Oncology is a branch of medicine that deals with the study, treatment, diagnosis, and prevention of tumors. It encompasses various specialized fields, including medical oncology, radiation oncology, and surgical oncology.
Medical oncologists treat cancer using medication such as chemotherapy, immunotherapy, and targeted therapy. Radiation oncologists treat cancer using radiation therapy, which involves the use of high-energy X-rays or other particles to destroy cancer cells. Surgical oncologists treat cancer using surgery, including removing the tumor and nearby tissue during an operation cancer.net.
Sub-specialties Within Oncology
There are several sub-specialties within oncology, each focusing on specific types of cancers or treatments. Some examples include:
- Neuro-oncology: focuses on cancers of the brain
- Ocular oncology: focuses on cancers of the eye
- Head & Neck oncology: focuses on cancers of the oral cavity, nasal cavity, oropharynx, hypopharynx, and larynx
- Thoracic oncology: focuses on cancers of the lung, mediastinum, esophagus, and pleura
- Gastrointestinal oncology: focuses on cancers of the stomach, colon, rectum, anal canal, liver, gallbladder, pancreas
- Bone & Musculoskeletal oncology: focuses on cancers of the bones and soft tissue
- Dermatological oncology: focuses on the medical and surgical treatment of skin, hair, sweat gland, and nail cancers
- Genitourinary oncology: focuses on cancers of the genital and urinary system
- Pediatric oncology: concerned with the treatment of cancer in children
- Hemato-oncology: focuses on cancers of the blood and stem cell transplantation
- Preventive oncology: focuses on the epidemiology & prevention of cancer
- Geriatric oncology: focuses on cancers in the elderly population
- Pain & Palliative oncology: focuses on the treatment of end-stage cancer to help alleviate pain and suffering
- Molecular oncology: focuses on molecular diagnostic methods in oncology
- Nuclear medicine oncology: focuses on the diagnosis and treatment of cancer with radiopharmaceuticals
- Psycho-oncology: focuses on psychosocial issues in the diagnosis and treatment of cancer patients
- Veterinary oncology: focuses on the treatment of cancer in animals en.wikipedia.org.
Ethical issues in oncology practice can include determining the extent of the disease, prognosis, and entry into clinical trials. These decisions are often influenced by the patient’s personality, religion, culture, and family life. The oncology team should provide sensitive and clear communication to address these complex and emotional issues en.wikipedia.org.
What is Cancer?
Cancer is a disease that occurs when some of the body’s cells grow uncontrollably and spread to other parts of the body [0]. It can start almost anywhere in the human body, which is made up of trillions of cells.
Normally, human cells grow and multiply through a process called cell division to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place.
However, sometimes this orderly process breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t. These cells may form tumors, which are lumps of tissue. Tumors can be cancerous or not cancerous (benign) [0].
How Cancer Spreads
Cancerous tumors spread into or invade nearby tissues and can travel to distant places in the body to form new tumors, a process called metastasis. They may also be called malignant tumors. Many cancers form solid tumors, but cancers of the blood, such as leukaemias, generally do not.
On the other hand, benign tumors do not spread into or invade nearby tissues. When removed, benign tumors usually don’t grow back, whereas cancerous tumors sometimes do. However, benign tumors can sometimes be quite large and cause serious symptoms or be life-threatening, such as benign tumors in the brain [0].
Causes of Cancer
Cancer is caused by certain changes to genes, which are the basic physical units of inheritance. Genes are arranged in long strands of tightly packed DNA called chromosomes. It is a genetic disease, meaning it is caused by changes to genes that control the way our cells function, especially how they grow and divide.
These changes can be inherited from our parents or acquired during our lifetime. Some of these changes can be caused by harmful substances in the environment, such as the chemicals in tobacco smoke and ultraviolet rays from the sun.
The body normally eliminates cells with damaged DNA before they turn cancerous, but the body’s ability to do so goes down as we age, which is part of the reason why there is a higher risk of cancer later in life.
Each person’s cancer has a unique combination of genetic changes, and as the cancer continues to grow, additional changes will occur. Even within the same tumor, different cells may have different genetic changes [0].
How Cancer Starts
Cancer is a large group of diseases that can start in almost any organ or tissue of the body when abnormal cells grow uncontrollably, go beyond their usual boundaries to invade adjoining parts of the body, and/or spread to other organs.
This process is called metastasizing and is a major cause of death from cancer. Cancer is the second leading cause of death globally, accounting for an estimated 9.6 million deaths, or one in six deaths, in 2018.
