Oncology (from the Ancient Greek onkos meaning bulk, mass, or tumor, and the suffix -logy (-λογία), meaning "study of") is a branch of medicine that deals with tumors (cancer). A medical professional who practices oncology is an oncologist.

Oncology is concerned with:

* The diagnosis of any cancer in a person
* 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:
o of populations, or
o of the relatives of patients (in types of cancer that are thought to have a hereditary basis, such as breast cancer)

The most important diagnostic tool remains the medical history: the character of the complaints and any specific symptoms (fatigue, weight loss, unexplained anemia, fever of unknown origin, paraneoplastic phenomena and other signs). Often a physical examination will reveal the location of a malignancy.

Diagnostic methods include:

* Biopsy, either incisional or excisional;
* Endoscopy, either upper or lower gastrointestinal, bronchoscopy, or nasendoscopy;
* X-rays, CT scanning, MRI scanning, ultrasound and other radiological techniques;
* Scintigraphy, Single Photon Emission Computed Tomography, 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.

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 not possible, "empirical therapy" (without an exact diagnosis) may be given, based on the available evidence (e.g. history, x-rays and scans.)

Occasionally, a metastatic lump or pathological lymph node is found (typically in the neck) for which a primary tumor cannot be found. This situation is referred to as "carcinoma of unknown primary", and again, treatment is empirical based on past experience of the most likely origin.

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. A detailed discussion of treatment options according to the type of cancer is at the National Cancer Institute website with sections on adult cancers, pediatric cancers, and supportive care. There is also a section on complementary and alternative methods of treatment.

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, curative 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. Occasionally surgery can improve survival even if not all tumour tissue has been removed; the procedure is referred to as "debulking" (i.e. reducing the overall amount of tumour tissue). Surgery is also used for the palliative treatment of some of cancers, e.g. to relieve biliary obstruction, or to relieve the problems associated with some cerebral tumors. The risks of surgery must be weighed up against the benefits.

Chemotherapy and radiotherapy are used as a first-line radical therapy in a number of malignancies. They are also used for adjuvant therapy, i.e. when the macroscopic tumor has already been completely removed surgically but there is a reasonable statistical risk that it will recur. Chemotherapy and radiotherapy are commonly used for palliation, where disease is clearly incurable: in this situation the aim is to improve the quality of and prolong life.

Hormone manipulation is well established, particularly in the treatment of breast and prostate cancer.

There is currently a rapid expansion in the use of monoclonal antibody treatments, notably for lymphoma (Rituximab), and breast cancer (Trastuzumab).

Vaccine and other immunotherapies are the subject of intensive research.

 

 

There are several sub-specialties within oncology. Moreover, oncologists often develop an interest and expertise in the management of particular types of cancer.

Oncologists may be divided on the basis of the type of treatment provided.[5]

* Radiation oncology: treatment primarily with radiation, a process called radiotherapy.
* Surgical oncology: surgeons who specialize in tumor removal.
* Medical oncology: treatment primarily with drugs, e.g. chemotherapy[6]
* Interventional oncology: interventional radiologists who specialize in minimally invasive image guided tumor therapies.
* Gynecologic oncology: focuses on cancers of the female reproductive system.
* Pediatric oncology: concerned with the diagnosis and treatment of cancer in children

In the United Kingdom and several other countries, oncologists may be either clinical or medical oncologists. The main difference is that clinical oncologists deliver radiotherapy, while medical oncologists do not. (This difference does not apply in North America: the terms, clinical oncologist and medical oncologist are used interchangeably.)

In most countries it is now common that patients are treated by a multidisciplinary team. These teams will meet on regular basis and discuss the patients under their care. These teams consist of the medical oncologist, a clinical oncologist or radiotherapist, a surgeon (sometimes there is a second reconstructive surgeon), a radiologist, a pathologist, an organ specific specialist such as a gynecologist or dermatologist, and sometimes the general practitioner is also involved. These disease oriented teams are sometimes in conflict with the general organisation and operation in hospitals. Historically hospitals are organised in an organ or technique specific manner. Multidisciplinary teams operate over these borders and it is sometimes difficult to define who is in charge.

In veterinary medicine, veterinary oncology is the sub-specialty that deals with cancer diagnosis and treatment in animals.
See also

* AllergoOncology
* Clinical Medicine: Oncology (journal)
* Experimental cancer treatment
* Important publications in oncology
* List of oncology-related terms
* Ocular oncology
* Oncofertility
* Performance status
* Fertility preservation