what are the environmental factors that can lead to neoplasms?
- Infectious agents
- Smoking
- Alcohol consumption
- Diet
- Obesity
- Reproductive history
- Environmental carcinogens
Environmental Factors of cancer: infectious agents
- Almost 15% of all cancers worldwide caused (directly or indirectly) by infectious agents
- Human papillomavirus (HPV) and cervical carcinoma and some head and neck
cancers
Environmental Factors of cancer: smoking
Established role in cancer of the lung (90%), mouth, pharynx, larynx, esophagus,
pancreas, and bladder
Environmental Factors of cancer: Alcohol consumption
- Alcohol and increased risk of carcinomas of the oropharynx, larynx, and esophagus
- Alcoholic cirrhosis and risk for hepatocellular carcinoma
- Synergistic effects of alcohol and tobacco
Environmental Factors of cancer: diet
- Wide geographic variation in the incidences of colerectal carcinoma, prostate
carcinoma, and breast carcinoma due to differences in diet
- Low-fiber diet and high-fat diet and increased risk for some cancers
Environmental Factors of cancer: Obesity
- Strongly association of weight with cancer risk
- Higher death rates from cancer in overweight patients compared with slimmer
counterparts
Environmental Factors of cancer: Reproductive history
Lifelong cumulative exposure to estrogen and increased risk of cancers of the breast
and endometrium
Asbestos causes what kinds of cancer?
Lung , mesothelioma, esophagus
Benzene causes what kinds of cancer?
Leukemia, Hodgkin lymphoma
Cadmium causes what kinds of cancer?
Prostate
Nickel causes what kinds of cancer?
Lung and oropharyngeal carcinoma
Radon causes what kinds of cancer?
Lung
Second-hand tobacco smoke causes what kinds of cancer?
Oropharyngeal, lung, breast, kidney
Wood dust; leather dust causes what kinds of cancer?
Maxillary sinus adenocarcinoma
Ultraviolet light causes what kinds of cancer?
, Skin
Therapeutic radiation causes what kinds of cancer?
Sarcoma of tissue in field of radiation: osteosarcoma, fibrosarcoma
Cancer in older adults
• Frequency of cancer increases with age.
• Most carcinomas occur in people >55 yrs old.
Cancer in children
• Cancer types very different from adults
• Leukemias, CNS tumors, rhabdomyosarcoma, neuroblastoma, retinoblastoma
Acquired Predisposing Conditions for cancer
- Chronic inflammation
- Precursor lesions
- Immunodeficiency states
Chronic inflammation
associated with increased cellular replication → risk for accumulating the genetic
lesions leading to carcinogenesis
Precursor lesions
metaplasia in Barrett esophagus, squamous metaplasia of the bronchial mucosa,
leukoplakia (showing dysplasia) of the oral cavity
Immunodeficiency states
increased risk for cancers, especially those caused by oncogenic viruses
what causes Asbestosis, silicosis and what cancer can come from it?
Asbestos fibers, silica particles, can cause Mesothelioma, lungcarcinoma
what cancer can come from inflammatory bowel disease?
Colerectal carcinoma
what causes Reflux esophagitis, Barrett esophagus and what cancer can come
from it?
Gastric acid, can cause Esophageal carcinoma
what cancer can come from Sjogren syndrome?
MALT lymphoma
what causes Gastritis/ulcers and what cancer can come from it?
Helicobacter pylori, can cause Gastric adenocarcinoma
what causes Hepatitis and what cancer can come from it?
Hepatitis B and/or C virus, can cause Hepatocellular carcinoma
long summary of epidemiology of cancer
- The incidence of cancer varies with geography, age, race, and genetic background.
Cancers are most common in adults older than 60 years of age, but occurs in adults at
all ages and in children and infants. The geographic variation is thought to mainly stem
from different environmental exposures.
- Important environmental factors implicated in carcinogenesis include infectious agents,
smoking, alcohol, diet, obesity, reproductive history, and exposure to environmental
carcinogens.
- The risk of cancer is increased by reparative proliferations caused by chronic
inflammation or tissue injury, certain forms of hyperplasia, and immunodeficiency.
- Interactions between environmental factors and genetic factors may be important
determinants of cancer risk.