Science Fair Project Encyclopedia
- Please refer to cancer for the biology of malignant disease, as well as a list of malignant diseases.
Oncology is the medical study and treatment of cancer. A physician who practices oncology is an oncologist. The term is from the Greek onkos, meaning bulk, mass or tumor, and the suffix -ology, meaning "study of".
Oncology is concerned with:
- The diagnosis of cancer
- Therapy (e.g. surgery, chemotherapy, radiotherapy and other modalities)
- Follow-up of cancer patients after successful treatment
- Palliative care of patients with terminal malignancies
- Ethical questions surrounding cancer care
- Screening efforts:
- of populations, or
- of the relatives of patients (in types of cancer that are thought to have a heritable basis, such as breast cancer).
The oncologist often coordinates the multidisciplinary care of cancer patients, which may involve physiotherapy, counselling, clincal genetics, to name but a few. On the other hand, the oncologist often has to liaise with pathologists on the exact biological nature of the tumor that is being treated.
The most important diagnostic tool remains the medical history: the character of the complaints and any aspecific symptoms (fatigue, weight loss, unexplained anemia, paraneoplastic phenomena and other signs). Often a physical examination will reveal the location of a malignancy.
Diagnostic methods include:
- Biopsy, either incisional or excisional;
- X-rays, CT scanning, MRI scanning, ultrasound and other radiological techniques;
- Scintigraphy, Positron emission tomography and other methods of nuclear medicine;
- Blood tests, including Tumor markers, which can increase the suspicion of certain types of tumors or even be pathognomonic of a particular disease.
Generally, a "tissue diagnosis" (from a biopsy) is considered essential for the proper identification of cancer. When this is an impossibility, empirical therapy (without an exact diagnosis) is the only remaining possibility.
Occasionally, a primary tumor cannot be found. This situation is referred to as "unknown primary". Again, empirical therapy, along with specialized imaging (such as 18-FDG PET) might prove of some benefit.
It depends completely on the nature of the tumor identified what kind of therapeutical intervention will be necessary. Certain disorders will require immediate admission and chemotherapy (such as ALL or AML), while others will be followed up with regular physical examination and blood tests.
Often, surgery is attempted to remove a tumor entirely. This is only feasible when there is some degree of certainty that the tumor can in fact be removed. When it is certain that parts will remain, surgery is often impossible, e.g. when there are metastases elsewhere, or when the tumor has invaded a structure that cannot be operated upon without risking the patient's life. There are a few exceptions: occasionally, surgery can improve survival even if not all tumour tissue has been removed; the procedure it referred to as "debulking" (i.e. reducing the overall amount of tumour tissue). The risks of surgery must be weighed up against the benefits.
Chemotherapy and radiotherapy are used as a first-line therapy in a number of malignancies, such as Hodgkin's lymphoma. More often, however, they are used as adjuvants, i.e. when the tumor has already been completely removed surgically but there is a reasonable statistical risk that it will recur. Please refer to the respective articles for details on these treatment modalities.
A large segment of the oncologist's workload is the following-up of cancer patients who have been successfully treated. As cancer therapy becomes more coordinated, early identification of recurrence will often lead to better survival and quality of life. It depends on the nature of the cancer whether the follow-up lasts a number of years (often 10 years) or remains "life long".
A specialized area of oncology is that of "secondary cancer", tumors caused by treatment for a different cancer. The rate of secondary cancer is improving as chemotherapy treatment schedules are becoming less toxic, but on the whole the incidence of cancer in previous cancer patients is substantially higher than in the general population.
Although 50% of all cancer cases diagnosed achieve curation, a large number of cancer patients will die from the disease. Although in many respects palliative care has matured into a separate specialism, oncology still provides specific guidance and, occasionally, experimental therapies. The use of the latter is not always advised; rather, the patient is encouraged to learn to "live with [approaching] death", when every therapeutical possibility has been attempted.
The oncologist is often faced with ethical questions and dilemmas, e.g. whether to tell a patient about the real prognosis of his/her disease, whether to suggest a highly experimental therapy, and how to properly address the patient's wish to die quickly (with or without euthanasia).
Progress and research in oncology
There is a tremendous amount of research being conducted on all frontiers of oncology, ranging from cancer cell biology to chemotherapy treatment regimens and optimal palliative care and pain relief. This makes oncology an exciting and continuously changing field.
Therapeutic trials often involve patients from many different hospitals in a particular region. In the UK, patients are often enrolled in large studies coordinated by the Medical Research Council (MRC, www.mrc.ac.uk) or the European Organisation for Research and Treatment of Cancer (EORTC, www.eortc.be).
See main article: Alternative medicine
Many other types of therapy have been tried with cancer patients. Some of these have been discredited by the medical community, such as amygdalin, also known as laetrile, an extract of apricot pits. Other herbal preparations are being tried by various practitioners. Some physicians have claimed significant success with a modified means of delivering chemotherapy, termed IPT or insulin potentiation therapy.
Other efforts have centered on trying to bolster the body's immune system's ability to deal with the cancer. Unfortunately, many cancers present surface configurations that exactly mimic their original healthy parent cells, so that most immunotherapies are useless against them.
Some patients also use what are known as "adjunctive therapies ", including such practices as visualization. While these are largely not proven to be effective, they are mostly at least harmless and often supportive of the patient's state of mind while they are undergoing medical therapies.
- Alternative medicine
- Experimental cancer treatment
- List of oncology-related terms
- List of cancer patients
- Cytoluminescent Therapy
- Performance status
- Important publications in oncology
- Vickers, A. Alternative Cancer Cures: "Unproven" or "Disproven"? CA Cancer J Clin 2004 54: 110-118. Full text online
- American Cancer Society
- BC Cancer Agency
- Canadian Cancer Society
- Cancer Research UK
- International Agency for Research on Cancer
- MacMillan cancer relief
- National Cancer Institute
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