Resources

Glossary

A

  • Aflatoxin B1 (AFB1)

    A harmful, cancer-causing chemical made by certain types of Aspergillus mold that may be found on poorly stored grains and nuts. Consumption of foods contaminated with aflatoxin is an important risk factor for hepatocellular (liver) cancer.

  • Age-specific rate

    A rate for a specified age group, in which the numerator and denominator refer to the same age group.

  • Age-standardization

    A technique that allows comparison of incidence (or mortality) rates between populations, adjusting for any differences in their respective age distributions.

  • Asbestos

    A natural material that is made of tiny fibers and used in insulation and as a fire retardant. Asbestos exposure is an important risk factor for cancer, especially mesothelioma (lining of the chest, abdomen and heart) and also lung cancer.

B

  • Benign tumor

    An abnormal growth that is not cancer and does not spread to other areas of the body.

  • Beta-naphthylamine

    A synthetic organic compound formerly used as an intermediate in some manufacturing processes, and an important risk factor for bladder cancer. Its production and commercial use, with the exception of limited laboratory use, has been banned in most countries.

  • Body mass index (BMI)

    A measure of a person’s weight in relation to his or her height, calculated as weight in kilograms divided by height in meters squared.

C

  • Cancer

    A disease in which abnormal cells divide uncontrollably. Cancer cells can invade nearby tissues and spread through the bloodstream and lymphatic system to other parts of the body.

  • Cancer registry

    An institution that performs the systematic collection and maintenance of a file or register of all cancer cases occurring in a defined population. Registries continuously and systematically collect information from various data sources on the personal characteristics of cancer patients (e.g. age, sex, and race) and the clinical and pathological characteristics (e.g. stage, histologic classification) of the cancers.

  • Cancer screening programs

    Programs organized at a national or regional level that aim to decrease the incidence and mortality of a specific type of cancer by identifying precancerous lesions or tumors at an early stage, when they can be effectively treated. Programs usually have

  • Carcinogen

    Any agent —chemical, physical or biological— that causes cancer. Examples include tobacco smoke, asbestos, human papillomavirus (HPV), and ultraviolet (UV) radiation.

  • Carcinoma

    A cancerous tumor that begins in the lining layer (epithelial cells) of organs. At least 80% of all cancers are carcinomas.

  • Chemotherapy

    Treatment with a drug or drugs to destroy cancer cells. Chemotherapy may be used, either alone or in combination with surgery or radiation treatment, to treat cancer when it is at an early stage, when the cancer has spread, when the cancer has come back (recurred), or when there is a strong chance that the cancer could recur.

  • Colonoscopy

    Examination of the large bowel with a long, flexible, lighted tube called a colonoscope. The physician looks for polyps or early cancers during the exam, and removes them using a wire passed through the colonoscope.

  • Computerized tomography (CT)

    A series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized axial tomography (CAT) scan. A special kind of CT machine, the spiral CT, has been used to look for early lung cancer.

D

  • Diagnosis

    The process of identifying a disease by its signs and symptoms, as well as medical tests and tissue sampling and examination as needed.

  • Dioxins

    Organic chemical byproducts of industrial processes; considered highly toxic environmental pollutants due to their effects on the immune and endocrine systems and on encouraging tumor growth.

  • Direct costs

    Expenditures for medical procedures and services associated with the treatment and care of people with cancer.

E

  • Electron accelerator machines

    Used in medical radiation therapy, these machines accelerate tiny charged particles called electrons, and deliver uniform doses of high-energy x-rays to the region of the patient’s tumor. These x-rays can destroy the cancer cells while sparing the surrounding normal tissue.

  • Endometrial cancer

    Cancer of the layer of tissue that lines the uterus.

  • Epidemic

    Occurrence of an illness, condition, or behavior that affects many people in the same region during a specified period of time. To constitute an epidemic, this occurrence must exceed normal occurrence of the disease in the region.

F

  • Fecal occult blood test (FOBT)

    A test used to screen for large bowel cancer. It looks for blood in the stools, the presence of which may be a sign of cancer.

H

  • Hazard vs. Risk

    An agent is considered a cancer hazard if it is capable of causing cancer under some circumstances. However, it does not indicate the level of risk associated with exposure. The cancer risk associated with substances or agents assigned the same classification may be very different, depending on factors such as the type and extent of exposure and the strength of the effect of the agent.

