Table of ContentsView AllTable of ContentsBasicsTypesSymptomsCausesDiagnosisTreatment
Table of ContentsView All
View All
Table of Contents
Basics
Types
Symptoms
Causes
Diagnosis
Treatment
Oncology is the field of medicine that deal with the diagnosis, treatment, prevention, and early detection ofcancer. Oncologists, in turn, are physicians who treat people with cancer. Cancer has been present through the ages, and is currently the second leading cause of death in the United States.
Fortunately, treatments are improving, and an understanding of cancer on the molecular level has led to improvements in survival as well. We will look at some of the types of oncology professionals, common (and uncommon symptoms), and how it may be diagnosed and treated.
Andrei Orlov / Istockphoto.com / Stock
While the term “Onco” means mass, and “logy” means study, not all cancers cause a mass. There are hundreds of types of cancer that may arise from epithelial cells (such as breast ducts and airways in the lungs), connective tissue (such as sarcomas), or blood cells (such as leukemias and lymphomas).
Even cancers that arise in the same tissue (say, the lungs) differ on a molecular level, such that no two cancers are alike. Unlike benign conditions or tumors, there are several factors that make a cancer cell a cancer cell.
Cancer cellsoften lack sticky substances known as adhesion molecules that keep the cells in place. This allows the cells to spread (metastasize) to other regions of the body. It is the metastasis of tumors, in fact, that is responsible for the majority of deaths from cancer (at least solid tumors).
Cancer Cells vs. Normal Cells: How are They Different?
Incidence and Prevalence
Currently ranked as the second leading cause of death, it’s thought that cancer will affect roughly 1 in 2 men and 1 in 3 women during their lifetime. Survival rates are improving, yet as more people live with cancer, the prevalence ofcancer survivors(and the need for oncology care) will increase.
History
Researchers have noted evidence of cancerous (malignant) tumors in animals even before people inhabited the earth. The earliest written description of the disease was in 3000 BC, but evidence has been noted further back in fossils and mummies.
The Greeks were primarily responsible for the first treatment approaches to the disease, which included the use of a combination of medicine and art.
The History of Cancer: Discovery and Treatment
There are many types of cancer as well as health professionals who treat the disease.
Oncologists
There are three primary types ofoncologistsor physicians who treat people with cancer. These include:
Oncologists/hematologists treat not only people who have cancer but also people who are coping with benign blood-based diseases such as anemia.
Oncologists may also be referred to as either community oncologists; oncologists who work at cancer centers in the community and generally treat all types of cancer, and academic oncologists; physicians who work at the larger cancer centers and often specialize in one type (or one subtype) of cancer.
There are also many subspecialties of oncology. Some of these include:
The Oncology Team
The treatment of cancer increasingly requires a “multidisciplinary” approach, and there are many types of physicians as well as other healthcare professionals who may be part of your treatment team. This team may include:
Types of Cancer
Cancer can affect nearly any type of tissue in the body, but is much more common in some regions than others. The types of cancer can be broken down in many ways, but it can be helpful to look at three basic categories.
Oncology Terminology
For those who are diagnosed with cancer, learning about their disease can feel like learning a foreign language. One term that confuses many people is “invasive cancer.” Having invasive cancer does not mean that cancer has spread or metastasized, but only that a tumor has the potential to spread.
When cells spread beyond the basement membrane, the abnormality is then considered invasive cancer. Even very small tumors, such as a stage IA breast cancer, is thus referred to as “invasive” cancer.
Unlike carcinomas, sarcomas do not have thisprecancerous stage, and therefore screening techniques for early detection cannot detect these cancers at a carcinoma-in-situ stage.
The symptoms of cancer can range from mild (or not present at all) to life-threatening. Some symptoms tend to be specific for certain cancers, whereas others may be present with many types of cancer.
Signs and Symptoms of Cancer
Some signs and symptoms that may be concerning include:
General Symptoms of Cancer
The symptoms of cancer may be nonspecific and associated with a wide range of cancers. Some of these are more common with advanced or metastatic cancers, though they may occur even before other symptoms with early stage tumors.
