Updated Evaluation of the Radiological Risks in Mammography Screening

The long term risks of the exposure of the female breast to ionizing radiation in general and in the framework of mammography screening in particular are reviewed. Updated quantitative evaluation of these risks is based on the analysis of the results of several epidemiological studies. Among these studies are those of the Japanese atomic- bomb survivors and of several groups of women who underwent radiotherapy or medical diagnosis procedures involving multiple chest fluoroscopes. the review is based on recruit UNSCEAR, NCRP and other publications. In general the great majority of the epidemiological studies indicate an increased incidence or mortality from breast cancer following irradiation. Some of file findings of these studies are: A linear dose-response function reasonably fits the epidemiological data. There is a latent period of at least 5 years between exposure and the start of risk increase. The results are consistent with a relative risk model. The fatalities of radiation induced breast cancer is similar to that for other breast cancers. The risk is file highest for young women and is substantially reduced with age at exposure. The dose rate has no major effect on Use risk. The NCRP concludes in its recent report related to mammography 12, that the number of excess breast cancer death cases expected in a population of 100,000 women subsequent to an annual screening examination up to the age of 69 is 18 casts if they start Dee annual screenings at age 40 (a total of 30 screenings), 9 cases if they start at age 45, 4 cases if they start at age 50 and 2 cases only if they start at age 55 (a total of 15 screenings). The total mean glandular dose assumed in these calculations is 4 mGy for each examination. These numbers have to be compared to 16,131, 15,591, 14,569 and 13,211 breast cancer cases expected in that population, subsequent to the above ages, respectively, in Dee absence of screening. The conclusion of the NCRP is that: In summary, it is clear that in terms of breast cancer mortality, the risk of radiation induced mortality, even given n series of 30 annual screenings, is offset by even a minimal benefit in reduced breast cancer mortality from screening as low as one percent' Seven epidemiological studies are reviewed in the NCRP report. All of these, but one, resulted in a significant reduction of 9-32 % in the breast cancer death rate in the screened population (as compared to the non screened population)