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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Penetrating ionizing radiation fairly uniformly puts all exposed molecules and cells at approximately equal risk for deleterious consequences. Thus, the original deposition of radiation energy (that is, the dose) is unaltered by metabolic characteristics of cells and tissue, unlike the situation for chemical agents. Intensely ionizing radiations, such as neutrons and alpha particles, are up to ten times more damaging than sparsely ionizing sources such as x-rays or gamma rays for equivalent doses. Furthermore, repair in cells and tissues can ameliorate the consequences of radiation doses delivered at lower rates by up to a factor of ten compared with comparable doses acutely delivered, especially for somatic (carcinogenic) and genetic effects from x- and gamma-irradiation exposure. Studies on irradiated laboratory animals or on people following occupational, medical or accidental exposures point to an average lifetime fatal cancer risk of about 1 x 10(-4) per rem of dose (100 per 10(6) person-rem). Leukemia and lung, breast and thyroid cancer seem more likely than other types of cancer to be produced by radiation. Radiation exposures from natural sources (cosmic rays and terrestrial radioactivity) of about 0.1 rem per year yield a lifetime cancer risk about 0.1 percent of the normally occurring 20 percent risk of cancer death. An increase of about 1 percent per rem in fatal cancer risk, or 200 rem to double the "background" risk rate, is compared with an estimate of about 100 rem to double the genetic risk. Newer data suggest that the risks for low-level radiation are lower than risks estimated from data from high exposures and that the present 5 rem per year limit for workers is adequate.
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PMID:Ionizing radiation and its risks. 676 69

A retrospective cohort study was conducted on the risk of radiation-induced cancer mortality following cardiac catheterization. The study included 4,891 children with congenital heart disease who were assessed by cardiac catheterization during 1946 to 1968 at The Hospital for Sick Children, Toronto. The cohort was matched against the Ontario cancer death file from 1950 to 1975. The average period of follow-up was 13 years and more than 66,000 person-years have been accrued from the cohort. No deaths from breast cancer or thyroid cancer were identified. Five cancer deaths were observed and compared with 4.8 expected deaths based on Ontario cancer death rates. The five cancer deaths resulted from three leukemias, one Wilms' tumor, and one unspecified nervous system tumor. The preliminary findings did not demonstrate a significant leukemia risk arising from diagnostic cardiac catheterizations. Continued follow-up of this cohort is required to evaluate the risk of breast and thyroid cancers which can occur more than 20 years following radiation exposure.
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PMID:Cancer mortality following cardiac catheterization: a preliminary follow-up study on 4,891 irradiated children. 682 26

The paper presents an evaluation of 1.236 cases of different forms of leukemia. Malignant tumors of different localizations were identified in 21 cases (1.7%). Neoplasms were most frequently associated with chronic lymphoid leukemia (4%), followed by osteomyelosclerosis (1.3%), chronic myeloleukemia (1%), polycythemia (0.9%) and acute leukemia (0.44%). A case of chronic myeloleukemia with concomitant myelosarcoma, thyroid cancer, malignant tumor of kidney and cortical adenoma is presented. The role of immunological disorders and cytostatic therapy in the genesis of "secondary" tumor are discussed.
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PMID:[Malignant neoplasms in leukemias]. 694 37

The health risks from low-dose sparsely ionizing (low-LET) radiation have been the subject of continued debate. At present, quantitative estimates of risk are extremely uncertain due to the controversy surrounding both the dosimetry for A-bomb survivor data and the choice of mathematical models for extrapolating risk from high to low doses. Nevertheless, much can be learned about the nature of the health risks by reviewing the epidemiologic literature. We present a summary of diseases which have been associated with low-LET radiation (less than 1000 rad) in at least two independent studies, according to the mean cumulative organ dose at which the disease was observed. At organ doses of less than or equal to 50 rad, the only diseases that have been reported consistently are thyroid cancer, salivary gland tumors, and leukemia. The first two diseases were observed in association with x-ray epilation of the scalp for tinea capitis, a therapy which is no longer employed. On the other hand, leukemia has been observed repeatedly to occur at cumulative doses of greater than or equal to 30 rad low-LET radiation.
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PMID:Identifying the health risks from very low-dose sparsely ionizing radiation. 704 60

Due to the long latency period for solid tumor induction (median 12-13 years), the radiation-induced malignancies now being observed are mostly related to the era of kilovoltage irradiation. Some tumors, such as thyroid cancer, have very low, if any, threshold dose for tumor induction. Sarcomas appear to require higher doses (approximately 100 rads) for induction. Controversy exists as to whether high doses of irradiation are less carcinogenic than lower doses due to greater cell killing at high doses. Acute leukemia has been induced by either irradiation alone or chemotherapy alone. Current intensive therapy protocols using combinations of chemotherapy and radiotherapy, or prolonged chemotherapy, are more leukemogenic, with the 4-year actuarial risk of leukemia in the range 4-17%. Immunosuppression due to various disease states or treatments had been accompanied by malignant tumors, often lymphomas in unusual sites such as the central nervous system. Unusual non-Hodgkin's lymphomas have recently been observed in patients treated for Hodgkin's disease, suggesting that some secondary neoplasms in cancer patients are related to immunosuppression.
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PMID:Adverse effects of cancer therapy. Risk of secondary neoplasms. 709 71

