Reviewed by: BD Editors

Oncology Definition

Oncology is the study of cancer. Cancer is a disease in which cells reproduce uncontrollably, forming lumps called tumors that may grow and spread to other parts of the body. The word oncology comes from the Greek words onkos, meaning “tumor”, and logos, meaning “study”. An oncologist is a doctor that treats cancer.

History of Oncology

The Ancient Egyptians were one of the first known cultures to describe what we now know to be cancer. The Edwin Smith Papyrus, a remnant of part of an ancient Egyptian medical textbook dating back to 3000 B.C., describes treating tumors by cauterization with a tool known as a “fire drill”. The papyrus also mentioned that there was no cure. In addition, some Ancient Egyptian mummies show signs of having had cancer, such as fossilized bone tumors and bone destruction from cancer in the head and neck.

The Greek physician and “Father of Medicine”, Hippocrates, was the first to use the term carcinoma to describe tumors in the 4th Century B.C. Carcinoma came from the words karkinos, meaning “crab”, and –oma, meaning “swelling”. Hippocrates may have chosen this word because because the thin projections of cells spreading out from a tumor made it look like a crab, or because tumors are hard like a crab shell. The Roman philosopher Celsus was the first to use the term cancer. Cancer is the Roman word for crab, translated from the Greek.

At that time, and for centuries afterward, little was known about cancer or how to treat it. It wasn’t until the Scientific Revolution in the 16th Century that people began to understand more about the human body and its workings, thus paving the way for studying cancer. John Hunter, a Scottish surgeon who lived during the 18th Century, was the first to suggest that some cancers could be cured by surgery. Hunter was referring to cancers that had not yet spread to other parts of the body. In addition, the development and widespread use of the microscope in the 19th Century provided scientists with tools to study cancer at the cellular level. In fact, it was not known until the 19th Century that cancer was actually made up of cells. Hippocrates believed cancer resulted from an excess of black bile, and later on, biologists believed that cancer formed from lymph, the body fluid that contains white blood cells. Even after cancer had been shown to be made up of cells, scientists believed that cancer spread like a liquid. The German surgeon Karl Thiersch showed that cancer is spread through cells via metastasis. When a cancer metastasizes, cells break away from it and travel through the blood or lymph to other parts of the body, forming new tumors.

Cancer screening tests such as the Pap smear, which tests for cervical cancer, and the mammogram, which tests for breast cancer, were developed and put into widespread use in the 20th Century. The American Cancer Society recommends that all individuals be tested for cancer based on their age and sex. Also in the 20th Century, radiation therapy, chemotherapy, hormone therapy, and immunotherapy began to be developed and are now widely used to treat cancer. Another type of cancer treatment was developed in the late 1990s in the form of monoclonal antibodies. Monoclonal antibodies mimic a person’s immune system and are targeted to specific cancer cells to induce an immune response. Which each passing year, our knowledge of cancer and its treatment increases.

Types of Oncologists

The three main types of oncologists are medical, surgical, and radiation oncologists. These types are quite self-explanatory. Medical oncologists use therapies such as chemotherapy and immunotherapy to treat cancer. Surgical oncologists perform surgical operations in order to remove tumors. Radiation oncologists use radiation to treat cancer. In addition, an oncologist may specialize in treating a certain type of cancer. For example, hematologists specialize in treating blood cancers like leukemia. Others may specialize based on age group; a pediatric oncologist, for example, treats cancer in children.

Examining X-Rays of a Cancer Patient
This oncologist is looking at a patient’s x-rays.

Oncology Careers

Oncologists are physicians. To become an oncologist, one must attend medical school following the completion of a bachelor’s degree with a premed track. Often, undergraduates who want to go on to medical school major in biology in college. However, one may major in virtually any subject as long as the prerequisites for medical school are met; this usually involves courses in biology, organic chemistry, physical chemistry, physics, and calculus, among others. Taking advanced cell biology courses would also be helpful for someone who wants to become an oncologist. Radiologists, who specialize in using medical imaging techniques to treat diseases such as cancer, are also physicians. Like oncologists, radiologists must go to medical school and then complete a residency.

Other oncology careers that do not require medical school, but do require specialized training include being an oncology nurse, a clinical nurse specialist, an oncology social worker, or a medical physicist (who administers chemotherapy). In addition, there are also careers available in oncology for those with bachelor’s degrees. Most radiation therapists, who perform the work of administering radiation treatments to patients, have bachelor’s degrees or even two-year associate’s degrees in radiation therapy.

Oncologists may work closely with cancer researchers, but cancer researchers are not considered oncologists (unless they are both a doctor and a researcher, which requires the completion of both MD and PhD degrees). Oncologists diagnose, treat, and help prevent cancer, and interact directly with patients, while cancer researchers perform research in a laboratory setting. The interaction of all of these medical professionals is needed to treat a cancer patient, from developing chemotherapy drugs to diagnosing cancer to administering treatment.


  • n.a. (n.d.). “History of Oncology.” Massachusetts Medical Society. Retrieved 2017-06-16 from https://resident360.nejm.org/content_items/283#content-top.
  • n.a. (n.d.) “NCI Dictionary of Cancer Terms: Metastasize.” National Cancer Institute. Retrieved 2017-06-17 from https://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=46283.
  • Cancer.net Editorial Board (2015-11). “Types of Oncologists.” American Society of Clinical Oncology. Retrieved 2017-06-16 from http://www.cancer.net/navigating-cancer-care/cancer-basics/cancer-care-team/types-oncologists.
  • Markel, Howard (2010-10-22). “Science Diction: The Origin of the Word ‘Cancer’”. Interviewed by Ira Flatow. NPR. Retrieved 2017-06-17 from http://www.npr.org/templates/story/story.php?storyId=130754101.
  • Santiago, Andrea Clement (2016-11-22). “Medical Careers in Oncology.” Verywell. Retrieved 2017-06-17 from https://www.verywell.com/medical-careers-in-oncology-3970197.

Cite This Article

Biologydictionary.net Editors. "Oncology." Biology Dictionary, Biologydictionary.net, 23 Jun. 2017, https://biologydictionary.net/oncology/.
Biologydictionary.net Editors. (2017, June 23). Oncology. Retrieved from https://biologydictionary.net/oncology/
Biologydictionary.net Editors. "Oncology." Biology Dictionary. Biologydictionary.net, June 23, 2017. https://biologydictionary.net/oncology/.

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