Terminology Simplified
Medical Terminology and Cancer
This is the removal of a small section of the tumour, the sample will be analysed by a histopathologist in order to establish a precise diagnosis. Surgical procedure. This may be a needle biopsy, where a very fine needle is used to take a tiny sample of the tumour. Occasionally a surgeon may remove the whole tumour prior to diagnosis; a resection biopsy. is the branch of medicine that specialises in the study and treatment of blood and blood tissues (including bone marrow). A blood count is where the various types cells in the blood are measured. This may aid diagnosis and will be used during treatment to monitor toxicity. The Haematologist may also examine samples from a bone marrow aspiration (needle into the bone) and samples of spinal fluid from a lumbar puncture (needle between the vertebra of the spine). the study of cells relating to the disease. (Histology is the microscopic study of cells and tissues, Pathology is the study of the disease). The histopathologist will determine a precise diagnosis by laboratory tests and microscopic examination of the cells. is where normal cells go through physical changes in order to form the different specialised tissues of the body. Malignant cells may range from well-differentiated (closely resembling the tissue of origin) or undifferentiated or anaplastic (bearing little similarity to the tissue of origin). In general it is the undifferentiated or anaplastic histologies which are more aggressive. A substance in the body that may indicate the presence of cancer. Markers may be secreted by the tumour itself or produced by the body in response to the cancer. Tumour markers may aid diagnosis or give an indicator of how treatment is progressing. These markers are usually specific to certain types of cancer. For example neuron-specific enolase (NSE) is associated with a number of types of cancers, in particular neuroblastoma. Also alphafetoprotein (AFP) levels are often abnormally high in patients with Germ cell tumours. types of medical imaging include:
Not spreading, usually a more mild disease. Cancerous, where the tumour grows uncontrollably and may spread. A tumour restricted to a single site. Where the tumour has spread to other parts of the body beyond the primary site. Metastatic sites (secondaries) my be regional or distant from the original tumour. Staging is where the disease is categorised as to how far it has spread. The precise staging system used will depend on the type of cancer the patient has. In general low stage patients are those with localised tumours that are easily resectable, whilst high stage patients are those with widespread metastases. The treatment given may largely depend upon which stage the patient is at diagnosis. is the expected outcome of a disease and it's treatment, this may be influenced by a variety of factors such as stage, age, site etc. depending on the particular type of cancer. For example, in general a patient with localised disease may have a more favourable prognosis compared to a patient with widespread disease which may be less favourable. is where the symptoms of cancer are no longer present. There is no longer any evidence of the disease using the available investigations. This is when the disease reoccurs after a period in remission. This is where the cancer is resistant to treatment, patient may nevergo into remission, possibly with stable or progressive disease. This is where the patient is staged again after a period of treatment to access the response to therapy. When treatment is complete the periodic visits to the physician are needed to monitor the patient and ensure there has been no recurrence of the disease. Curative treatment - treatment to destroy the cancer. Palliative treatment treatment which relieves the symptoms and pain.
Since the 1960's the development and use of drugs has dramatically improved the prognosis for many types of cancer. Chemo- means chemicals, for most types of cancer chemotherapy will consist of a number of different drugs, this is known as combination chemotherapy. Chemotherapy may be given in a variety of ways; Intravenously (IV) -into a vein is the most common, Intramuscularly (IM) -injection into a muscle, Orally -by mouth, Subcutaneously (SC) -injection under the skin, Intralesionally (IL) -directly into a cancerous area, Intrathecally (IT)-into the fluid around the spine, Topically -medication will be applied onto the skin.
Bone Marrow Transplantation (BMT) The bone marrow is destroyed by high dose chemotherapy and possibly radiotherapy which has been given to kill malignant cells in the body. Healthy matching marrow is then transplanted into the patient.
New approaches - Gene therapy / Immunotherapy In the future patients might be immunised against their own cancers by injecting them with their own tumour cells after they have been genetically modified. The gene-modified tumour cells may encourage the patients own immune system to destroy the cancer cells. Tumour necrosis factor (TNF) and interleukin-2 (IL-2) are substances associated with the immune system which encourage anititumour activity.
Toxicity and Late Effects
Acute Transient. Some side effects may be of short duration. May be sudden or severe.
Chronic
Long lasting. Some side effects may be long lasting e.g. kidney damage.