  • Helicobacter pylori (H. pylori)

    A type of bacterium that causes inflammation and ulcers in the stomach or small intestine. People with H. pylori infections may be more likely to develop cancer in the stomach.

  • Hematopoietic system

    Organs and tissues involved in the production of blood, including the bone marrow, lymph nodes, spleen, and tonsils.

  • Hepatitis B and C viruses (HBV and HCV)

    Viruses that cause hepatitis, a condition that is characterized by inflammation of the liver. Long-term infection may lead to cirrhosis (scarring of the liver) and liver cancer. Persons infected with HCV may also have an increased risk for certain types of non-Hodgkin lymphoma.

  • Hepatocellular carcinoma

    The most common type of cancer originating in the liver.

  • High-/middle-/low-income country

    For the 2014 fiscal year, according to the World Bank, a high-income country has a gross national income (GNI) per capita of more than US$12,616; a middle-income country between US$1035 and US$12,616; and a low-income country less than US$1035.

  • Hormone replacement therapy (HRT)

    Hormones (estrogen, progesterone, or other types) given to women after menopause to replace the hormones no longer produced by the ovaries. HRT can be a risk factor for cancers of the endometrium and breast.

  • Human development index (HDI)

    A measure of health, education and income at the country level produced by the United Nations Development Programme (UNDP) as an alternative to purely economic assessments of national progress, such as GDP growth. All 2020 estimates of cancer burden use HDI based on the UNDP’s Human Development Report 2021-2022

  • Human herpesvirus 8 (HHV-8)

    A type of virus that causes Kaposi sarcoma. Patients with acquired immunodeficiency syndrome frequently suffer from HHV-8-associated diseases. Infection with HHV-8 can also cause certain types of lymphoma and severe lymph node enlargement, known as Castleman's disease. HHV-8 is also known as Kaposi sarcoma-associated herpesvirus, or KSHV.

  • Human immunodeficiency virus (HIV)

    The virus that causes acquired immune deficiency syndrome (AIDS). It is transmitted through blood and other body fluids, and infants born to infected mothers may also become infected. Infection with both HIV and HHV-8 increases the risk of developing Kaposi sarcoma.

  • Human papillomavirus (HPV)

    A type of virus that can cause abnormal tissue growth (for example, warts) and other changes to cells. Long-term infection with certain types of human papillomavirus (e.g., types 16 and 18) can cause cervical cancer. HPV is also a risk factor for anal, vaginal, vulvar, penile, oropharyngeal, and squamous cell skin cancers. It is transmitted through sexual contact.

I

  • Incidence

    The number of new cases arising in a given period in a specified population. This information, collected routinely by cancer registries, can be expressed as an absolute number of cases per year or as a rate per 100,000 persons per year.

K

  • Kaposi sarcoma

    A type of cancer characterized by the abnormal growth of blood vessels that develop into lesions on the skin, lymph nodes, lining of the mouth, nose, and throat, and other tissues of the body. It is caused by human herpesvirus-8 (HHV-8). The risk of developing Kaposi sarcoma in a person who has HHV-8 increases significantly if the person is also infected with human immunodeficiency virus (HIV).

  • Keratinocyte (nonmelanoma) skin cancer

    Also known as basal or squamous cell skin cancer. A cancer that occurs in keratinocyte cells, which are located in the epidermis (top layer of skin) and are responsible for producing keratin. Keratinocytes are divided into squamous cells on the surface of the epidermis and basal cells located within the deeper basal layer of the epidermis.

L

  • Leukemia

    A cancer of the blood or blood-forming organs.

  • Lead time bias

  • Lumpectomy

    Surgery to remove a breast lump or tumor and a small amount of surrounding normal tissue.

  • Lymphoma

    A cancer of the lymphatic system. The lymphatic system is a network of thin vessels and nodes throughout the body. The two main types of lymphoma are Hodgkin lymphoma (or disease) and non-Hodgkin lymphoma.

M

  • Malignant tumor

    A mass of cancer cells that may invade surrounding tissues or spread (metastasize) to distant areas of the body. Synonymous with cancer.

  • Melanoma

    A cancerous (malignant) tumor that begins in the cells that produce the skin coloring (melanocytes). Melanoma is almost always curable in its early stages. However, it is likely to spread, and once it has spread to other parts of the body the likelihood of cure decreases.

