The following
closely related terms may be used to designate abnormal growths:
Tumor: originally, it meant any abnormal swelling, lump
or mass. In current English, however, the word Tumor has become
synonymous with Neoplasm, specifically solid neoplasm. Note that
some neoplasms, such as Leukemia, do not form tumors.
Neoplasm: the scientific term to describe an abnormal
proliferation of genetically altered cells. Neoplasms can be
benign or malignant:
Malignant neoplasm or malignant tumor: synonymous with
cancer.
Benign neoplasm or benign tumor: a tumor (solid neoplasm)
that stops growing by itself, does not invade other tissues and
does not form metastases.
Invasive tumor is another synonym of cancer. The name
refers to invasion of surrounding tissues.
Pre-malignancy, pre-cancer or non-invasive tumor: A
neoplasm that is not invasive but has the potential to progress
to cancer (become invasive) if left untreated. These lesions
are, in order of increasing potential for cancer, atypia,
dysplasia and carcinoma in situ.
The following terms can be used to describe a cancer:
Screening: a test done on healthy people to detect tumors
before they become apparent. A mammogram is a screening test.
Diagnosis: the confirmation of the cancerous nature of a
lump. This usually requires a biopsy or removal of the tumor by
surgery, followed by examination by a pathologist.
Surgical excision: the removal of a tumor by a surgeon.
Surgical margins: the evaluation by a pathologist of the
edges of the tissue removed by the surgeon to determine if the
tumor was removed completely ("negative margins") or if tumor
was left behind ("positive margins").
Grade: a number (usually on a scale of 3) established by
a pathologist to describe the degree of resemblance of the tumor
to the surrounding benign tissue.
Stage: a number (usually on a scale of 4) established by
the oncologist to describe the degree of invasion of the body by
the tumor.
Recurrence: new tumors that appear a the site of the
original tumor after surgery.
Metastasis: new tumors that appear far from the original
tumor.
Transformation: the concept that a low-grade tumor
transforms to a high-grade tumor over time. Example: Richter's
transformation.
Chemotherapy: treatment with drugs.
Radiotherapy: treatment with radiations.
Adjuvant therapy: treatment, either chemotherapy or
radiotherapy, given after surgery to kill the remaining cancer
cells.
Prognosis: the probability of cure after the therapy. It
is usually expressed as a probability of survival five years
after diagnosis. Alternatively, it can be expressed as the
number of years when 50% of the patients are still alive. Both
numbers are derived from statistics accumulated with hundreds of
similar patients to give a Kaplan-Meier curve.
Cancers are classified by the type of cell that resembles the
tumor and, therefore, the tissue presumed to be the origin of
the tumor. Examples of general categories include:
Carcinoma: Malignant tumors derived from epithelial
cells. This group represents the most common cancers, including
the common forms of breast, prostate, lung and colon cancer.
Sarcoma: Malignant tumors derived from connective tissue,
or mesenchymal cells.
Lymphoma and leukemia: Malignancies derived from
hematopoetic (blood-forming) cells
Germ cell tumor: Tumors derived from totipotent cells. In
adults most often found in the testicle and ovary; in fetuses,
babies, and young children most often found on the body midline,
particularly at the tip of the tailbone; in horses most often
found at the poll (base of the skull).
Blastic tumor: A tumor (usually malignant) which
resembles an immature or embryonic tissue. Many of these tumors
are most common in children.
Malignant tumors are usually named using the Latin or Greek root
of the organ of origin as a prefix and the above category name
as the suffix. For instance, a malignant tumor of the liver is
called hepatocarcinoma; a malignant tumor of the fat cells is
called liposarcoma. For common cancers, the English organ name
is used. For instance, the most common type of breast cancer is
called ductal carcinoma of the breast or mammary ductal
carcinoma. Here, the adjective ductal refers to the appearance
of the cancer under the microscope, resembling normal breast
ducts.
Benign tumors are named using -oma as a suffix with the organ
name as the root. For instance, a benign tumor of the smooth
muscle of the uterus is called leiomyoma (the common name of
this frequent tumor is fibroid). However, some cancers also use
this prefix for historical reasons, examples being melanoma and
seminoma.
Classification Adult cancers
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Cancer
Classification
1. Nomenclature
2. Adult cancers
3. Childhood cancers
Signs and symptoms
Diagnosis
1. Investigation
2. Biopsy
Treatment
1. Surgery
2. Radiation therapy
3. Chemotherapy
4. Targeted therapies
5. Immunotherapy
6. Hormonal therapy
7. Symptom control
8. Complementary and alternative
9. Treatment trials
Prognosis
1. Emotional impact
Causes
1. Chemical carcinogens
2. Ionizing radiation &
Infectious diseases
3. Hormonal imbalances
& Immune system dysfunction
4. Heredity & Other causes
Pathophysiology
1. Epigenetics
2. Oncogenes
3. Tumor suppressor genes
4. Cancer cell biology
4.1 Clonal evolution
4.2 Biological properties of cancer cells
Prevention
1. Modifiable ("lifestyle") risk factors
2. Diet
3. Vitamins
4. Chemoprevention
5. Genetic testing
6. Vaccination
7. Screening
Epidemiology
History
Research |
