Oncology: Definition, Importance and All The Different Types of Therapies

It is a branch of medicine that deals with the diagnosis, therapy, cure, and rehabilitation of various forms of cancer.

Including palliative care and rehabilitation of patients affected by cancer.

Oncologists are trained medical professionals who practice and play a critical role in providing medical and psychological support for those affected by adhering to all ethical practices in the cure and prevention of cancer.

There are three types of ‘oncologists’ based on the medical solution: doctors, surgeons, and radiotherapists.

Cancer treatment often involves a combination of therapies:

  • Chemotherapy: prevention of the spread of cancer cells using drugs.
  • Surgery: Removal of the affected part to prevent further spread of cancer.
  • Radiation: elimination of the tumor. Depending on the type of cancer, its stage, the patient’s age, and a variety of other physiological and psychological conditions of the patient.

The uterus or pelvic cancer must be treated with the knowledge of gynecology and oncology, while a pediatric oncologist combines the wisdom of pediatrics and oncology to treat children.

The oncologist plays a vital role throughout the diagnosis, the therapy, and after, even designing the care, treatment, and postoperative rehabilitation.


The Egyptians first described the concept of cancer around 3000 BC.

Later (around 400 BC), the term “carcinoma” was first used by Hippocrates, known as “the father of medicine.”

The Roman physician Celsus (28 BC-50 AD) then translated the word into “cancer,” the Latin meaning “crab.”

At that time, little was understood about the disease, and there was no treatment.

In the eighteenth century, the autopsy practice by Giovanni Morgagni of Padua paved the way for the scientific study of cancer. In the nineteenth century, the use of the microscope by Rudolf Virchow fostered cancer research.

The field of cancer epidemiology also emerged in the eighteenth century, which led to identifying several vital links between exposure to the environment and lifestyle.

Advances in cancer therapy in the late nineteenth and early twentieth centuries included improvements in surgery, radiotherapy, and the first chemotherapy agents (after World War II discovered that nitrogen mustard kills cancer cells ).

Since then, oncology has increased, with refinements in the surgical technique and less invasive procedures; modifications and innovation in radiotherapy, which is associated with lower morbidity; and the development of targeted biological chemotherapy agents.

This vast field constantly covers many organ systems and changes, with new detection patterns, diagnostic tests, and drug discoveries.

Many types of cancer can be treated effectively, and chemotherapy is one of those treatments.

But like other treatments, it often causes side effects. Depending on each person, the side effects of chemotherapy may vary. They rely on the type of cancer, location, medications and dosage, and your general health status.


Why does chemotherapy cause side effects?

Chemotherapy works on dormant cells. Active cells are cells that grow and divide into more of the same type of cell. Cancer cells, like healthy cells, are active cells.

These include cells in your mouth, hair follicles, digestive system, and blood. When chemotherapy damages healthy cells, it is time that side effects occur.

Can side effects be treated?

Yes. The medical staff treating you can help you treat side effects and even help prevent them.

An essential part of cancer treatment is the management of side effects, also known as support or palliative care.

Most treatments involving chemotherapy are much easier to endure than in previous years.

Common side effects

Different drugs cause different side effects. For some types of chemotherapy, the side effects are usually specific. Although, for each person, the experience is different.

Medications called targeted therapies can show how well the treatment is working.

These are some of the most common side effects of chemotherapy:

  • Fatigue: fatigue and fatigue present almost every moment. It is the most common symptom in chemotherapy.
  • Pain: Chemotherapy sometimes causes discomfort. This may include pain from nerve damage (numbness or stinging pains and burning, usually in the fingers and toes), headaches, muscle pain, and stomach pain.

With treatments, most of the pain caused by cancer disappears or improves. However, with each dose, the damage to the nerves often gets worse.

Sometimes, the drug that causes the nerve damage must be stopped when this happens. It takes months or even years for nerve damage caused by chemotherapy to improve or disappear. In some people, it never completely disappears.

The treatment of pain often differs according to what is causing it. If pain occurs during the chemotherapy treatment, it is essential to talk with your doctor.

Although not only chemotherapy can cause pain, it can also be caused by the same cancer.

If chemotherapy is the cause of pain, it can be treated as follows:

  • With medication to relieve pain.
  • Blocking pain signals from the nerves to the brain with spinal treatments or nerve blocks.
  • Adjustment of chemotherapy dose.


Invasive surgery

Surgery is the best treatment to remove the tumor and the surrounding tissue from an operation.