There are many types of cancer, and they can develop anywhere in the body. The most common types of cancer in men are lung, prostate, colorectal, stomach, and liver cancer, while the most common types in women are breast, colorectal, lung, cervical, and thyroid cancer [1].
Understanding the Different Types of Oncology or Cancer
Cancer is more than just one disease. It is a group of more than 100 different diseases. Cancer can develop anywhere in the body and is named for the part of the body where it started. There are hematologic (blood) cancers, which are cancers of the blood cells, including leukaemia, lymphoma, and multiple myeloma.
There are also solid tumor cancers, which are cancers of any of the other body organs or tissues. The most common solid tumors are breast, prostate, lung, and colorectal cancers. These cancers can be alike in some ways but can be different in how they grow, spread, and respond to treatment.
Some cancers grow and spread quickly, while others grow more slowly. Some are more likely to spread to other parts of the body, while others tend to stay where they started. The treatment for cancer depends on the type and stage of cancer, and often multiple treatments are used to get the best results [2].
Lumps Vs. Cancer
A tumor is a lump or growth of cells. Some lumps are cancerous, but many are not. What makes cancer different is that it can spread to other parts of the body, while benign tumors do not.
Cancer cells can break away from the site where cancer started and travel to other parts of the body through the blood or lymphatic system, causing problems with normal functions in those organs. This ability to invade and spread to other parts of the body is what makes cancer a dangerous and life-threatening disease [2].
Cancer begins when a cell breaks free from the normal restraints on cell division and begins to follow its own agenda for proliferation. All of the cells produced by the division of this first ancestral cell and its progeny also display inappropriate proliferation.
A tumor or mass of cells formed of these abnormal cells may remain within the tissue in which it originated (in situ cancer) or it may begin to invade nearby tissues (invasive cancer). An invasive tumor is said to be malignant, and cells.
Differences between Cancer Cells and Normal Cells
Cancer cells differ from normal cells in several ways. Some of the key differences include:
- Cancer cells grow in the absence of signals telling them to grow, while normal cells only grow when they receive such signals [0].
- Cancer cells ignore signals that normally tell cells to stop dividing or to die (a process known as programmed cell death, or apoptosis) [0].
- Cancer cells invade into nearby areas and spread to other areas of the body, whereas normal cells stop growing when they encounter other cells and do not move around the body [0].
- Cancer cells tell blood vessels to grow toward tumors, supplying them with oxygen and nutrients and removing waste products. Normal cells do not have this ability [0].
- Cancer cells hide from the immune system, which normally eliminates damaged or abnormal cells. They can also trick the immune system into helping them stay alive and grow [0].
- Cancer cells accumulate multiple changes in their chromosomes, such as duplications and deletions of chromosome parts. Some cancer cells have double the normal number of chromosomes [0].
- Cancer cells rely on different kinds of nutrients than normal cells and make energy from nutrients in different way, allowing them to grow more quickly [0].
Some others Differences Include:
Cancer cells also have more genetic changes compared to normal cells, which can affect their growth, division, and differentiation [3]. They don’t stop growing and dividing, resulting in the formation of a tumor, and they don’t specialize or mature properly [4]. Cancer cells can look different under a microscope, with varying sizes and appearances [4].
Cancer cells can grow too rapidly to mature, influencing the behavior of normal cells, molecules, and blood vessels near a tumor [5]. They can also trick the immune system, evading the process that typically gets rid of abnormal or damaged cells [5]. Cancer cells are invasive, starting to invade tissues nearby, and they can spread to other parts of the body [5].
How Does Cancer Develop?
Cancer development, also known as oncogenesis, is a complex process that involves a series of genetic and cellular changes. These changes can occur over a long period of time and are influenced by various factors. The development of cancer typically involves the following steps:
#1. Initiation:
Cancer development begins with a genetic alteration in a normal cell. This alteration, known as a mutation, can be caused by various factors such as exposure to carcinogens (substances that promote cancer development) or errors during DNA replication. Mutations can occur in specific genes called oncogenes or tumor suppressor genes.
Oncogenes promote cell growth and division, while tumor suppressor genes regulate cell growth and prevent the formation of tumors. Mutations in these genes can disrupt the normal control mechanisms that regulate cell growth, leading to uncontrolled cell division.
#2. Promotion:
After the initiation stage, the mutated cell can undergo further changes that promote its survival and growth. These changes can be influenced by various factors, including hormones, inflammation, and exposure to certain chemicals. During this stage, the mutated cell begins to divide more rapidly, forming a small cluster of abnormal cells called a premalignant lesion or dysplasia.
