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 completely depends 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, 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.
Learn more at http://en.wikipedia.org/wiki/Oncology