Solid Cancer Incidence in the Techa River Incidence Cohort: 1956–2007

Abstract

Previously reported studies of the Techa River Cohort have established associations between radiation dose and the occurrence of solid cancers and leukemia (non-CLL) that appear to be linear in dose response. These analyses include 17,435 cohort members alive and not known to have had cancer prior to January 1, 1956 who lived in areas near the river or Chelyabinsk City at some time between 1956 and the end of 2007, utilized individualized dose estimates computed using the Techa River Dosimetry System 2009 and included five more years of follow-up. The median and mean dose estimates based on these doses are consistently higher than those based on earlier Techa River Dosimetry System 2000 dose estimates. This article includes new site-specific cancer risk estimates and risk estimates adjusted for available information on smoking. There is a statistically significant (P = 0.02) linear trend in the smoking-adjusted all-solid cancer incidence risks with an excess relative risk (ERR) after exposure to 100 mGy of 0.077 with a 95% confidence interval of 0.013-0.15. Examination of site-specific risks revealed statistically significant radiation dose effects only for cancers of the esophagus and uterus with an ERR per 100 mGy estimates in excess of 0.10. Esophageal cancer risk estimates were modified by ethnicity and sex, but not smoking. While the solid cancer rates are attenuated when esophageal cancer is removed (ERR = 0.063 per 100 mGy), a dose-response relationship is present and it remains likely that radiation exposure has increased the risks for most solid cancers in the cohort despite the lack of power to detect statistically significant risks for specific sites.

Breast cancer risk and protracted low-to-moderate dose occupational radiation exposure in the US Radiologic Technologists Cohort, 1983–2008

“…The difference in the ERRs for Japanese and western women appeared to be largely due to marked differences in the baseline rates in Japan from those in western countries. The latest incidence ERR estimate in the cohort of Russian women who received chronic low-dose-rate environmental exposures (Davis et al , 2015) is only slightly higher than that seen in this study, whereas the breast cancer mortality ERR in the Mayak plutonium production workers (Sokolnikov et al , 2015) was somewhat lower than our USRT estimate.…”

“…The estimate corresponds to the ERR at attained age 50 years.dFrom Davis et al (2015).eFrom Sokolnikov et al (2015).…”

“…Exposure–response trends for breast cancer have been reported for women who underwent multiple diagnostic x-rays during childhood and adolescence to assess spinal curvature from scoliosis (Ronckers et al , 2008) and for tuberculosis patients with repeated fluoroscopic examinations (Howe and McLaughlin, 1996; Little and Boice, 1999). A cohort study of Russians (Eidemuller et al , 2008; Ostroumova et al , 2008; Davis et al , 2015) with low-dose-rate environmental exposures found indications of a dose–response association. Most nuclear worker studies are comprised solely of men; however, a study in the United Kingdom that included women found no evidence of an association between radiation dose and breast cancer rates (Muirhead et al , 2009).…”

Low dose radiation risks for women surviving the a-bombs in Japan: generalized additive model

“…Davis [16] studied solid cancer incidence in the Techa River cohort, and found significant effects only for the oesophagus and uterus, using a linear model without interactions. Women constitute 57% of the cohort and age of entry begins at 0.…”

“…Some cancer studies find non-linear responses to radiation [5–8] and there are some significant results at low doses [9–16]. Low dose radiation risk was reviewed in 2003 [17] and remains a focus of research [18].…”