Surgery is the oldest type of cancer therapy and is still an effective treatment for many types of cancer today.

The reasons for surgery vary. However, most of the time, it is used to:

  • To eliminate all or part of cancer or tumor.
  • To diagnose cancer.
  • Discover where cancer is located.
  • Find out if cancer has metastasized to other parts of the body.
  • To restore the appearance or function of the body.
  • To try to improve side effects.

The place where the surgery is performed depends on the amount of recovery time you need and the length of the surgery.

There are many possible places for a surgery depending on the severity of the procedure, such as a surgery center, hospital, and even a doctor’s office.

Outpatient surgery allows the discharge from the center where he has undergone surgery only a few hours after having surgery.

Inpatient surgery means that the patient must stay in the hospital one night or several days after surgery.

Conventional surgery for diagnosis

Generally, a biopsy is a best and only way to diagnose definitive cancer. The biopsy is done through a small incision or cuts in the skin. Then, the surgeon removes part or all of the suspect tissue.

The two types of most recognized and necessary surgical biopsies are:

  • Incisional biopsy: where a part of the area suspected of having cancer is removed, to be evaluated later.
  • Excisional biopsy: This type of biopsy completely removes the area where cancer is suspected, such as a lump in the breast or an unusual mole.

The procedure following the biopsy is examining the tissue removed by observation under a microscope by a pathologist.

The pathologist provides a pathology report to the surgeon or oncologist, who makes the diagnosis.


Staging surgery is done to know the size of the tumor and if it has spread or where it has spread.

Several lymph nodes near the cancer are usually removed during surgery to verify that cancer has not metastasized.

To guide cancer treatment options, your doctor will use the results of this surgery and some other tests.

This surgery can also help predict the possibility of recovery of a patient.

Healing or primary surgery.

Curative surgery is used to remove the tumor and healthy tissue around it. The tissue that surrounds the cancer is called the margin.

The surgeon makes large incisions through the skin, muscles, and bones with conventional surgery.

Professionals use some less invasive surgeries to reduce postoperative pain and accelerate recovery.


When a surgeon can not altogether remove a tumor or remove it can cause considerable damage to the body, debulking surgery is used to remove as much tumor as possible, avoiding causing so much damage to the body.

Chemotherapy and radiation therapy are other treatments available to reduce remaining cancer.

To help reduce the size of a tumor before surgery, some of the treatments above can be implemented.


Palliative treatment helps to improve side effects caused by cancer or a tumor, and palliative surgery has this exact purpose.

For example, surgery can be used to relieve pain or restore physical function when a tumor causes the following complications:

  • Blockage of the intestine or intestines.
  • Obstruction or pressure in other areas of the body.
  • Pressure on a nerve or spinal cord.
  • Bleeding: Certain cancers are more likely to cause bleeding, such as; cancer of the uterus, esophagus, stomach, and intestine.

Minimally invasive surgery

Conventional surgery often requires large incisions. However, only one or several small incisions are made in minimally invasive surgeries.

These surgeries usually result in shorter recovery times and less pain afterward.

Laparoscopic surgery

The doctor will make small incisions in this surgery using a thin, lighted tube with a camera.

The term laparoscopy refers to a minimally invasive surgery of the abdomen.

Laparoscopic surgery can also be done with robotic assistance for some surgeries.

This surgical procedure can be used to treat a woman’s prostate, uterus, ovaries, kidneys, etc.

Laser surgery

The doctor uses a narrow, high-intensity light beam to remove the cancerous tissue.


In cryosurgery, liquid nitrogen is used to kill and freeze foreign cells.

Mohs micrographic surgery

She also called microscopically controlled surgery.

The dermatologist removes the skin cancer, one layer at a time, until all cells in a layer appear to be normal cells when viewed under a microscope.


In this procedure, a flexible thin tube with a light and a camera is inserted into the body.

It can be used in the vagina, rectum, or mouth to examine the organs inside the body.

During the endoscopy process, samples of abnormal tissue can be removed for evaluation.


Radiation therapy uses high-energy radiation to kill cancer cells and reduce tumors.

Radiation therapy expels charged particles, gamma rays, and X-rays to treat cancer.

Radiation can be used in 2 ways, externally with a machine or internally by inserting radioactive material into the body.

Almost all cancer patients receive radiation treatment during some time of their treatment.

How radiation therapy kills cancer cells?

It kills cancer cells when it damages their DNA. Cancer cells whose DNA is damaged beyond repair stop dividing or die.

