Neoplasms from radiation

Retroviruses have been isolated repeatedly from radiation-induced and chemically induced leukemias however, their role, if any, in the induction of these neoplasms remains uncertain at this time (Kaplan, 1984). 

Prostate cancer is a malignant neoplasm that arises from the prostate gland. Prostate cancer has an indolent course localized prostate cancer is curable by surgery or radiation therapy but advanced prostate cancer is not yet curable. 

Fig. 3.1 Dose-incidence curves for different neoplasms in animals exposed to external radiation (A) myeloid leukemia in x-irradiated mice (°) (Upton et al., 1958) (B) mammary gland tumors at 12 months in gamma-irradiated rats (A) (Shellabarger et al., 1969) (C) thymic lymphoma in x-irradiated mice ( ) (Kaplan and Brown, 1952) (D) kidney tumors in x-irradiated rats (o) (Maldague, 1969) (E) skin tumors in alpha-irradiated rats (percentage incidence x 10) ( ) (Bums et al., 1968) (F) skin tumors in electron-irradiated rats (percentage incidence x 10) (A) (Bums et al., 1968) (G) reticulum cell sarcoma in x-irradiated mice (0) (Metalli et al., 1974) (H) lung adenomas in neutron-irradiated mice ( ) (Ullrich et al., 1976) (Modified from UNSCEAR, 1972) (from Upton, 1984).

Leukaemia was the first cancer to be linked with exposure to radiation from the atomic bombings at Hiroshima and Nagasaki, Japan. Excess relative risk for leukaemia was higher than for any other neoplasm in bomb survivors and for people exposed as children. Radiation-related leukaemia started to occur two to three years after the bombing, reached its peak within six to eight years, and has declined steadily since then. For people exposed as adults, the excess risk was lower than that of people exposed as children, but the excess risk appears to have persisted throughout the followup period (LARC, 2000). Small increases in childhood leukaemia may also have occurred in some populations that were exposed to... 

The toxicity of the actinide elements which requires an absolute barrier between the experiment and the experimenter is dictated to only a small extent by external radiation hazards. Plutonium-239 is intensely radioactive, emitting 1.4 X 10 a particles per milligram per minute. However, the alpha radiation from plutonium-239 can easily be shielded by even a thin sheet of paper. It is the consequences of ingestion that make plutonium-239 and the other actinide elements such toxic substances. Plutonium-239, inhaled into the lungs as fine particulate matter, is translocated to the bone, and, over a period of time, may give rise to bone neoplasms (cf. Section 14.10). The biological properties of the actinide elements are discussed in more detail in Sections 14.9 and 14.10. 

The neoplasm usually presents as a large, lobulated and solitary mass with a central fibrous scar that may be calcified (Ichikawa et al. 1999). Microscopically, FLC is characterized by cords of tumor cells sur-roundedbyabundantavascular fibrous tissue. Fibrotic lamellae often form a central scar and multiple septa which radiate from the centre of the lesion. 

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