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Tumor stroma and extracellular matrix in hypoxia. Tumor hypoxia is the situation where tumor cells have been deprived of oxygen.As a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor with regions where the oxygen concentration is significantly lower than in healthy tissues.
Tissue hypoxia refers to low levels of oxygen in the tissues of the body and the term hypoxia is a general term for low levels of oxygen. [2] Hypoxemia is usually caused by pulmonary disease whereas tissue oxygenation requires additionally adequate circulation of blood and perfusion of tissue to meet metabolic demands. [4]
In cancer types with high survival rates, incidence is usually higher in the developed world, where longevity is also greater. Cancers with lower survival rates are more common in developing countries. [6] The highest cancer survival rates are in countries such as South Korea, Japan, Israel, Australia, and the United States. [7]
Hypoxia differs from hypoxemia and anoxemia, in that hypoxia refers to a state in which oxygen present in a tissue or the whole body is insufficient, whereas hypoxemia and anoxemia refer specifically to states that have low or no oxygen in the blood. [3] Hypoxia in which there is complete absence of oxygen supply is referred to as anoxia.
Survival rate is a part of survival analysis.It is the proportion of people in a study or treatment group still alive at a given period of time after diagnosis. It is a method of describing prognosis in certain disease conditions, and can be used for the assessment of standards of therapy.
The oxygen effect has particular importance in external beam radiation therapy where the killing of tumour cells with photon and electron beams in well oxygenated regions can be up to three times greater than in a poorly vasculated portion of the tumour.
The most common symptoms are dyspnea and hypoxia, usually accompanied by visual changes, headaches, dizziness, confusion, somnolence, and coma. Prompt treatment is required since, if left untreated, it has a very high mortality rate. Treatments aim to rapidly reduce white blood cell counts while also treating the underlying disorder.
An SaO 2 (arterial oxygen saturation) value below 90% causes hypoxia (which can also be caused by anemia). Hypoxia due to low SaO 2 is indicated by cyanosis, but oxygen saturation does not directly reflect tissue oxygenation. The affinity of hemoglobin to oxygen may impair or enhance oxygen release at the tissue level.