General symptoms may include:
Surprising Symptoms of Cancer
In addition to the above symptoms, there are several that might not initially raise a person’s suspicion of cancer. This is not a complete list but is a good reminder that people should make an important to see their healthcare provider withanyconcerns about their health. Some surprising symptoms of cancer include:
Blood Clots and Cancer
We have come a long way since Hippocrates first opposed superstitions surrounding cancer and attributed the disease, instead, to natural causes. At the time, however, it was thought to be due to an imbalance of blood, mucus, bile, and other body fluids.
We now know that cancer arises (oncogenesis) after a series of mutations in a normal cell leads to the uncontrolled growth of a tumor. Most often, this includes mutations in bothoncogenes(genes that promote the growth of cells) andtumor suppressor genes(genes that code for proteins that repair damaged cells or eliminate them so they can’t go on to become a cancer).
It’s important to distinguish hereditary (germline) mutations from acquired (somatic) mutations. Most mutations responsible for cancer arise after birth. The fact that these mutations accumulate over time is the reason why cancer becomes more common as we age. In some cases, however, a combination of hereditary and acquired mutations is responsible.
Epigenetics, or non-permanent changes to genes, is also important in the initiation of cancer.
Hereditary vs. Acquired Gene Mutations and Cancer
Hallmarks of Cancer
When talking about the challenges in treating cancer, it’s helpful to talk about some of the hallmarks of cancer. Cancer cells are not just clones of cells that divide out of control, but have many attributes that help a tumor evade the body’s immune system and treatments. Some of these include:
Risk Factors
There are a number of risk factors for cancer. These risk factors do not necessarily cause cancer, but are associated with an increased risk. Fortunately, several of these are avoidable, at least to some degree. In fact, some cancers may even be preventable with vaccinations.
That said, it’s important to note that people can and do develop cancer even if they don’t have any obvious risk factors. For example, lung cancer occurs in people who have never smoked, and lung cancer in never smokers is actually increasing. Risk factors for cancer include:
Age
For many types of cancer, the risk increases with age. This makes sense when considering the causes above and the accumulation of mutations.
Environmental Exposures
A number of environmental exposures have been linked to cancer. Some examples include:
Lifestyle practices:Some of the more modifiable causes of cancer are related to lifestyle practices. Some of these include:
Infectious Diseases
Many people are surprised to hear that roughly 10% of cancers in the United States (and perhaps 25% worldwide) are associated with infectious diseases.
Microorganisms may cause cancer in a number of ways, ranging from direct damage to DNA, to creating chronic inflammation that leads to increased cell turnover (and a greater likelihood of accidents in cell division).
Examples include:
Immunization against hepatitis B and HPV is now available.
Genetics
Genetics are important in many cancer types. In some cases, specific gene mutations lend agenetic predisposition to cancer.Genome-wide association studiesare finding further evidence that the environment may interact with our genes to affect our risk of developing the disease.
Medical Conditions
Many medical conditions are associated with an elevated risk of cancer, ranging from rheumatoid arthritis to inflammatory bowel disease.
Medical Treatments and Medications
While radiation therapy and chemotherapy are used to treat cancer, they are also carcinogens themselves and may raise the risk of cancers in the future. A number of medications, especially immunosuppressive medications, have been associated with a higher risk of cancer.
Diagnosis, Staging, and Screening
The diagnosis of cancer begins with a careful history and physical, including a family history of cancer.
Blood Tests
Depending on the type of cancer, blood tests may raise suspicion. For example, a very high white blood cell count may raise suspicion about possible leukemia. There are also a number of tumor markers that may be increased with different cancers.
Cancer Tumor Markers
Imaging
Imaging tests are frequently used in the diagnosis of cancer. This includes tests such as:
Procedures
Procedures are also frequently used when diagnosing cancer. Some methods include:
Specialized Testing
Special tests are often used to further characterize tumors, such histochemistry, genetic sequencing, and more.
