STUDIES OF RADIATION-INDUCED CANCER

研究暴露于辐射的人群，以量化癌症风险， 了解致癌机制。 实验室研究 纳入流行病学调查。 工作人员服务于 向政府和国际机构提供咨询的委员会。 最近的研究表明：（1）全身化疗联合 放射治疗增加了接受非放射性治疗的患者患白血病的风险。 霍奇金淋巴瘤;（2）乳腺癌和霍奇金淋巴瘤的放射治疗 疾病会增加患肺癌的风险;吸烟可能会增加这种风险; (3)消化性溃疡的放射治疗会增加胃癌的风险， 手术治疗后进一步增加;（4） 视网膜母细胞瘤有30%的累积风险发展为第二个 癌症40岁;放疗增强这种遗传易感性;（5） 子宫内膜癌的放射治疗引起的白血病比预期的要少 由于细胞杀伤和延长;（6）放射性碘不 增加患白血病或甲状腺癌的风险，这表明， 延长剂量可降低风险;（7）乳腺癌未增加 （8）在职业上暴露于辐射的医疗技术人员中; 在不吸烟的地下矿工中， 高于吸烟者;风险随着暴露时间的延长而降低 （9）氡风险与以下因素有关： 然而，在4个大型系列中无法检测到室内暴露; 风险水平可能太低，无法令人信服地检测;（10）在原子弹中 幸存者，20岁之前接触的乳腺癌风险最大; 早发型乳腺癌的风险非常高， 年龄35岁，表明遗传易感性;（11）辐射引起的 甲状腺癌在20岁以后的暴露是罕见的;（12）定量 对非黑色素瘤皮肤癌和肝癌的风险进行了估计， （13）辐射诱发的肺癌往往是 原子弹幸存者和铀矿工人的小细胞亚型。

Populations exposed to radiation are studied to quantify cancer risks and to understand carcinogenic mechanisms. Laboratory studies are incorporated into epidemiologic investigations. Staff serve on committees advising the government and international agencies. Recent findings indicate that (1) systemic chemotherapy combined with radiotherapy enhances the risk of leukemia in patients treated for non- Hodgkin's lymphoma; (2) radiotherapy for breast cancer and Hodgkin's disease increases the risk of lung cancer; smoking may enhance this risk; (3) radiotherapy for peptic ulcer increases the risk of stomach cancer, which is further increased after surgical treatment; (4) survivors of retinoblastoma are at a 30% cumulative risk for developing a second cancer by age 40; radiotherapy enhances this genetic susceptibility; (5) radiotherapy for endometrial cancer causes fewer leukemias than expected because of cell-killing and protraction; (6) radioactive iodine did not increase the risk of leukemia or thyroid cancer, suggesting that protraction of dose reduces risk; (7) breast cancer was not increased among medical technologists occupationally exposed to radiation; (8) the risk of radon-induced lung cancer among nonsmoking underground miners is greater than among smokers; risk decreases as the exposure duration shortens and with time since exposure; (9) a radon risk associated with indoor exposure, however, could not be detected in 4 large series; the level of risk may be too low to detect convincingly; (10) among A-bomb survivors, breast cancer risk was greatest for exposure before age 20; risk was remarkably high for early-onset breast cancer occurring before age 35, suggesting a genetic susceptibility; (11) radiation-induced thyroid cancer is rare for exposures after age 20; (12) quantitative estimates of risk for non-melanoma skin and liver cancers were made for the first time; (13) radiation-induced lung cancers tend to be of the small-cell subtype in both A-bomb survivors and uranium miners.