A report on radiation-induced gliomas

Article Abstract:

While radiotherapy is a valuable weapon in the treatment of tumors, the sword has two edges; radiation can induce tumors as well as destroy them. The authors present the cases of three individuals who developed brain tumors after receiving radiotherapy to the head. In addition, the authors tabulate observations on 76 cases of radiotherapy-induced tumors gleaned from the medical literature. For a tumor to be attributed to radiotherapy, it must be a different type than that originally treated tumor and must arise in the region of the body that was exposed to radiation. A sufficient period must elapse after the radiation treatment for the new tumor to be considered an adverse effect of the treatment. Furthermore, patient characteristics that might lead to the independent development of second tumors, such a neurofibromatosis, must be ruled out. The three cases presented here meet these criteria. In two cases, the treatment was for childhood acute lymphoblastic leukemia (ALL); in third case, the patient had been treated with radiation for a fungal infection of the scalp. All three patients developed glioblastoma multiforme, which is a high-grade astrocytoma. These malignant tumors were diagnosed 6, 11, and 26 years after the initial radiation treatment. In their review of the medical literature, however, the authors found that the brain is the most common site of a second tumor after ALL, and that in each published case, except two, the tumor appearing after radiation treatment was a glioma. Furthermore, families with a predisposition to cancer have been identified in which both ALL and gliomas have occurred. Therefore, gliomas and ALL may share common underlying genetic causes and the contribution of the radiation may not represent the entire picture. Clearly, it is important for oncologists to publish the cases of apparent radiation-induced tumors so that more may be learned about the mechanisms of carcinogenesis in these cases. (Consumer Summary produced by Reliance Medical Information, Inc.)

Gliomas, Astrocytoma, Astrocytomas

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Phase II randomized clinical trial of LC9018 concurrently used with radiation in the treatment of carcinoma of the uterine cervix: its effect on tumor reduction and histology

Article Abstract:

Biological response modifiers (BRMs) are a class of compounds which stimulate the immune system in complex ways that are not entirely understood. Some BRMs are synthetic, and some are derived from bacteria. One particular BRM, called LC9018, is derived from the bacteria Lactobacillus casei, strain YIT 9018. This BRM has antitumor effects in mice; it presumably stimulates a successful immune response against transplanted tumors. Similar effects may help patients undergoing radiotherapy for cancer of the cervix. Since suppression of the immune system is an unavoidable side effect of radiotherapy, BRMs may be of value in the recovery process. To determine if this is indeed the case, 49 patients with cervical cancer were randomly assigned to receive either radiotherapy alone, or radiotherapy with LC9018. The administration of the BRM began two weeks before radiotherapy and continued, one or twice a week, for up to four weeks after radiotherapy. Each patient's status was assessed by survival, biopsy of the tumor, laboratory values of immunological function, and BRM side effects. Side effects observed with LC9018 included fever, tenderness, and, in 20 percent of the cases, formation of an abscess at the site of injection. Tests of immune function did not reveal any significant differences between the groups, but blood counts in the treated patients showed less leukocytopenia, or reduction in number of white blood cells. Histological examination of the biopsies revealed a greater effect of the combination treatment than of radiotherapy alone. This effect was mirrored in the survival data of the patients; the rate of survival was higher in the group receiving radiotherapy and BRM. Unfortunately more testing on greater numbers of patients will be needed to determine if the effect of LC9018 is significant, and whether it is warranted as a useful adjunct to radiotherapy. (Consumer Summary produced by Reliance Medical Information, Inc.)

Health aspects, Evaluation, Adjuvant chemotherapy, Biological response modifiers

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Second cancer after radiation therapy for cancer of the uterine cervix

Article Abstract:

It is well recognized that radiation can induce tumors, even at doses lower than those normally given as a part of radiotherapeutic treatment. Studies of workers exposed to radiation and other individuals have shown that doses as low as 1 to 10 Gy can increase the incidence of tumors (a Gy, or Gary, is one Joule of energy absorbed per kilogram of tissue). The radiation exposure used in cancer treatment is much higher, often around 60 Gy. Although it is agreed that radiotherapy causes some risk, there is great controversy over exactly how high this risk actually is. It is certain, however, that as survival rates from cancer continue to improve, greater numbers of individuals will develop second primary cancers after radiotherapy. To estimate the magnitude of the risk, the cases 11,855 women treated for cancer of the cervix were reviewed. Of these, 1,969 received both radiation and surgery, 5,725 received only radiotherapy, and 4,161 were treated with surgery only. Overall, there were no significant differences between the groups when all cancers were considered. However, radiation to the pelvic area does not affect all organs, and when only leukemia and cancer of the bladder and rectum were considered, a significant association emerged. The risk of developing rectal cancer at about 15 years after radiotherapy is estimated to be about five times that of unexposed individuals. It should be kept in mind, however, that this risk represents about two cases in 1,000 successfully treated patients, in contrast with an expected 0.4 cases among untreated subjects. The study demonstrates that organs within the field exposed during radiotherapy experience a small, but statistically significant, increased risk for second primary cancers. (Consumer Summary produced by Reliance Medical Information, Inc.)

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