What is oncology?

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The medical specialty that studies tumors, focusing on their causes, their development, and means of treating them.
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Subspecialties: Biochemistry, radiology, radiation and cancer biology, radiation physics, chemotherapy, genetics, surgery, hematology

Cancers treated: All

Training and certification: Several subspecialties exist under the broad umbrella term “oncologist.” Minimally, those pursuing oncological training and certification must possess a recognized medical degree or, in the case of oncological nurses, must be registered nurses.

Among the basic fields in which oncologists practice is surgical oncology, in which board-certified surgeons take special training in biopsy, tumor staging, and tumor resection or removal by surgical means. Another distinct field is pediatric oncology and hematology, in which board-certified pediatricians take special training that focuses on various malignancies frequently found in babies or in children. Medical oncology is a field that attracts internists who complete special oncological training. Yet another field is radiation oncology, which is staffed by radiologists who complete special training directed toward the radiological diagnosis and treatment of malignancies. Gynecological oncology is studied by board-certified gynecologists and obstetricians, while board-certified hematologists may continue their studies with an emphasis on cancers of the blood, such as leukemia.

Specific training in oncology usually involves a residency of two to four years, generally pursued at a recognized cancer center. Such training follows the residency in each candidate’s special field, such as surgery, pediatrics, or radiology.

Certification is granted by such regulatory agencies as the Accreditation Council of Graduate Medical Education, the American Board of Radiology, and the American Board of Pediatrics. Specific oncological training may focus on clinical research, on the integration of oncological training with other medical specialties, on clinical practice, or on a combination of these activities.

Once physicians have received initial certification in their specific fields, they usually must renew this certification at regular intervals. Such renewals may require them to take refresher courses or to pass qualifying examinations in the field. Although it is seldom necessary to withhold the renewal of certification, practicing oncologists must keep abreast of their fields to assure themselves that they will qualify for recertification.

Services and procedures performed: Although cancer is the broad term used to describe the runaway proliferation of malignant cells within the body, this catch-all term is too broad to describe the many types of malignancies that oncologists encounter and are called on to treat. Cancer occurs when masses of tissue, termed neoplasms, behave abnormally, when their growth is out of control to the extent that it poses the possibility of spreading to other organs, a process know as metastasis.

Because a metastasized cancer is more difficult to control than one that is confined to a small area, physicians urge patients to seek immediate medical intervention if any sign of a malignancy is detected. Cancers caught in the early stages usually can be controlled and possibly eliminated through radiation, chemotherapy, surgery, or a combination of these procedures. Early detection is key to controlling and eliminating malignancies.

Oncologists in all subspecialties of oncology are fundamentally concerned with attempting to understand how normal cells mutate into malignant cells. Their research is concentrated on determining the process through which malignancies develop so that they can find means of thwarting such abnormal development.

As oncologists come to understand the process through which normal somatic cells are transformed into malignant cells, they are better equipped than ever before to deal with the inroads of cancer. As knowledge of the molecular biology of cancer proliferates, oncologists have been increasingly able to develop biochemical and genetic means of not only treating malignancies but also anticipating them in patients who are at risk genetically of developing cancer.

Certainly the most effective treatment of cancer is anticipatory and preventive. A family history of cancer may substantially increase the likelihood that a patient will eventually develop cancer, so oncologists can provide preventive treatment to lessen or eliminate such a possibility.

Cancer genes are essentially of two types. Dominant oncogenes, as they are called, are relatively rare. Of the approximately twenty thousand human genes that have been identified, less than one hundred are oncogenes. Such genes increase the ability of cells to divide. When they grow uncontrolled in organisms, they result in both malignant and benign tumors. Anti-oncogenes are designed to suppress tumors. They sometimes undergo a mutation that thwarts the cell’s ability to develop its means of suppressing such tumors.

Through mutation, dominant oncogenes and anti-oncogenes can both serve to cause the generation of cells that are difficult to control. Great progress has been made in understanding the basic molecular factors involved in the development of cancer, giving oncologists the tools, both genetic and biochemical, that they require to diagnose the behavior of neoplasms, or abnormal new cells, and to find ways to treat such cellular growth effectively.

With medical advances and an increased understanding of the role that genetics plays in cellular growth, oncologists have developed sophisticated means of treating abnormalities in the growth of cells, particularly of malignant cells. With the unraveling of some of the mysteries of how deoxyribonucleic acid (DNA) determines cellular growth, oncologists have come to realize that the four nucleotides found in cells (adenine, guanine, cytosine, and thymine) occur in various sequences and that they contain the genetic information required to comprehend the development and configuration of cellular organisms.

The genes provide cells with the information they need to develop the cellular sequence of amino acids needed to build the proteins, the building blocks, required for cells to develop and grow. Dominant oncogenes can distort the division of cells so that instead of an orderly production, a runaway production of cells takes place, resulting in tumors. Oncologists strive to understand the genetic activities of cells and to bring under control any cellular activity that thwarts or threatens the orderly production of cells and causes tumors to form.