  • Menarche

    The first menstrual period, usually occurring during puberty.

  • Menopause

    The time period marked by the permanent cessation of menstruation, usually occurring between the ages of 45 and 55 years.

  • Metastasis

    The distant spread of cancer from its primary site to other places in the body.

  • Morbidity

    Any departure from physiological or psychological well-being. Measures of morbidity for people living with cancer may include disability, pain, time away from work, or days spent in the hospital.

  • Mortality

    The number of deaths occurring in a given period in a specified population. It can be expressed as an absolute number of deaths per year or as a rate per 100,000 persons per year.

N

  • Net survival

    The probability of surviving cancer in the absence of other causes of death.

  • Neoplasm

    An abnormal growth (tumor) that starts from a single altered cell; a neoplasm may be benign or malignant. Cancer is a malignant neoplasm.

  • Neuroblastoma

    Cancer that arises in immature nerve cells; affects mostly infants and children.

O

  • Overweight/obese

    Persons who are considered overweight have a body mass index (BMI) greater than 25; a BMI greater than 30 is considered obese.

P

  • Particulate matter

    Microscopic solid or liquid particles associated with the atmosphere that can penetrate the lungs and cause damage that can lead to lung cancer. Particulate matter can be naturally occurring (e.g. originating from volcanoes or dust storms) or synthetic (e.g. vehicle emissions). The smallest class of particulate matter (<2.5 micrometers diameter) is the deadliest.

  • Palliative care

    An approach that aims to improve the quality of life for patients and families facing the problems associated with life-threatening cancers. It provides for prevention and relief of suffering through treatment for pain and other symptoms as well as through spiritual and psychosocial support, at the time of cancer diagnosis, through the end of life, and during family bereavement.

  • Prevalence

    The number of persons in a defined population who have been diagnosed with a specific type of cancer, and who are still alive at the end of a given year (the survivors). Five-year prevalence limits the number of patients to those diagnosed in the past 5 years. It is a particularly useful measure of cancer burden because for most cancers, patients who are still alive five years after diagnosis are usually considered cured. However, exceptions to this include breast cancer patients, who continue to die from the disease 5 years after diagnosis.

  • Prognosis

    Prediction of the course of cancer, and the outlook for a cure of the cancer.

R

  • Radiotherapy

    The use of radiation treatment to kill cancer cells or stop them from dividing.

  • Radon

    A radioactive gas that is released by uranium—a substance found in soil and rock—and is an important risk factor for lung cancer.

  • Rate

    see Incidence and Mortality

  • Rate ratio

    A measure to compare the incidence rates, person-time rates, or mortality rates of two groups.

  • Retinoblastoma

    A rare form of eye cancer that affects the retina of infants and young children.

S

  • Sarcoma

    A cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

  • Sigmoidoscopy

    An examination to help find cancer or polyps within the rectum and distal part of the colon. A slender, hollow, lighted tube is placed into the rectum, allowing the physician to look for polyps or other abnormalities. The sigmoidoscope is shorter than the colonoscope.

  • Solar irradiation

    See UV radiation.

  • Solid fuels

    Solid materials burned usually for heating purposes, including wood, peat, charcoal, coal, and grains. In certain conditions, excess exposure can be an important risk factor for lung cancer.

  • Survival (rate, estimate)

    The proportion (or percentage) of persons with a given cancer who are still alive after a specified time period (e.g., 1, 3, or 5 years) following a diagnosis.

T

  • Targeted therapy

    A cancer treatment that uses drugs or other substances to identify and attack cancer cells while avoiding harm to normal cells better than many other cancer treatments. Some targeted therapies block the mechanisms involved in the growth and spread of cancer cells. Other types of targeted therapies help the immune system kill cancer cells or deliver toxic substances directly to cancer cells.

U

  • Ultraviolet (UV) radiation

    Invisible rays that are part of the energy that comes from the sun. UV radiation also comes from sun lamps and tanning beds. UV radiation can damage the skin, lead to premature aging, and cause melanoma and other types of skin cancer.

V

  • Vital registration

    The continuous, permanent, compulsory and universal recording of the occurrence and characteristics of vital events (e.g., births and deaths) pertaining to the population, as provided through decree or regulation in accordance with the legal requirements of a country.

W

  • Wilms tumor

    A type of kidney cancer that usually occurs in children younger than 5 years of age.