Radiation treatment of cerebral arteriovenous malformations

Article Abstract:

An article in the July 12, 1990 issue of The New England Journal of Medicine reports the success of helium-ion radiation in treating small cerebral arteriovenous malformations (abnormal connections between arteries and veins in the brain with potential for hemorrhage, seizures, or other consequences). Ninety-seven percent of small malformations (less than 3.7 centimeters in diameter) were completely obliterated after treatment with the helium beam. However, the method is risky (9 percent of the patients suffered permanent neurologic impairment), and beneficial effects may take years to be realized: after one year, 39 percent of the lesions were obliterated; after two years, 84 percent were destroyed. Patients appear to be at risk for bleeding from these malformations as long as even a small portion remains intact. Unfortunately, the authors did not indicate how many patient-years of follow-up they performed, information that is critical in evaluating whether obliteration prevents hemorrhage. Two other methods of highly focused radiation, the gamma knife (using a cobalt source) and the linear accelerator, are discussed. Results from some published studies are reported, but variations in lesion size, degree of neurologic complications, and radiation dose levels, make comparisons between studies difficult. What are the alternatives to radiation treatment? If no treatment is instituted, the risk of rebleeding is approximately 6 percent the first year, then 3 to 4 percent in subsequent years. When bleeding occurs, it carries a 30 percent risk of damage, and a 10 percent risk of death; these figures are unacceptably high, especially for younger patients. Surgical techniques have improved in recent years and, in general, operated patients have lower morbidity, mortality, and essentially no risk of delayed hemorrhage. Overall, surgery is the preferred approach, except for small lesions in deep, important brain areas that are inaccessible to surgery. Large lesions in critical areas remain difficult to treat. Finally, little is known about possible long-term carcinogenic effects of focused radiation therapy to the brain, because such effects may take many years to develop. Careful screening of patients with cerebral arteriovenous malformations is essential to determine whether radiation treatment is really a wise therapeutic option. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, editorial

---

Stereotactic heavy-charged-particle Bragg-peak radiation for intracranial arteriovenous malformations

Article Abstract:

Arteriovenous malformations of the brain are abnormal anatomical arrangements between veins and arteries which can cause illness or death. If untreated, they can cause hemorrhage, seizures, neurologic deficits, or incurable headaches. While many malformations can be surgically corrected, many cannot and are treated with radiation delivered according to stereotactic coordinates (precisely localized according to a coordinate system). Radiation directed at an arteriovenous malformation can cause its blood vessels to develop thicker walls and can induce obliteration of the malformation by causing a clot to form. A method using heavy-charged-particles (helium-ion beam) was evaluated for treating malformations in 86 patients (average age, 33), all of whom had serious symptoms and could not undergo surgery. The patients were followed-up for an average of 38 months. Results showed lessening of seizure severity in 63 percent of the patients; reduction of headaches in 68 percent; and fewer neurologic deficits in 27 percent. The outcome was considered excellent in 58 percent, and good in 36 percent of the subjects. Follow-up with angiography (X-ray of blood vessels filled with a substance opaque to the beam) in 71 patients showed that lesions were completely obliterated in 62 percent of the patients, partially obliterated in 28 percent, and unchanged in 10 percent. Smaller lesions were easier to destroy than larger ones. Bleeding occurred in 10 patients, two of whom died. Seven patients had minor complications after the procedure, and 10 had major complications. Of these, there were 11 partial recoveries and seven full recoveries. However, almost all complications occurred among patients treated earlier in the study at higher radiation doses. Overall, the malformation obliteration rate was 29 percent after one year, 70 percent after two years, and 92 percent after three years. The time required for this effect to be fully realized is a drawback to stereotactic radiation, and a potentially dangerous one, since malformations can bleed as long as they are present. Also, the neurologic status of these patients grew worse, but these results must be compared with the probable course of untreated malformations. Between 40 and 80 percent of such patients die or become severely disabled. (Consumer Summary produced by Reliance Medical Information, Inc.)

Methods

---

A founder mutation as a cause of cerebral cavernous malformation in Hispanic Americans

Article Abstract:

Hispanic/Mexican Americans with cerebral cavernous malformation probably share the same inherited mutation on chromosome 7. More Mexican Americans than members of other ethnic groups have cerebral cavernous malformation, a brain disease characterized by headaches, seizures, and brain hemorrhaging. Researchers used polymerase chain reaction to study the genetic make-up of 57 patients with cavernous malformation. Patients were 2 to 59 years old, with varying degrees of symptomatic disease. Unique alleles in the large segment of chromosome 7q linked affected family members but was absent among healthy relatives. These genetic markers were evident even in younger patients without symptoms and in so-called sporadic cases. Since the probability of sharing these mutations by chance alone is extremely low, virtually all cases are are thought to be linked to a founder mutation, caused by common ancestor.

Research, Genetic aspects, Genetic markers, Mexican Americans, Cerebrovascular disease, Cerebrovascular disorders, Human chromosome abnormalities

Similar abstracts:

• Abstracts: Response to treatment of congenital adrenal hyperplasia in infancy. Dexamethasone treatment for congenital adrenal hyperplasia
• Abstracts: Diagnosis and treatment of orofacial herpes zoster: report of cases. The cracked tooth syndrome: an elusive diagnosis
• Abstracts: Intestinal infarction after intravenous cocaine administration. Potentiation of cocaine-induced coronary vasoconstriction by beta-adrenergic blockade
• Abstracts: Pregnancy-induced hypertension and acute fatty liver of pregnancy: atypical presentations. Urinary tract dilatation in pregnancy
• Abstracts: Risks associated with an elevated maternal serum alpha-fetoprotein level. Maternal serum alpha-fetoprotein levels in pregnancies complicated by diabetes: implications for screening programs

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.