#3. Progression:
In the progression stage, the premalignant lesion develops into a malignant tumor. This involves additional genetic and cellular changes that further enhance the growth and invasive properties of the cancer cells.
The tumor cells acquire the ability to invade nearby tissues and spread to distant sites in the body through a process called metastasis. The progression stage is characterized by the accumulation of more genetic alterations, leading to increased genetic instability and heterogeneity within the tumor.
It is important to note that cancer development is a multistep process, and not all premalignant lesions progress to cancer. The development of cancer is influenced by a combination of genetic, environmental, and lifestyle factors.
Common Risk Factors for Oncology Development
Certain risk factors, such as tobacco use, exposure to radiation or certain chemicals, chronic inflammation, certain infections, and inherited gene mutations, can increase the likelihood of cancer development.
However, it is important to remember that having a risk factor does not guarantee the development of cancer, as many individuals with risk factors never develop the disease. Understanding the process of cancer development has important implications for cancer prevention, early detection, and treatment.
By identifying and targeting the specific genetic and cellular changes that occur during oncogenesis, researchers and clinicians can develop strategies to prevent cancer development, detect it at an early stage when treatment is more effective, and develop targeted therapies that specifically address the underlying molecular abnormalities driving cancer growth.
It is worth noting that the development of cancer is a highly complex and dynamic process that is still the subject of ongoing research. Scientists continue to investigate the underlying mechanisms and factors involved in cancer development to improve our understanding of the disease and develop more effective approaches for cancer prevention and treatment.
Types of Genes that Cause Cancer
There are different types of genes that can cause cancer. These genes play important roles in regulating cell growth, division, and repair. The main types of cancer genes are:
#1. Oncogenes:
Oncogenes are mutated genes that have the potential to cause cells to grow and divide in an uncontrolled manner, leading to the development of cancer. Normally, these genes, known as proto-oncogenes, regulate cell growth and division. However, when proto-oncogenes undergo mutations, they can become oncogenes and promote abnormal cell growth. Oncogenes are often “stuck” in the “on” position, continuously sending signals for cell growth and division, even when not needed [6].
#2. Tumor suppressor genes:
Tumor suppressor genes are responsible for preventing the development of cancer by regulating cell growth, repairing DNA mistakes, and promoting programmed cell death (apoptosis) when necessary. When these genes are functioning properly, they act as a control mechanism to prevent cells from growing and dividing too rapidly or uncontrollably. However, mutations in tumor suppressor genes can lead to their inactivation or loss of function. This can result in uncontrolled cell growth and an increased risk of cancer [6].
#3. DNA repair genes:
DNA repair genes play a crucial role in maintaining the integrity of our DNA by fixing errors and damage that can occur during DNA replication and other cellular processes. Mutations in DNA repair genes can impair their ability to repair DNA damage, including mistakes in other genes. This can lead to the accumulation of additional genetic alterations, including mutations in oncogenes and tumor suppressor genes, increasing the risk of cancer development [6].
Role of the Different Types of Genes in Cancer Development
It is important to note that not all cancers are caused by known gene mutations, and the specific genes involved can vary depending on the type of cancer. Scientists have made significant progress in identifying genetic changes associated with certain types of cancer, but there are still many cancers where the exact gene mutations responsible are not yet known [6].
Understanding the role of these different types of genes in cancer development is crucial for identifying individuals at higher risk of developing cancer, developing targeted therapies, and advancing cancer prevention and treatment strategies. Ongoing research continues to uncover new insights into the genetic basis of cancer and provides opportunities for improving our understanding and management of the disease.
Types of Oncology or Cancer Treatment
When it comes to cancer treatment, there are several types of treatments available, including surgery, chemotherapy, radiation therapy, immunotherapy, targeted therapy, hormone therapy, and more. These treatments can be used individually or in combination, depending on the type and stage of cancer, as well as the goals of treatment [2].
#1. Surgery
Surgery is a common treatment for cancer and involves physically removing the tumor or cancerous tissue from the body. It can be done through open surgery (with a larger incision) or minimally invasive techniques (with smaller incisions). The goal of surgery can vary from total removal of the tumor to partial removal, depending on the situation [7].
#2. Chemotherapy
Chemotherapy is a systemic treatment that uses drugs to kill cancer cells. It can be administered orally or intravenously and travels throughout the body to target and destroy cancer cells. Chemotherapy is often used in combination with other treatments and can be effective in treating different types of cancer [0].
