WHO Grade 1 — pilocytic astrocytoma - accounts for 5% of all reported brain tumors, with a median age at diagnosis of 12 years. This brain tumor is primarily pediatric, although it is also found in adults.
WHO Grade 2 — diffuse astrocytoma
WHO Grade 3 — anaplastic (malignant) astrocytoma - accounts for 7% of all primary brain tumors, with the median age at diagnosis of 51 years of age.
WHO Grade 4 — glioblastoma multiforme (most common) - accounts for 45% of all reported brain tumors, with the median age at diagnosis of 64 years of age.

In addition to these four tumor grades, astrocytomas may combine with oligodendrocytes to produce oligoastrocytoma. Unique astrocytoma variants have also been known to exist.

Symptoms

Although there is variation in initial presentation, in many cases, the first symptom of an astrocytoma is the onset of seizure activity or severe headache. Presentation will vary depending upon the astrocytoma grade, the location of the tumor, among other factors. A Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) scan is necessary to characterize the anatomy of this tumor (size, location, heter/homogeneity). However, final diagnosis of this tumor, like most tumors, relies on histopathologic examination (biopsy examination).

Treatment

A surgeon will typically remove as much of the tumor as he or she can without damaging other critical, healthy brain structures. Often, surgery is followed up by chemotherapy, radiation, or a mix of both. Therapy may be more or less aggressive, depending upon the tumor behavior and patient condition.

Astrocytomas often reappear - the reoccurrence of the tumor are often visible on MRI. The recurrent tumors are then treated similarly as the initial tumor, with sometimes more aggressive chemo or radiation therapy.

There is great life expectancy variation between different subsets of brain tumor. Age and initial diagnosis are often related to survival time.

The prognosis is worst for Grade 4 gliomas, with an average survival time of 14-18 months. Overall, the five year survival rate is 5%.

Read more at Wikipedia.org

• [List your site here Free!]

Do radiofrequency energy fields cause cancer?
From Townsend Letter for Doctors and Patients, 12/1/05 by Ralph W. Moss

Do devices such as cell or mobile phones, which emit radiofrequency electromagnetic fields (RFEMF), cause cancer? According to the American Cancer Society (ACS), this is just another widespread "cancer myth" that is befuddling the minds of the American public. A recent ACS "cancer literacy" poll found that 30% of the general public agrees with the proposition that electronic devices, like cell phones, can cause cancer in people who usethem.

[ILLUSTRATION OMITTED]

Ted Gansler, MD, MBA, Director of Medical Content, American Cancer Society, blames the persistence of this belief on litigious lawyers and the sensationalist media. "Alarming front-page coverage," he says, is primarily to blame. The reality, says Dr. Gansler, is that although "a few studies have suggested a link with certain rare types of brain tumors, the consensus among well-designed population studies is that there is no consistent association between cell phone use and brain cancer" (Gansler 2005).

[ILLUSTRATION OMITTED]

"What has been proven," Dr. Gansler adds, "is that using a cell phone while driving increases the risk of having a car accident. So, keeping your hands free and your eyes on the road is a more significant issue for people who use cell phones" (Gansler 2005b)--as if one potential danger canceled out the other! Furthermore, according to Dr. Gansler, "considerable research has also found no clear association between any other electronic consumer products and cancer."

Dr. Gansler points out that while ionizing radiation such as gamma rays and X-rays can increase cancer risk by causing changes to DNA in cells of the body, low frequency, non-ionizing radiation [such as that emitted by cell phones, ed.] does not cause these DNA changes.

This statement, as far as it goes, is true. However, direct damage to the DNA is not the only way in which harm could be done. Dr. Gansler ignores the possibility that exposure to radiofrequency energy might bring about damage indirectly, through subtle physiological effects on cellular functions. It has been established, for example, that radiofrequency electromagnetic fields can induce a wide variety of physiological changes in cell membranes, signaling pathways, cell growth cycle regulation, and other metabolic processes within the cell.

It has also been suggested that radiofrequency electromagnetic fields may cause 'epigenetic' changes, minute alterations in gene expression, which are brought about by environmental influences. Such alterations in the settings of individual genes can have far-reaching results--as, for example, when a protective gene is deactivated, or a dormant gene switched on. Epigenetic changes, in other words, even though they do not involve direct damage to the DNA, can cause radical alterations in gene expression and cellular functions that can last a lifetime, and that may result in a significantly increased risk of an individual developing cancer and other diseases.

Effects on Melatonin

Furthermore, radiofrequency electromagnetic field exposure may possibly exert a disruptive effect on the body's hormonal systems, with wide-ranging consequences. As researchers at the Fred Hutchinson Cancer Research Center in Seattle have shown, RFEMF is capable of suppressing pineal gland production of the hormone, melatonin. Melatonin may exert a protective effect against cancer, and depressed melatonin levels may in turn predispose towards the development of cancer (Davis 2001).

