• Asian Pacific Journal of Cancer Prevention
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• 제17권6호
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• pp.2979-2982
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• 2016

Background: High dose ionizing radiation can induce ovarian cancer, but the effect of low dose radiation on the development of ovarian cancer has not been extensively studied. We evaluated the effect of low dose radiation and total background radiation, and the radiation delivered to the ovaries during the treatment of rectosigmoid cancer and breast cancer on ovarian cancer incidence. Materials and Methods: Background radiation measurements are from Assessment of Variations in Radiation Exposure in the United States, 2011. Ovarian cancer incidence data are from the Centers for Disease Control and Prevention. Standardized incidence ratios (SIR) of ovarian cancer following breast cancer and rectosigmoid cancer are from Surveillance, Epidemiology, and End Results (SEER) data. Obesity data by US state are from the Centers for Disease Control and Prevention. Mean ages of US state populations are from the United States Census Bureau. Results: We calculated standardized incidence ratios (SIR) from Surveillance, Epidemiology, and End Results (SEER) data, which reveal that in 194,042 cases of breast cancer treated with beam radiation, there were 796 cases of ovarian cancer by 120+ months of treatment (0.41%); in 283, 875 cases of breast cancer not treated with radiation, there were 1,531 cases of ovarian cancer by 120+ months (0.54%). The difference in ovarian cancer incidence in the two groups was significant (p < 0.001, two tailed Fisher exact test). The small dose of scattered ovarian radiation (about 3.09 cGy) from beam radiation to the breast appears to have reduced the risk of ovarian cancer by 24%. In 13,099 cases of rectal or rectosigmoid junction cancer treated with beam radiation in the SEER data, there were 20 cases of ovarian cancer by 120+ months of treatment (0.15%). In 33,305 cases of rectal or rectosigmoid junction cancer not treated with radiation, there were 91 cases of ovarian cancer by 120+ months (0.27%). The difference in ovarian cancer incidence in the two groups was significant (p = 0.017, two tailed Fisher exact test). In other words, the beam radiation to rectum and rectosigmoid that also reached the ovaries reduced the risk of ovarian cancer by 44%. In addition, there was a significant inverse relationship between ovarian cancer in white women and radon background radiation (r = - 0.465. p = 0.002) and total background radiation (r = -0.456, p = 0.002). Because increasing age and obesity are risk factors for ovarian cancer, multivariate linear regression was performed. The inverse relationship between ovarian cancer incidence and radon background was significant (${\beta}=-0.463$, p = 0.002) but unrelated to age (${\beta}=-0.080$, p = 0.570) or obesity (${\beta}=-0.180$, p = 0.208). Conclusions: The reduction of ovarian cancer risk following low dose radiation may be the result of radiation hormesis. Hormesis is a favorable biological response to low toxin exposure. A pollutant or toxin demonstrating hormesis has the opposite effect in small doses as in large doses. In the case of radiation, large doses are carcinogenic. However, lower overall cancer rates are found in U.S. states with high impact radiation. Moreover, there is reduced lung cancer incidence in high radiation background US states where nuclear weapons testing was done. Women at increased risk of ovarian cancer have two choices. They may be closely followed (surveillance) or undergo immediate prophylactic bilateral salpingo-oophorectomy. However, the efficacy of surveillance is questionable. Bilateral salpingo-oophorectomy is considered preferable, although it carries the risk of surgical complications. The data analysis above suggests that low-dose pelvic irradiation might be a good third choice to reduce ovarian cancer risk. Further studies would be worthwhile to establish the lowest optimum radiation dose.

• 인터넷정보학회논문지
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• 제22권1호
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• pp.41-50
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• 2021

사이버 킬체인 (Cyber Kill Chain)은 기존의 군사적 용어인 킬체인 (Kill Chain)에서 유래한다. 킬체인은 "파괴를 요구하는 군사 표적을 탐지하는 것에서 파괴하는 것까지의 연속적이고 순환적인 처리 과정 또는 그것을 몇 개의 구분된 행위로 나눈 것"을 의미한다. 킬체인은 핵무기나 미사일과 같이 위치가 변화하고 위험성이 커서 즉각적인 대응을 요구하는 시한성 긴급 표적을 효과적으로 다루기 위해 기존의 작전절차를 발전시켰으며, 방어자가 파괴를 필요로 하는 핵무기나 미사일이 타격점에 도달하기까지의 여러 과정 중 한 단계라도 제 기능을 발휘하지 못하게 하여 공격자가 의도한 목적을 달성하지 못하도록 무력화하는 군사적 개념에서 시작되었다고 볼 수 있다. 이러한 사이버 킬체인의 기본 개념은 사이버 공격자가 수행하는 공격은 각 단계로 구성되어 있으며, 사이버 공격자는 각 단계가 성공적으로 수행되어야 공격 목표를 달성할 수 있으며, 이를 방어 관점에서 보았을 때 각 단계에서 세부적으로 대응 절차를 마련하여 대응하면 공격의 체인 (chain)이 끊어지므로 공격자의 공격을 무력화하거나 지연시킬 수 있다고 본다. 또한 공격 관점에서 보았을 때 각 단계에서 구체적인 대응 절차를 마련하면 공격의 체인이 성공하여 공격대상을 무력화시킬수 있다. 사이버 지휘통제체계는 방어와 공격에 모두 적용되는 체계로 방어시 적의 킬체인을 무력화하기 위한 방어 대응 방안을 제시하여야 하며 공격시에는 적을 무력화하기 위한 각 단계별 구체적인 절차를 제시하여야 한다. 따라서 본 논문은 사이버 지휘통제체계의 방어 및 공격 관점의 사이버 킬체인 모델을 제안하였으며, 또한 방어 측면의 사이버 지휘통제제계의 위협 분류/분석/예측 프레임워크를 제시하였다.