Oncology

ALSO KNOWN AS: Cancer medicine

DEFINITION: Oncology is the medical specialty that studies tumors, focusing on their causes, development, and treatments. Although tumors may be cancerous (malignant) or noncancerous (benign), oncologists are largely concerned with the malignant type because they are more life-threatening and present greater medical challenges than benign tumors.

Specialties: Medical oncologists use chemotherapy and other medications to treat patients, surgical oncology specialists treat cancer with surgery, radiology oncology uses radiation to treat patients, and clinical oncologists use various therapies and radiation treatments.

Subspecialties: Pediatric, breast, bone, thoracic, gastrointestinal, geriatric, ocular, dermatological, and gynecological oncology.

Cancers treated: All

Training and certification: Several subspecialties exist under the broad umbrella term oncologist. Those pursuing oncological training and certification must possess a bachelor's degree, take the Medical Competency Aptitude Test (MCAT), and get accepted into medical school. The first two years of medical school are primarily classroom learning, followed by two years of clinical rotations in various medical fields in several locations. Following four years of medical school, students graduate with a doctor of medicine (MD) or osteopathic medicine (DO).

Surgical oncologists attend a five-year surgical residency program and a two or three-year surgical fellowship. If they wish to specialize further, an additional fellowship is required. These years of training provide special training in biopsy, tumor staging, and tumor resection or removal by surgical means. They receive board certification through the American Board of Surgery (ABS). Individuals pursuing radiation oncology attend a five- to six-year residency program where they complete special training for the radiological diagnosis and treatment of malignancies. They receive board certification through the American Board of Radiology (ABR). Medical oncologists complete three years as an internal medicine or pediatrics residency and a three-year oncology fellowship. These doctors receive special training focusing on various malignancies frequently found in babies and children or adults. Medical oncologists receive board certification from the American Board of Internal Medicine (ABIM).

The Accreditation Council of Graduate Medical Education reviews and accredits medical residency and internship programs. This ensures standardization and education and preserves the integrity of medical degrees. In the United States, most states require oncologists to pass the United States Medical Licensing Examination (USMLE) and often a state board exam. If the doctor’s degree is a DO, they may take the Comprehensive Osteopathic Medical Licensing Examination (COMLEX) instead of the USMLE. These governing bodies require medical professionals to renew their certifications regularly, often requiring refresher courses or field examinations. Although it is seldom necessary to withhold certification renewal, practicing oncologists must keep abreast of their fields to ensure they 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 known as metastasis.

Because a metastasized cancer is more difficult to control than one 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 are usually controlled or eliminated through radiation, chemotherapy, surgery, or a combination of these procedures. Early detection is key to controlling and eliminating malignancies.

Oncologists in all oncology subspecialties are fundamentally concerned with attempting to understand how normal cells mutate into malignant cells. Their research focuses on determining how malignancies develop so they can usually thwart such abnormal development.

As oncologists better understand how normal somatic cells transform into malignant cells, they are better equipped to address 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. 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 genetics’ role in cellular growth, oncologists have developed sophisticated means of treating abnormalities in cell growth, particularly 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.

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 cell division so that instead of an orderly production, a runaway production takes place, resulting in tumors. Oncologists strive to understand the genetic activities of cells and to control any cellular activity that thwarts or threatens the orderly production of cells and causes tumors to form.

Although oncologists' primary goal is to evaluate malignancies and work to eliminate or significantly reduce their size, an important secondary goal is to offer reassurance to patients and their families and make patients as comfortable and pain-free as possible during treatment. Ongoing research in oncology has proliferated greatly in the twenty-first century, and oncologists necessarily strive to keep abreast of it. Major surgery was often indicated for malignancies in the 1980s or 1990s, but much treatment of comparable malignancies has become noninvasive or minimally invasive. Prolonged radiation therapy with all of its side effects has, in many cases, been replaced by 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 constantly bombard malignant cells with radiation but substantially reduce the side effects of a more extensive radiological procedure. These means of treating malignancies allow most patients to engage 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: Many patients initially consult oncologists after presenting with symptoms and receiving a referral from their internist or family physician. Oncologists typically keep in contact with the referring physician, who often continues to see the referred patient. An oncologist’s work is highly collaborative. Ideally, it occurs at large medical centers staffed by specialists across oncology subspecialties. Regardless of the site of a malignancy, a radiation oncologist must help determine the extent of radiological treatment and plot its course. Oncologists work together to diagnose and determine the stage of malignancy ranging from I to IV. The two higher numbers indicate a malignancy that has metastasized or spread to nearby organs outside the original site.

Increasingly, stage IV malignancies that were once considered death sentences are being treated successfully with radiation or chemotherapy, sometimes combined with surgical intervention. In such cases, the oncologist works closely with radiologists, physical oncologists, geneticists, and surgeons with special training in oncology to plan an effective course of treatment. Specialists from many fields, some only ancillary to the medical profession, are increasingly involved in cancer treatment. For example, nutritionists are consulted more frequently as the link between diet and the growth of cancer cells is uncovered. Oncologists may also refer patients and those close to them to mental health professionals and social workers to help them cope with depression and the uncertainties that accompany a cancer diagnosis and treatment. In terminal cases, oncological treatments devised by various specialists can enhance the quality and extent of a patient’s life. They may help patients obtain hospice care to receive care in their homes or facilities that are less forbidding and costly than hospitals.

Bibliography

Govindan, Ramaswamy, and Daniel Morgensztern. The Washington Manual of Oncology. 4th ed., Lippincott Wilkins & Wilkins, 2022.

"JAMA Oncology." American Medical Association, jamanetwork.com/journals/jamaoncology. Accessed 20 June 2024.

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

"Oncologist." Cleveland Clinic, 1 Dec. 2021, my.clevelandclinic.org/health/articles/22145-oncologist. Accessed 20 June 2024.

Niederhuber, John E., and Martin D. Abeloff. Abeloff’s Clinical Oncology. 6th ed., Philadelphia, 2020.

Payne, Judith K., and Kathleen Murphy-Ende. Current Trends in Oncology Nursing. 2nd ed., Oncology Nursing Society, 2019.

Rizzo, Phillip A., and David G. Poplack, eds. Principles and Practice of Pediatric Oncology. 7th ed. Lippincott, 2016.

Shimizu, Hideyuki, and Keiichi I. Nakayama. "Artificial Intelligence in Oncology." Cancer Science, vol. 111, no. 5, 2020, pp. 1452-1460. doi:10.1111/cas.14377.

Sperduto, Paul W., and John P. Gibbons. Khan’s Treatment Planning in Radiation Oncology. 5th ed., Wolters Kluwer, 2022. 

Tenenbaum, Ariel. Clinical Oncology: An Encompassing Overview. Nova Science, 2020.

Zevon, Emily. Health Literacy and Communication Strategies in Oncology: Proceedings of a Workshop. National Academies Press, 2020.