#3. Radiation therapy
Radiation therapy uses high-energy radiation to kill cancer cells and shrink tumors. It can be delivered externally through a machine or internally by placing a radiation source inside or near the cancer. Radiation therapy can be used as a standalone treatment or in combination with surgery or chemotherapy [7].
#4. Immunotherapy
Immunotherapy is a type of cancer treatment that harnesses the power of the immune system to fight cancer cells. It works by stimulating the immune system or by introducing substances that enhance its ability to recognize and attack cancer cells. Immunotherapy can be effective in treating various types of cancer and has shown promising results in recent years [0].
#5. Targeted therapy
Targeted therapy is a treatment that specifically targets the genetic or molecular changes in cancer cells that allow them to grow and divide. It uses drugs or other substances to interfere with specific molecules involved in the growth and spread of cancer. Targeted therapy can be used in combination with other treatments and is often tailored to the individual characteristics of the cancer [7].
#6. Hormone therapy
Hormone therapy is a treatment that slows or stops the growth of hormone-sensitive cancers, such as breast and prostate cancers. It works by blocking the effects of hormones or by lowering hormone levels in the body. Hormone therapy can be administered through medications or by surgically removing hormone-producing organs [0].
Advances in Oncology or Cancer Treatment
In addition to these treatments, there are also newer techniques and approaches being studied and implemented in cancer treatment. These include interventional radiology, which involves minimally invasive techniques using needles and catheters to treat cancer, and photodynamic therapy, which uses a drug activated by light to kill cancer cells [7].
It’s important to note that the specific treatment approach for each individual will depend on various factors, such as the type and stage of cancer, the patient’s overall health, and their preferences. The treatment plan is typically determined by a multidisciplinary team of healthcare professionals, including oncologists, surgeons, radiologists, and other specialists, who work together to provide the most appropriate and effective treatment for each patient’s unique situation [6].
What is the role of an oncologist?
The role of an oncologist is to diagnose, assess, treat, and manage patients with cancer. They are specialized doctors who focus on the study and treatment of cancer. Oncologists can specialize in different areas within oncology, such as medical oncology, surgical oncology, radiation oncology, pediatric oncology, gynecologic oncology, or haematologist-oncology [8].
Medical oncologists
Medical oncologists are responsible for providing treatment and counselling to cancer patients and their families. They design treatment plans, administer systemic therapies such as chemotherapy or immunotherapy, and manage any complications that may arise. They also play a crucial role in clinical research, including clinical trials and translational cancer research [8].
Surgical oncologists
Surgical oncologists are often involved in the initial diagnosis of cancer by performing biopsies. They remove a small section of tissue for examination to check for cancer cells. If cancer is confirmed, surgical oncologists may perform surgeries to remove tumors and surrounding tissues. They also help patients prepare for and recover from surgical procedures during cancer treatment [9].
Haematologist-oncologists
Haematologist-oncologists specialize in treating blood cancers, such as leukaemia and lymphoma. They may also treat blood disorders that are not cancerous, such as sickle cell anaemia and haemophilia. Haematologist-oncologists have completed rigorous training in cancer diagnosis and treatment, including residencies and fellowships [9].
Comprehensive Care to Oncology or Cancer Patients
Oncologists act as the primary healthcare provider for someone with cancer, designing treatment plans, offering supportive care, and coordinating treatment with other specialists. They help patients manage symptoms and side effects of the disease and treatment, and they provide information and recommendations regarding treatment options. Oncologists work as part of a multidisciplinary team, often collaborating with other healthcare professionals to provide comprehensive care to cancer patients [10].
When visiting an oncologist for the first time, it is typically a consultation where the doctor will perform a thorough physical examination, review medical and family history, and request any necessary tests or scans to establish an accurate diagnosis. They will discuss treatment options, assemble a team of specialists as needed, and provide an early prognosis. Oncologists are there to answer any questions patients may have and provide support throughout the treatment process [10].
In summary, the role of an oncologist is to diagnose, treat, and manage cancer patients. They provide treatment options, offer recommendations, help manage symptoms and side effects, coordinate care with other specialists, and play a crucial role in the overall care and well-being of cancer patients.
Choosing a Doctor for Your Cancer Care
When choosing a doctor for your cancer care, there are several factors to consider. It is important to find a doctor who specializes in treating cancer, such as an oncologist. An oncologist is an expert in managing and treating cancer, and they will play a crucial role in your cancer care team [11].