Late somatic effects of ionizing radiation can be divided into non-stochastic effects with relatively high threshold doses (cataract, fertility problems, chronic radiodermatitis, and radiogenic skin cancer) and non-threshold stochastic effects. Theoretical and epidemiologic aspects of radiocarcinogenesis and various clinical types of radiation-induced neoplasms (leukemia, thyroid cancer, breast cancer) and genetic effects are discussed with special reference to radiation protection measures.
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PMID:[Dermatologic roentgen therapy and radiocarcinogenesis]. 709 82

As an extension of the previous finding that radioactivity of 14C-labeled D-amino acids after injection is localized preferentially in the tumor and the pancreas of tumor-bearing animals as compared with the corresponding L-amino acids tested, the results of similar uptake experiments using other tumors araa reported here. The present studies show high radioactivity uptake by human colon cancer, human thyroid cancer, and human leiomyosarcoma transplanted into nude mice, and by solid leukemia L1210 and solid sarcoma 180, but not by Morris hepatoma 7316A or 3'-methyl-4-(dimethylamino)azobenzene-induced rat hepatoma. The results suggest the potential utility of 11C-labeled D-amino acids for the detection of some cancers.
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PMID:High uptake of 14C-labeled D-amino acids by various tumors. 711 46

The therapeutic approach of internally administered radiopharmaceuticals offers the potential to outmode the present approaches of conventional radiation therapy and chemotherapy because of three characteristics: 1. The therapeutic use of radiopharmaceuticals may deliver as much as orders of magnitude larger rad doses than conventional radiation therapy to target tissues, selectively irradiating these tissues internally in one radiation dose. 2. The therapeutic use of radiopharmaceuticals is followed by a lower incidence of leukemia and other cancers. 3. The treatment is comparatively noninvasive and nontraumatic. We can now make this rather strong statement with fairly firm conviction because Na131I has been used since 1946 (33 years) to treat almost a million patients for hyperthyroidism (a) and in approximately 5000 patients for well-differentiated thyroid cancer (b); NaH2PO4(P-32) has been used for 35 years to treat approximately 25,000 patients with polycythemia vera (3-5).
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PMID:New horizons for therapeutic nuclear medicine in 1981. 722 26

Since 1980 the German Registry of Childhood Malignancies has been established. In the framework of the long-term follow-up secondary malignancies are reported continually to the registry. An additional retrospective inquiry to all treating clinicians and principal investigators of clinical trials as well as a link to a previously existing pool of secondary malignancies (1) lead to a completion of the data. At the registry now 329 patients with second malignant neoplasms have been observed. 41.3% of them had been developed the first malignancy before the registry started its work in 1980. The most common primary malignancies are acute lymphoblastic leukaemia (ALL, 28.6%), brain tumours (12.2%), and retinoblastomas (8.8%). Compared to the population of the registry retinoblastomas as a secondary malignancy occur in excess (2.5% vs 8.8%). Most common secondary malignancies are brain tumours (20.1%), acute non-lymphoblastic leukaemia (13.1%), osteosarcomas (10.9%), and thyroid carcinomas (6.1%). Hereby especially for thyroid cancer a remarkable deviation from the frequency in the total population of the registry (0.2%) is observed. In 3% of the patients a secondary malignancy appears within a span of 10 years after the primary malignancy. This is a twentyfold increase compared with the cumulative rate of developing a malignancy in the first 10 years of life. Brain tumours after ALL (8.5%) and after other brain tumours (5.8%) and osteosarcomas after retinoblastomas (4.9%) are the most often reported combinations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Second neoplasms after malignant diseases in childhood]. 756 46

The mortality of all 14,282 workers employed at the Sellafield plant of British Nuclear Fuels between 1947 and 1975 was studied up to the end of 1988 and cancer incidence was examined from 1971 to 1986. This updates a previous report on mortality only up to the end of 1983. Ninety-nine per cent of the workers were traced satisfactorily. Cancer mortality was 4% less than that of England and Wales [standardised mortality ratio (SMR) = 96; 95% confidence interval (CI) = 90,103] and the same as that of Cumbria (SMR = 100: Cl = 94,107). Cancer incidence was 10% less than that of England and Wales [standardised registration ratio (SRR) = 90; Cl = 83.97] and 18% less than that of Northern Region (SRR = 82; Cl = 75.88). Cancer mortality rates were significantly in excess of national rates for cancers of the pleura (nine observed, 2.6 expected; P = 0.001), thyroid (six observed, 1.8 expected; P = 0.01) and ill defined and secondary sites (53 observed, 39.2 expected; P = 0.02). There were significant deficits of cancers of the liver and gall bladder, larynx and lung. Among radiation workers there were significant positive correlations between accumulated radiation dose and mortality from cancers of ill-defined and secondary sites (10 year lag: P = 0.01) and for leukaemia (2 year lag: P = 0.009), but not for cancers of the pleura and thyroid cancer. Previous findings of such associations with multiple myeloma and bladder cancer were less strong. There was a significant excess of incident cases of cancer of the oesophagus (P = 0.01), but this was not associated with accumulated radiation dose. For cancers other than leukaemia, the dose-response risk estimates were below those of the adult atomic bomb survivors, but the 90% confidence interval included risks of zero and of 2-3 times higher. For leukaemia (12 deaths, excluding CLL), under an excess relative risk model, the risk estimate derived for the Sellafield workers was about four times higher than that for the adult atomic bomb survivors with a confidence interval ranging from a half to nearly 20 times that of the atomic bomb survivors. Overall, however, there was no excess of leukaemia among the workers compared with national rates.
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PMID:Cancer mortality and morbidity among workers at the Sellafield plant of British Nuclear Fuels. 798 Oct 83


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