Other subtle changes in metabolic norms may also be induced by radiofrequency emissions. In the summer of 2005, Turkish scientists at Suleyman Demirel University published a paper showing that exposure to 900 MHz electrical fields (the kind typically emitted by cellular telephones) suppresses production of TSH (thyroid stimulating hormone) and thyroid hormones in rats (Koyu 2005).

They have also shown that long-term RFEMF exposure can lead to chronically increased levels of free radicals, which, coupled with a concomitant decrease in key antioxidant systems in the brain, can lead to a heightened risk of brain cancer. Interestingly, these researchers found that the increased risk of brain cancer could be substantially offset by administration of the dietary supplement, Ginkgo biloba (Ilhan 2004).

A weak but consistent association between exposure to RFEMF and the development of childhood leukemia has been demonstrated. In 1999, the US National Institute of Environmental Health Sciences (NIEHS) concluded that although the evidence was not strong, there were still reasons for caution. The NIEHS rationale, according to its own website, was that "no individual epidemiological study provided convincing evidence linking magnetic field exposure with childhood leukemia, but the overall pattern of results for some methods of measuring exposure suggested a weak association between increasing exposure to EMF and increasing risk of childhood leukemia. The small number of cases in these studies made it impossible to firmly demonstrate this association. However, the fact that similar results had been observed in studies of different populations using a variety of study designs supported this observation." Clearly therefore, even though the association between RFEMF and disease is still very much under investigation, there are definite grounds for concern.

What the Science Shows

Many scientists dismiss the possibility that RFEMFs can cause cancer. But a minority disagrees. Briefly, here are just three of the current and recent studies that have indicated a link between radiofrequency electromagnetic fields and malignancy.

In the eyes of some researchers, in fact, "there is a growing amount of evidence about the harmful effects of EMFs [electromagnetic fields, ed.] on the human body, the most dangerous of which is the possible carcinogenic effect." So wrote Israeli scientists in reviewing the overall field in the spring of 2005 (Beniashvili 2005).

Drs. Leeka I. Kheifets and C. Chantal Matkin, of the Electric Power Research Institute (EPRI) in Palo Alto, California agree with many others that "most of the epidemiologic data do not provide strong support for an association between EMF and breast cancer." However they also state that because of the limited statistical power and the possibility of bias in much of the existing data, "it is not possible to rule out a relationship between EMF and breast cancer" (Kheifets 1999). Significantly, EPRI is generally a pro-industry group, which on the whole would be less likely than more independent scientists to warn of the potential risks of EMF exposure.

There are a few disturbing trends in some of the data. For example, in a meta-analysis performed at the University of Cologne, Germany, Prof. Thomas C. Erren found a 12% increased risk of cancer in women and a 37% increase in men that seemed attributable to EMF exposure. Yet, like most scientists in the field, he adds a note of caution, noting "probable misclassification of exposure and the possible misclassification of the disease itself." (Erren 2001)

Scandinavian researchers have identified an increased risk for acoustic neuroma in cell phone users, and a slightly increased risk of malignant brain tumors such as astrocytoma and meningioma on the same side of the brain as the cell phone was habitually held. However, the authors of this latter study have acknowledged some methodological concerns, and further investigations are planned in order to determine whether such an association can be definitively established with statistical significance (Hardell 2004 and 2005).

Most recently, Djemal Beniashvili and other scientists at the Edith Wolfson Medical Center, Holon, Israel postulated a link between exposure to power frequency fields and breast cancer in elderly women. They made an extensive study of medical records extending over a period of 26 years, involving the analysis of over 200,000 biopsy and surgery samples. They then compared the breast cancer rates in elderly women from an earlier period (1978-1990) to a more recent period (1991-2003), which has been characterized by a much more extensive use of personal computers (more than 3 hours a day), mobile/cell telephones, television sets, air conditioners and other household electrical appliances.

Among the elderly women who developed breast cancer in the first time frame, 19.5% were regularly exposed to power frequency fields. But in the more modern period 51.1% were so exposed, mainly through the use of personal computers. The authors conclude: "There was a statistically significant influence of EMF [electromagnetic fields, ed.] on the formation of all observed epithelial mammary tumors in Group II." This represented a more than two-fold increase, which was considered highly significant (Beniashvili 2005).

In my opinion, it is inappropriate for the ACS to deride the misgivings of the public on the question of radiofrequency electromagnetic fields and their possible association with cancer. Researchers who have raised doubts about the safety of RFEMFs are neither avaricious lawyers nor sensation-seeking journalists, but serious scientists, trying to do an important job in a rational, dispassionate way.