#1. Ask for Recommendations
One way to start your search for a cancer doctor is to ask the doctor who diagnosed you for recommendations. They can provide you with the names of oncologists or other specialists who specialize in treating your specific type of cancer. It is also a good idea to ask for multiple recommendations so that you can choose the doctor you feel most comfortable with [11].
#2. Ask Your Health Insurance Provider
You can also ask your health insurance provider for a list of doctors who treat cancer and are covered by your insurance. This will ensure that you can receive the necessary treatment without incurring excessive out-of-pocket expenses [11].
#3. Get a list of Doctors from the Hospital or Cancer Treatment Facility
Another option is to get a list of doctors from the hospital or cancer treatment facility where you will be receiving treatment. In some cases, you may choose the facility first and then find a doctor who works there. This can be beneficial if you have a preference for a specific treatment center or if you are seeking specialized services available at a particular facility [11].
#4. Seek recommendations from friends or family members
Seeking recommendations from friends or family members who have had experience with cancer can also be helpful. They may be able to provide insights into their personal experiences with doctors and recommend someone they trust [11].
#5. Leverage Online Resources
Online resources can also assist in finding cancer doctors. The American Society of Clinical Oncology (ASCO) has a searchable database of cancer doctors on their website, where you can search by location and specialty. This can help you find doctors who are board-certified and have expertise in treating specific types of cancer [11].
Factors to Consider when Choosing a Cancer Treatment Doctor
When choosing a doctor, it is important to consider factors such as their experience, expertise, communication style, and the level of comfort you feel with them. Cancer treatment is an ongoing process, and you will likely be working with your doctor and cancer care team for an extended period. Feeling comfortable and having a good rapport with your doctor are crucial for effective communication, trust, and collaboration throughout your cancer journey [12].
In summary, when choosing a doctor for your cancer care, consider seeking recommendations from your diagnosing doctor, health insurance provider, hospital or treatment facility, friends or family, and online resources. Take into account factors such as experience, expertise, and personal comfort to ensure that you find a doctor who can provide the best care possible for your specific type of cancer.
Tissue Changes that Are Not Cancer
Tissue changes that are not cancer include hyperplasia, dysplasia, and benign tumors. These changes may have abnormal cell growth or organization, but they are not considered cancerous because they do not invade nearby tissues or spread to other parts of the body like cancer cells do [0].
#1. Hyperplasia
Hyperplasia occurs when cells within a tissue multiply faster than normal, leading to an accumulation of extra cells. However, the cells and tissue still appear normal under a microscope [0]. Hyperplasia can be caused by various factors or conditions, such as chronic irritation [0].
#2. Dysplasia
Dysplasia is a more advanced condition than hyperplasia. It involves a buildup of extra cells that look abnormal under a microscope, and there are changes in how the tissue is organized. The degree of abnormality in the cells and tissue can indicate the likelihood of cancer formation. Some types of dysplasia may require monitoring or treatment, while others may not. An example of dysplasia is an abnormal mole (dysplastic nevus) on the skin, which can potentially develop into melanoma, although most do not [0].
#3. Benign tumors
Benign tumors are noncancerous growths that can occur in various tissues, including breast tissue. They are characterized by abnormal cell growth, but they do not invade nearby tissues or metastasize to other parts of the body. Fibrocystic changes in the breast, for example, are common benign changes that involve fibrous tissue and cysts [2]. Benign breast tumors can be large enough to be detected by hand, and they may present symptoms [9].
Benign Tissue Changes Vs. Cancerous Tumors
It is important to distinguish between benign tissue changes and cancerous tumors, as their behaviors and implications for health and treatment can differ significantly. While benign tumors may not be cancerous, they can still cause symptoms or require medical attention depending on their size and location. Regular monitoring and medical evaluation are often recommended to assess any changes and ensure appropriate management.
Overall, tissue changes that are not cancer can encompass various conditions, including hyperplasia, dysplasia, and benign tumors. These changes may have different levels of abnormality and potential to develop into cancer, but they do not exhibit invasive or metastatic behavior like cancer cells. Proper medical evaluation and monitoring are essential to differentiate between benign tissue changes and cancerous conditions, ensuring appropriate management and care.
CITATIONS
[0] cancer.gov [1] who.int [2] cancer.org [3] technologynetworks.com [4] cancerresearchuk.org [5] cancercenter.com [6] cancer.ca [7] mskcc.org [8] healthcareers.nhs.uk [9] healthline.com [10] webmd.com [11] medlineplus.gov [12] cancer.net
