Oncology
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
- Non-surgical therapy (i.e. chemotherapy, radiotherapy and other modalities)
- Follow-up of cancer patients after succesful treatment
- Palliative care of patients with terminal malignancies
- Ethical questions surrounding cancer care
- Screening 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 pathologistss on the exact biological nature of tumor that is being treated.
Diagnosis
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.
Diagnostical methods include:
- X-rays;
- CT scanning;
- MRI scanning;
- Scintigraphy and other methods of nuclear medicine;
- Positron emission tomography;
- Biopsy (either by fine-needle aspiration or exploratory surgery);
- Blood tests are rarely diagnostic but might help in identifying the location and spread of the tumor;
- Tumor markers, special blood tests that can increase the suspicion of certain types of tumors.
Apart from in diagnosis, these modalities (especially imaging by CT scanning) are often used to determine operability, i.e. whether it is surgically possible to remove a tumor in its entirety.
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, apart with specialized imaging (such as 18-FDG PET) might prove of some benefit.
Therapy
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 acute leukemia), 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 feasable 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: in ovarian carcinoma, 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).
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 adjuvans, 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.
Some tumors are susceptible to immunotherapy.
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