However, radiation therapy can also damage normal cells and produce side effects.

Doctors consider the potential damage to normal cells when planning a radiation therapy cycle.

The amount of radiation that normal tissue can safely receive is known for all body parts.

Doctors use this information to help them decide where to point radiation during treatment.

Why do patients receive radiation therapy?

Radiation therapy has its primary function in treating cancer, either to prevent the recurrence of the tumor or to eliminate a tumor.

Radiation therapy is also used as a palliative treatment to improve side effects or relieve symptoms and ailments caused by cancer.

Some examples of palliative radiotherapy are:

  • Radiation administered to the brain: to reduce tumors formed by cancer cells that have spread to the brain from another part of the body (metastasis).
  • Radiation is administered to reduce the size of a tumor: that presses the spine or grows inside a bone, which can cause pain.
  • Radiation is administered to reduce the size of a tumor near the esophagus: which can interfere with the patient’s ability to eat and drink.

How is radiation therapy planned for an individual patient?

A radiation oncologist is in charge of developing the plan for the patient’s treatment, which is always started with a simulation.

During the simulation, detailed image scans show the location of a patient’s tumor and the typical areas around it.

These scans are usually done by computed tomography (CT) but may also include magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasound.

CT scans are often used in treatment planning for radiation therapy.

During the simulation and daily treatments, it is necessary to ensure that the patient is in precisely the same position every day as the machine administering the treatment or the image.

Body molds, head masks, or other devices can be constructed for an individual patient to make it easier for the patient to remain still.

Temporary skin marks and even tattoos help position the patient accurately.

Patients who receive radiation to the head may need a mask.

The mask helps prevent the head from moving so that the patient is in the same position for each treatment.

After the simulation, the radiation oncologist determines the exact area to be treated, the total radiation dose to the tumor, the quantity allowed for normal tissues around cancer, and the safest angles (paths) for the tumor. Radiation supply.

Staff working with the radiation oncologist (including physicists and dosimetrists) use sophisticated computers to design the details of the exact radiation plan that will be used.

After approving the plan, the radiation oncologist authorizes the start of treatment.

On the first day of treatment, and generally, at least once a week, many controls are performed to ensure that the treatments are delivered exactly as planned.

Radiation doses for cancer treatment are measured in a gray unit (Gy), which measures the amount of radiation energy absorbed by 1 kilogram of human tissue.

Different doses of radiation are needed to kill different types of cancer cells.

Radiation can damage some types of normal tissue more quickly than others. For example, the reproductive organs (testes and ovaries) are more sensitive to radiation than bones.

The radiation oncologist takes all this information into account during treatment planning.

Suppose an area of ​​the body has previously been treated with radiation therapy. In that case, it is possible that a patient can not receive radiation therapy in that area a second time, depending on the amount of radiation administered during the initial treatment.

Suppose one area of ​​the body has already received the maximum safe dose of radiation. In that case, another location could be treated with radiation therapy if the distance between the two areas is large enough.

The area selected for treatment usually includes the entire tumor plus a small amount of normal tissue surrounding the tumor.

Normal tissue is treated for two main reasons:

  • To take into account the body’s movement of respiration and the regular activity of organs within the body, which can change the location of a tumor between treatments.
  • To reduce the likelihood of tumor recurrence of cancer cells that have spread to normal tissue near cancer (called the microscopic local spread).


Systemic radiation therapy uses a radioactive substance, administered orally or in a vein that travels through the tissues through the blood.

The type of radiation therapy prescribed by a radiation oncologist depends on many factors, including:

  • The size of the cancer
  • In what part of the body is cancer found
  • The proximity of healthy tissues that are sensitive to radiation to cancer.
  • The type of cancer
  • How far in the body the radiation should travel.
  • The general health and medical history of the patient.
  • If the patient takes other treatments for cancer.
  • Patient’s age
  • Other medical conditions

According to a new report, community oncologists play an integral role in referring patients and adopting new treatment options for cancer.

These treatment options include CAR-T cell therapies and genomic and biosimilar drugs.

Most oncologists (51%) see CAR-T cell therapy as an innovative approach to cancer treatment, but barriers such as cost, toxicity, and complex administration can lead to slow absorption.

With three recently approved targeted therapies for acute myeloid leukemia (AML), most oncologists (85%) routinely prescribe genetic tests for patients with AML, and a growing number (31%) are now referring patients with AML to medical centers academics to receive treatment.