

Foods prohibited for cancer patients are those that may negatively affect the treatment process, weaken the immune system, or interact with certain medications. Recommendations are individualized for each patient and must be evaluated under the guidance of a nutritionist or physician.

However, some food and beverage groups that are generally recommended to be avoided are as follows:

• Processed meat
• Fried or burnt food
• Refined sugar
• Alcohol
• Foods that are too salty
• Packaged foods
• Stale and moldy food

Frequently Asked Questions About Cancer

What causes cancer-related itching?

Cancer itching occurs as a result of the body's reaction to harmful substances secreted by cancer cells. Cancers such as liver cancer, bile duct cancer, and Hodgkin's lymphoma can cause itching in the body. Cancer itching manifests itself as persistent itching in a specific area of the body. This itching, which begins without any skin disease in the body, increases especially at night. Cancer-related itching is generally seen together with sweating, weight loss, and fatigue.

Cancer-related itching may occur for the following reasons:

• Paraneoplastic Syndromes: In cancers such as Hodgkin's Lymphoma, the body releases certain substances while fighting cancer, which can cause itching.
• Bile duct obstruction: In people with liver, pancreas, and bile duct cancer, bile salts that accumulate in the blood due to impaired bile flow can cause itching of the skin.
• Skin cancers and skin lesions: Some skin cancers can cause itching. Irritation and swelling may also be seen in the area where the lesions are located.
• Drug-induced itching: During cancer treatment, drugs such as chemotherapy can cause itching as a side effect.

If the itching lasts longer than 2 weeks, is severe enough to affect quality of life, does not respond to medication, and there is no obvious cause for the itching, a doctor should be consulted.

What Are the Differences Between Cancer Cells and Normal Cells?

The process of cancer formation begins with mutations in the DNA of cells. These changes in DNA damage the mechanisms that control the growth and division processes of cells. Normal cells divide when necessary and die when they age. However, cancer cells lose this control and begin to multiply continuously and create cells that do not die.

This abnormal cell growth can cause tumors to develop in various parts of the body. Cancer can affect an organ or body system, disrupting vital functions and leading to death if left untreated.

What is the CRP level in cancer patients?

In scenarios where CRP levels reach 50-100 mg/L and above, cancer may be suspected. However, this value alone is not sufficient for a cancer diagnosis. Detailed tests should be performed.

How is cancer diagnosed?

Signs and symptoms of cancer include extreme fatigue, exhaustion, swollen lymph nodes, slow-healing wounds, nausea, vomiting, headaches, weight loss, persistent coughing, and shortness of breath.

What are the symptoms of a cancerous sebaceous cyst?

Symptoms may include skin discoloration, localized pain, and rapid growth of the mass.

What is the sedimentation rate in cancer?

The normal sedimentation rate is less than 20 mm/hour in women and less than 15 mm/hour in men. In cancer patients, this rate may be 30 mm/hour or higher.

What are the most common types of cancer?

The most common types of cancer are lung cancer, breast cancer, prostate cancer, colon and rectal cancer, skin cancer (melanoma), stomach cancer, liver cancer, and pancreatic cancer.

What are the 10 foods that are good for cancer?

Foods that are good for cancer include broccoli, garlic, turmeric, green tea, pomegranate, tomato, blueberry, spinach, almond, and salmon.

How can the early signs of cancer be recognized?

The first symptoms of cancer are usually fatigue, unexplained weight loss, persistent cough, skin changes, and abnormal lumps.

Which blood test values indicate cancer?

Blood test values monitored for cancer include tumor markers (CA-125, PSA, AFP), high white blood cell count (leukocytosis), low red blood cell count (anemia), high CRP, and high sedimentation rates.

How do we know if we have cancer?

Regular health checkups, screening tests (mammography, colonoscopy), and doctor visits are necessary to determine whether you have cancer. If you have suspicious symptoms (abnormal lumps, chronic fatigue, weight loss), your doctor may diagnose you with a biopsy or imaging tests.

What are the most commonly used methods in cancer treatment?

The most common methods used in cancer treatment are: surgical intervention, chemotherapy, radiotherapy, immunotherapy, hormone therapy, and targeted therapies.

Can cancer spread to the brain?

Yes, some types of cancer can metastasise to the brain. In particular, cancers such as lung, breast, kidney and melanoma can spread to the brain.

How is cancer screening carried out?

Cancer screenings are generally performed according to specific age groups and risk factors. Common screening tests include mammography (breast cancer), colonoscopy (colon cancer), PSA test (prostate cancer) and low-dose CT scan (lung cancer).

Is low white blood cell count cancer?

Blood cancers (leukaemia, lymphoma) can cause a significant drop in white blood cells, but there may be other causes.

Is FDG uptake cancer?

High FDG uptake is usually seen due to the high metabolic activity of cancer cells. However, not all FDG uptake indicates cancer; inflammatory conditions can also produce a similar image.

What is the first sign of cancer?

The first sign of cancer is often persistent fatigue, unexplained weight loss or an abnormal lump felt in the body. The symptom varies depending on the organ where the tumour is located.

What is the most distinctive feature of cancer?

The most distinctive feature of cancer is that cells divide uncontrollably, forming tumours. Over time, this condition tends to spread to surrounding tissues and organs.

Where does cancer spread to first?

Cancer can first spread to the lymph nodes closest to the organ where it originated or, via the bloodstream, to vital organs such as the lungs or liver. The direction and speed of metastasis depend on the type of cancer.

Which cancers do not present symptoms?

Some types of cancer, such as pancreatic, liver and ovarian cancer, may not cause symptoms in the early stages. These cancers are often discovered by chance at an advanced stage.

Which pains could be a sign of cancer?

Persistent pain, pain with no apparent cause, or pain that worsens at night may be a sign of cancer. Bone, back, abdominal and head pain are particularly significant in this regard.

Which cancers cause fatigue?

Leukaemia, lymphoma and certain digestive system cancers can cause intense fatigue. This fatigue does not go away with rest and makes daily life difficult.

What are the 10 signs that cancer is present in the body?

Cancer may present with symptoms such as weight loss, fatigue, skin changes, swelling, coughing, hoarseness, non-healing wounds, difficulty swallowing, digestive problems, and abnormal bleeding. If these symptoms persist for a long time, medical evaluation is required.