Neutropenia reduced levels of white cells in the blood. Febrile neutropenia -with fever. WHO toxicity gradings World Health Organisation toxicity grading guidelines. In general these range from grade 0 (none) to grade 4 (life threatening). Late effects It is possible that treatment may have delayed effects e.g. on fertility and growth.
Cancer
Research (i) Basic Science two general approaches include a) the mass screening of thousands of natural substances to see if they have any anti cancer potential; or b) making new compounds in the laboratory e.g. creating analogues of existing drugs (slightly modified chemical structures) designed to make the drug more potent. Pre-clinical testing of drugs. New drugs may be tested on animals to indicate the maximum doses, toxicities and anti cancer potential before they are tested on humans (see phase I trials). experiments may be in vitro (in the test tube) or in vivo (in the body). Much laboratory work uses cell cultures (cells grown in the lab); either from established cell lines or from material collected at biopsy/surgery. There is a great deal of research investigating the mechanisms of how drugs are metabolised and absorbed by the body's cells. Growing knowledge in this field provides the foundations for improving the anticancer potential for existing drugs and for developing new 'designer' drugs. Other work includes research into the machanisms of drug resistance. cytogenetics. During recent years there has been rapid advances in the understanding of tumour biology at the genetic level. Research into the genes associated with different cancers include the identification of oncogenes, tumour supressor genes. This is a key area of cancer research, providing a basis for the development of new treatments and new diagnostic tools. In the future treatment may be more tailored to the biological features of the cancer rather than the standard clinical features.
Cancer
Research (ii) Clinical Trials and Epidemiology Some Studies are experimental which make in intervention e.g. clinical trials, others are observational in which no medical intervention is made. Studies may also be prospective ie. ongoing into the future, or retrospective ie. looking at historical data. In general studies aim to test a hypothesis (theory) by disproving null hypothesis (the opposite theory) e.g. in a trial of a new drug the null hypothesis might be that the new drug has no effect on survival. Tests new types of treatment and aim to define a safe dose that will be used for further studies. This is usually the first testing of a treatment on humans after extensive laboratory work. Recruitment for Phase I trials are usually from patients for whom no other effective therapy is known. Test the anti cancer effects of the new treatment, and include very detailed toxicity investigations. If there is effective antitumour activity, it may be incorporated in a future phase III study. Compare one or more treatments of proven efficacy. Often patients will be randomised between an established 'standard' treatment and a new 'experimental' treatment - it is not known which is the better treatment. Randomisation Treatment is randomly allocated to ensure there is no systematic bias in the results. Ethical approval all new trials have to first be approved by an independent ethics committee. Informed consent is where patients agree to a treatment / randomisation having a reasonable understanding of it. Morbidity Looking at the incidence or prevalence of a disease in a population. Mortality Looking at the death rates caused by a disease. The study of populations. Regional and National cancer registries record all cancers enabling population based studies in cancer to be carried out. Knowing how many people get a type of cancer out of the overall population provides the information needed to calculate incidence rates. Longitudanal Studies are studies where individuals are followed over time. A fixed population (cohort) may be monitored over a number of years. Cross-sectional Studies are studies that are carried out at just one point in time. Case Control Studies are where cases are compared to controls, in order to avoid bias the controls are matched for factors such as age and sex. The aim is to investigate possible associations between certain factors and risk of disease. For example a study investigating smoking and the risk of lung cancer. Meta Analysis is where data from a number of studies are lumped together in order to provide evidence for or against a hypothesis. Cells, Chromosomes and Genes There are more than 100 trillion cells in the human body. Every cell (except the red blood cells) contain the entire human genome that is, all the genetic information necessary to build a human being. This information is encoded in the DNA. Inside the cell's nucleus, DNA is tightly twisted and packed into 23 pairs of chromosomes (one chromosome in each pair comes from each parent). There are 46 human chromosomes which are estimated to contain about 100,000 individual genes that determine each person's inherited human characteristics. Each gene is a segment of double-stranded DNA which holds the information for making a specific molecule, usually a protein. This information (or code) lies in varying sequences of vast numbers of pairs of the four chemical bases that make up the DNA. A change in the sequence (a mutation), or missing sequences (deletion) of these bases may result in an altered protein that does not work properly, or a failure to produce that protein altogether. |
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