The term oncology literally means a branch of science that deals with tumors and cancers. The word "onco" means bulk, mass, or tumor while "-logy" means study. Oncology is the diagnosis and treatment of malignancies (cancers), including breast, prostate, colon, lung, and ovarian cancers as well as brain tumors, leukemia, lymphoma and many other types of cancer. Oncology is a branch of medicine that deals with the prevention, diagnosis and treatment of cancer. It includes medical oncology (the use of chemotherapy, hormone therapy, and other drugs to treat cancer), radiation oncology (the use of radiation therapy to treat cancer), and surgical oncology (the use of surgery and other procedures to treat cancer).

What is cancer?

Each of the cells of the body have a tightly regulated system that controls their growth, maturity, reproduction and eventual death. Cancer begins when cells in a part of the body start to grow out of control. There are many kinds of cancer, but they all start because of out-of-control growth of abnormal cells.

The three components which have improved survival in cancer are:
1. Prevention - This is by reduction of risk factors like tobacco and alcohol consumption
2. Early diagnosis - Screening of common cancers and comprehensive diagnosis and staging
3. Treatment - Multimodality management by discussion in tumour board and treatment in a comprehensive cancer centre

Cancers are best managed by discussing in multi-disciplinary tumour boards where medical oncologist, surgical oncologist, radiation oncologist, pathologist, radiologist and organ specific oncologists meet to find the best possible management for an individual patient considering the physical, social, psychological, emotional and financial status of the patients. It is very important for oncologists to keep updated of the latest advancements in oncology as changes in management of cancer are quite common. All fit patients whose cancer progresses and no standard of care treatment options are available should be enrolled in a clinical trial.

Bone marrow is the spongy tissue inside some of the bones in the body, including the hip and thigh bones. Bone marrow contains immature cells, called stem cells. Numerous people with blood cancers such as leukemia and lymphoma, sickle cell anemia and other life-threatening diseases, rely on bone marrow or cord blood transplants to survive. Healthy bone marrow and blood cells are needed in order to live. When disease affects bone marrow so that it can no longer function effectively, a marrow or cord blood transplant could be the best treatment option; for some patients it is the only potential cure.Bone marrow is the soft, spongy, gelatinous tissue found in the hollow spaces in the interior of bones.The average weight of this tissue is about 4% of the total body weight, or 2.6 kg in an adult weighing 65 kg. Progenitor cell (stem cell) lines in the bone marrow produce new blood cells and stromal cells. Bone marrow is also an important part of the lymphatic system.

Bone marrow consists of stem cells, which are large, "primitive," undifferentiated cells supported by fibrous tissue called stroma.

Bone marrow is soft, gelatinous tissue that fills the medullary cavities - the centers of bones. There are two types of bone marrow: red bone marrow (also known as myeloid tissue) and yellow bone marrow (fatty tissue). Both types of bone marrow are highly vascular and enriched with numerous blood vessels and capillaries.2The bone marrow makes more than 200 billion new blood cells every day. Most blood cells in the body develop from cells in the bone marrow.

Bone marrow is the soft spongy tissue that lies within the hollow interior of long bones. In adults, marrow in large bones produces new blood cells. Bone marrow forms around 4% of total body weight (around 2.6 kg in a healthy adult).

There are two types of bone marrow:

1. Red marrow that is responsible for producing red blood cells, white blood cells and platelets
2. Yellow marrow consisting mainly of fat cells

Functions of bone marrow

Red blood cells (erythrocytes) carry oxygen to the tissues.
Platelets or thrombocytes (derived from megakaryocytes) help prevent bleeding and aid in clotting of blood.
Granulocytes (neutrophils, basophils and eosinophil's) and macrophages (collectively known as myeloid cells) fight infections from bacteria, fungi, and other parasites. They also remove dead cells and remodel tissue and bones.

B-lymphocytes produce antibodies, while T-lymphocytes can directly kill or isolate invading cells.
RBC live for around 170 days and rest are shorter lived and need to be replenished continuously. An average human requires approximately one hundred billion new hematopoietic cells each day. This is performed by the Hematopoietic Stem Cells (HSCs).

Radiation therapy is the use of high-energy radiation to damage cancer cells' DNA and destroy their ability to divide and grow. It may be delivered using machines called accelerators or via radioactive sources placed inside the patient on a temporary or permanent basis. Radiation therapy can help reduce pain and suffering in patients with advanced cancer.

Radiation therapy uses high-energy radiation to shrink tumors and kill cancer cells,X-rays,Gamma-rays, and charged particles are types of radiation used for cancer treatment.

The radiation may be delivered by a machine outside the body (External Beam radiation theraphy), or it may come from radioactive material placed in the body near cancer cells (internal radiation theraphy,also called brachytheraphy) Systemic radiation theraphy uses radioactive substances, such as radioactive iodine. that travel in the blood to kill cancer cells.About half of all cancer patients receive some type of radiation therapy sometime during the course of their treatment.Preparation for radiation therapy is focused on targeting the radiation dose to the cancer as precisely as possible to minimize side effects and avoid damaging normal cells. Imaging tests may be used to help determine the exact shape and location of your tumor and define its boundaries. Your doctor will give you specific instructions based on the type of exam being performed.

Radiation is energy that comes from a source and travels through some material or through space. Light, heat and sound are types of radiation. The kind of radiation discussed in this presentation is called ionizing radiation because it can produce charged particles (ions) in matter.Ionizing radiation is produced by unstable atoms. Unstable atoms differ from stable atoms because they have an excess of energy or mass or both.

Unstable atoms are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation. The kinds of radiation are electromagnetic (like light) and particulate (i.e., mass given off with the energy of motion). Gamma radiation and X-rays are examples of electromagnetic radiation. Beta and Alpha radiation are examples of particulate radiation. Ionizing radiation can also be produced by devices such as X-ray machines.