Incidentally, I do own and sometimes use a cell phone, but limit my exposure to its electromagnetic fields. I generally try to use it in speakerphone mode and limit the length of conversations as much as possible. And I take supplemental antioxidants with the intention of reducing free radical damage.

In this, as in other matters, I think the Precautionary Principle applies. If the consequences of an action concerning the use of technology are unknown, but are possibly highly negative, then it is better to limit exposure rather than risk the uncertain, but possibly very negative, consequences.

By attaching derogatory labels to those who are on the opposite side of the debate from themselves, the researchers at ACS will no doubt please the $112 billion cell phone industry. But this does not advance public understanding. It merely stigmatizes as irrational all those who oppose unrestricted technological change and thereby hampers a necessary scientific and public dialogue.

Bibliography

Ahlbom A, Day N, Feychting M et al. A pooled analysis of magnetic fields and childhood leukemia. Br J Cancer. 2000;83:692-8

Beniashvili D, Avinoach'm I, Baasov D, et al. The role of household electromagnetic fields in the development of mammary tumors in women: clinical case-record observations. Med Sci Monit. 2005;11:CR10-3.

Davis S, Kaune WT, Mirick DK, et al. Residential magnetic fields, light-at-night, and nocturnal urinary 6-sulfatoxymelatonin concentration in women. Am J Epidemiol. 2001;154:591-600.

Erren TC. A meta-analysis of epidemiological studies of electric and magnetic fields and breast cancer in women and men. Bioelectromagnetics, 2001;5:105-19.

Food and Drug Administration (FDA). What biological effects can be caused by RF energy? Last updated April 3, 2002. Retrieved July 30, 2005 from: http://www.fda.gov/cellphones/rf-energy.html#2

Gansler T, Henley SJ, Stein K, et al. Sociodemographic determinants of cancer treatment health literacy. Cancer. 2005;104:653-60.

Gansler, T. Do cell phones cause cancer? American Cancer Society website, 2005b. Retrieved from: http://www.cancer.org/docroot/PED/content/PED_11_1_Do_Cell_Phones_Cause_Cancer.asp

Garfield, Larry. Mobile phone usage doubles since 2000, but growth to slow. Infosync World News Centre, Dec. 15, 2004. Retrieved from: http://www.infosyncworld.com/news/n/5636.html

Greenland S, Sheppard AR, Kaune WT, et al. A pooled analysis of magnetic fields, wire codes, and childhood leukemia. Childhood Leukemia-EMF Study Group. Epidemiology. 2000;11:624-34

Hardell L, Mild KH, Carlberg M, et al. Cellular and cordless telephone use and the association with brain tumors in different age groups. Arch Environ Health. 2004;59(3):132-7

Hardell L, Carlberg M, Mild KH. Case-control study of the association between the use of cellular and cordless telephones and malignant brain tumors diagnosed during 2000-2003. Environ Res. 2005 Jul 12

Ilhan A, Gurel A, Arcutcu F, et al. Ginkgo biloba prevents mobile phone-induced oxidative stress in rat brain. Clin Chim Acta. 2004;340:153-62.

Kheifets LI, Matkin CC. Industrialization, electromagnetic fields and breast cancer risk. Environ Health Perspect. 1999;107:145:154.

Koyu A, Cesur G, Ozguner F, et al. Effects of 900 MHz electromagnetic field on TSH and thyroid hormones in rats. Toxicol Lett. 2005;157:257-62.

McCurdy AL, Wijnberg L, Loomis D, et al. Exposure to extremely low frequency magnetic fields among working women and homemakers. Ann Occup Hyg. 2001;45:643-50.

Moulder JE, Foster KR, Erdreich LS, et al. Mobile phones, mobile phone base stations and cancer: a review. Int J Radiat Biol. 2005;8:189-203.

Scott A, Dana KM, Stevens RY: Residential magnetic fields and risk of breast cancer. Am J Epidemiol, 2002;155:446-54.

Information on EPRI retrieved July 30, 2005 from: http://www.cspinet.org/integrity/nonprofits/electric_power_research_institute.html

Information on fluoroscopes retrieved July 31, 2005 from: http://www.straightdope.com/classics/a2_414a.html

Information on American Medical Association and tobacco retrieved July 31, 2005 from: http://www.thoracic.org/chapters/california_adobe/TobaccoHx.pd

(NIEHS website: http://www.niehs.nih.gov/emfrapid/booklet/results.htm)

by Ralph W. Moss, PhD, Director, The Moss Reports

800-980-1234 * www.cancerdecisions.com

Return to Astrocytoma

Home

Contact

Resources

Exchange Links

ebay