Although the primary goal of oncologists is to evaluate malignancies and work either to eliminate them or to greatly reduce their size, an important secondary goal is to offer reassurance to patients and their families and to work assiduously to make patients as comfortable and pain-free as possible in the course of their treatment. Ongoing research in oncology has proliferated greatly in the twenty-first century. Oncologists necessarily strive to keep abreast of it. Whereas major surgery was often indicated for malignancies in the 1980s or 1990s, much treatment of comparable malignancies has become either noninvasive or minimally invasive.

Prolonged radiation therapy with all of its side effects has, in many cases, been replaced by much more benign procedures such as the implantation at the site of the malignancy of radioactive seeds that provide an uninterrupted but much reduced dose of radiation. Such procedures provide a constant bombardment of malignant cells with radiation but reduce substantially the side effects that accompany a more extensive radiological procedure. These means of treating malignancies often permit patients to engage quite normally in their day-to-day activities. In systemic radiation therapy, a patient receives an injection or swallows a radioactive substance.

Related specialties and subspecialties: Initially, many of the patients who consult oncologists do so because they have been referred by internists or family physicians to whom they turned when symptoms begin to appear. Oncologists to whom such patients are referred generally keep in contact with the referring physician, who often continues to see such patients on a regular basis.

Most of the work oncologists do is highly collaborative. Ideally it is carried out at large medical centers staffed by specialists in each of the many subspecialties of oncology. Regardless of the site of a malignancy, a radiation oncologist is necessarily involved in helping determine the extent of radiological treatment and in plotting its course. Oncologists working together make diagnoses and determine the stage of a malignancy, with stages ranging from I to IV. The two higher numbers indicate a malignancy that has metastasized or spread to organs outside the original site of the growth.

Increasingly stage IV malignancies, once considered death sentences, are being treated successfully. Some such growths have been eliminated through radiation or chemotherapy, sometimes combined with surgical intervention. In such cases, the oncologist works closely with radiologists, physical oncologists, geneticists, and surgeons, all of whom have had special training in oncology, to determine an effective course of treatment that can result in eliminating or controlling the malignancy. Even in cases in which there is no cure, the quality and extent of a patient’s life can be considerably enhanced by oncological treatments devised by various specialists in the field.

Cancers exist in so many forms that specialists from many fields, some only ancillary to the medical profession, may be called on to be involved in their treatment. As research increasingly indicates that diet may substantially affect the growth of cancer cells, nutritionists have become involved in working collaboratively with oncologists. Since 1911, when American pathologist Peyton Rous first detected an oncogenical virus in a malignant tumor that grew in a chicken, virologists have worked with oncologists to identify viruses that may be associated with cancer.

Oncologists may also refer patients and those close to them to mental health professionals and social workers to help them cope with the depression and uncertainties that frequently accompany diagnoses of cancer and their subsequent treatment. In cases that are clearly terminal, oncologists may help patients obtain hospice care so that they will be looked after either in their homes or in facilities that are less forbidding and less costly than hospitals.


Abrams, Donald I. Integrative Oncology. 2nd ed. New York: Oxford UP, 2014. Digital file.

De Vita, Vincent T., Samuel Hellman, and Steven A. Rosenberg, eds. Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia: Lippincott, 2014. Print.

Di Saia, Philip J., and William T. Creasman. Clinical Gynecologic Oncology. Philadelphia: Elsevier/Saunders, 2012. Digital file.

Langhorne, Martha E., Janet S. Fulton, and Shirley E. Otto, eds. Oncological Nursing. 5th ed. St. Louis: Mosby Elsevier, 2007. Print.

Lanzkowsky, Philip. Manual of Pediatric Hematology and Oncology. 5th ed. Boston: Academic, 2011. Print.

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Vasilev, Steven A., ed. Perioperative and Supportive Care in Gynelogic Oncology: Evidence-Based Management. New York: Wiley-Liss, 2000. Print.

Organizations and Professional Societies

American Board of Internal Medicine (ABIM) . http://www.abim.org, 510 Walnut Street Suite 1700, Philadelphia, PA 19106-3699

American Board of Obstetrics and Gynecology (ABOG) . http://www.abog.org, 2915 Vine Street, Dallas Texas, 75204.

American Board of Pediatrics (ABP) . https://www.abp.org/, 111 Silver Cedar Road, Chapel Hill, NC 27514.

American Board of Radiology (ABR) . http://www.theabr.org, 5441 East Williams Boulevard, Suite 200, Tucson, AZ 85711.

American Board of Surgery (ABS) . http://www.absurgery.org, 1617 John F. Kennedy Boulevard #860, Philadelphia, PA 19103.

American Society for Therapeutic Radiology and Oncology (ASTRO) . http://www.astro.org, 8280 Willow Oaks Corporate Drive, Suite 500, Fairfax, VA 22031

American Society of Clinical Oncology . http://www.asco.org, 1900 Duke Street, Suite 200, Alexandria, VA 22314.

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