Staging
Once a cancer is diagnosed, in many cases staging is done. Staging is a critical step with many tumors in order to define the best treatment options.
Screening
We currently havecancer screening testsfor a number of different cancers. Some of these include:
Genetic screening may also be done to look for a hereditary predisposition to cancer.
The treatment of cancer has advanced tremendously over the last century, with new modalities being added frequently. One of the most important factors when talking about treatment is to look at the goal of treatment.
In some cases, treatments are used in attempt to cure a cancer. In other cases, it’s hoped that treatment will extend life. Sometimes, treatments may have little chance for inducing a cure or even extending life, but can greatly improve a person’s quality of life while living with cancer.
There are two primary categories of treatment:
Surgery
Surgery often promises the best chance of a cure, though is not always possible. It is the mainstay of treatments for tumors such as breast cancer.
Radiation Therapy and Proton Beam Therapy
Radiation therapy and proton beam therapy can be used in a number of different ways. Most often, they are used before surgery (to decrease the size of a tumor) or after surgery (to reduce the chance of recurrence). Radiation therapy may also be used for palliative reasons, for example, to treat bone pain due to bone metastases.
A specialized type of radiation therapy, stereotactic body radiotherapy (SBRT) or cyberknife is sometimes used as an alternative to surgery. This therapy used high doses of radiation concentrated in a small area of tissue. It is also being used more frequently to treat areas of metastases from a number of tumors.
Chemotherapy
Chemotherapyuses cytotoxic drugs that kill cells that are rapidly dividing. Since it kills any cells that are dividing rapidly (such as hair follicles), side effects are common.
Hormone Therapy
Hormonal therapy is used commonly for cancers in which hormones work as growth factors to stimulate growth of the tumor, such as breast cancer or prostate cancer.
Targeted Therapy
Targeted therapies are treatments that target specific pathways in the growth of a cancer. The growth ofprecision medicinehas come with learning about these pathways and finding ways to intervene.
The completion of the human genome project and the ability to perform genomic testing has resulted in significant improvements in survival for many cancers. Unfortunately, cancers often become resistant to these treatments in time.
Immunotherapy
There are manytypes of immunotherapyranging from immune checkpoint inhibitors to cancer vaccines, to monoclonal antibodies, toCAR T-cell therapyand more. These treatments use the immune system or principles of the immune system to treat cancer, and have been a game-changer with at least some advanced cancers such as lung cancer and melanoma.
Other Treatments
Frombone marrow and stem cell transplantstotumor treating fields, options for addressing cancer continue to expand.
Supportive Care
An Overview of Cancer Treatments
A Word From Verywell
Despite advances in the diagnosis and treatment of cancer, there are many challenges that remain. Fortunately, a few advances not related to treatment are making life better for those who have had to face a diagnosis.
One of these is the growth of psycho-oncology and recognizing that addressing the emotional and spiritual health of people with cancer is as important as treating physical health.
The other major area is that of survivorship. Unlike conditions such as a heart attack where rehabilitation is the standard of care after treatment, there has been little follow-up for cancer survivors; many who are left with long term side effects.
This is changing, and oncology now promises to not only reduce the death rate but also to help people cope with the emotional impact of the diagnosis and move on after treatment with a healthier new normal.
Will Cancer Ever Be Cured?
5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Miller KD, Nogueira L, Mariotto AB, et al.Cancer treatment and survivorship statistics. CA: A Cancer Journal for Clinicians. 2019;69(5):363-385. doi:10.3322/caac.21565Hajdu SI.A note from history: landmarks in history of cancer, part 1.Cancer. 2011;117(5):1097-102. doi:10.1002/cncr.25553Sforzini L, Nettis MA, Mondelli V, Parlante CM.Inflammation in cancer and depression: a starring role for the kynurenine pathway.Review Psychopharmacology (Berl). 2019;236(10):2997-3011. doi:10.1007/s00213-019-05200-8DeVita V, Lawrence T, Rosenberg S.Devita, Hellman, and Rosenberg’s cancer: Principles & practice of oncology. LWW.National Cancer Institute.Risk factors. Infectious.Additional ReadingAmerican Cancer Society.Cancer facts and figures.Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE.Abeloff’s clinical oncology. Philadelphia, PA: Elsevier.Schiller JT, Lowy DR.Virus infection and human cancer: an overview.Recent Results Cancer Res.2014;193:1-10. doi:10.1007/978-3-642-38965-8_1
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Miller KD, Nogueira L, Mariotto AB, et al.Cancer treatment and survivorship statistics. CA: A Cancer Journal for Clinicians. 2019;69(5):363-385. doi:10.3322/caac.21565Hajdu SI.A note from history: landmarks in history of cancer, part 1.Cancer. 2011;117(5):1097-102. doi:10.1002/cncr.25553Sforzini L, Nettis MA, Mondelli V, Parlante CM.Inflammation in cancer and depression: a starring role for the kynurenine pathway.Review Psychopharmacology (Berl). 2019;236(10):2997-3011. doi:10.1007/s00213-019-05200-8DeVita V, Lawrence T, Rosenberg S.Devita, Hellman, and Rosenberg’s cancer: Principles & practice of oncology. LWW.National Cancer Institute.Risk factors. Infectious.Additional ReadingAmerican Cancer Society.Cancer facts and figures.Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE.Abeloff’s clinical oncology. Philadelphia, PA: Elsevier.Schiller JT, Lowy DR.Virus infection and human cancer: an overview.Recent Results Cancer Res.2014;193:1-10. doi:10.1007/978-3-642-38965-8_1
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Miller KD, Nogueira L, Mariotto AB, et al.Cancer treatment and survivorship statistics. CA: A Cancer Journal for Clinicians. 2019;69(5):363-385. doi:10.3322/caac.21565Hajdu SI.A note from history: landmarks in history of cancer, part 1.Cancer. 2011;117(5):1097-102. doi:10.1002/cncr.25553Sforzini L, Nettis MA, Mondelli V, Parlante CM.Inflammation in cancer and depression: a starring role for the kynurenine pathway.Review Psychopharmacology (Berl). 2019;236(10):2997-3011. doi:10.1007/s00213-019-05200-8DeVita V, Lawrence T, Rosenberg S.Devita, Hellman, and Rosenberg’s cancer: Principles & practice of oncology. LWW.National Cancer Institute.Risk factors. Infectious.
Miller KD, Nogueira L, Mariotto AB, et al.Cancer treatment and survivorship statistics. CA: A Cancer Journal for Clinicians. 2019;69(5):363-385. doi:10.3322/caac.21565
Hajdu SI.A note from history: landmarks in history of cancer, part 1.Cancer. 2011;117(5):1097-102. doi:10.1002/cncr.25553
Sforzini L, Nettis MA, Mondelli V, Parlante CM.Inflammation in cancer and depression: a starring role for the kynurenine pathway.Review Psychopharmacology (Berl). 2019;236(10):2997-3011. doi:10.1007/s00213-019-05200-8
DeVita V, Lawrence T, Rosenberg S.Devita, Hellman, and Rosenberg’s cancer: Principles & practice of oncology. LWW.
National Cancer Institute.Risk factors. Infectious.
American Cancer Society.Cancer facts and figures.Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE.Abeloff’s clinical oncology. Philadelphia, PA: Elsevier.Schiller JT, Lowy DR.Virus infection and human cancer: an overview.Recent Results Cancer Res.2014;193:1-10. doi:10.1007/978-3-642-38965-8_1
American Cancer Society.Cancer facts and figures.
Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE.Abeloff’s clinical oncology. Philadelphia, PA: Elsevier.
Schiller JT, Lowy DR.Virus infection and human cancer: an overview.Recent Results Cancer Res.2014;193:1-10. doi:10.1007/978-3-642-38965-8_1
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