Department of Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan.
Department of Statistics, Radiation Effects Research Foundation, Hiroshima, Japan.
Int J Cancer. 2020 Feb 1;146(3):635-645. doi: 10.1002/ijc.32275. Epub 2019 Apr 3.
Radiation effects on colorectal cancer rates, adjusted for smoking, alcohol intake and frequency of meat consumption and body mass index (BMI) by anatomical subsite (proximal colon, distal colon and rectum) were examined in a cohort of 105,444 atomic bomb survivors. Poisson regression methods were used to describe radiation-associated excess relative risks (ERR) and excess absolute rates (EAR) for the 1958-2009 period. There were 2,960 first primary colorectal cancers including 894 proximal, 871 distal and 1,046 rectal cancers. Smoking, alcohol intake and BMI were associated with subsite-specific cancer background rates. Significant linear dose-responses were found for total colon (sex-averaged ERR/Gy for 70 years old exposed at age 30 = 0.63, 95% confidence interval [CI]: 0.34; 0.98), proximal [ERR = 0.80, 95% CI: 0.32; 1.44] and distal colon cancers [ERR = 0.50, 95% CI: 0.04; 0.97], but not for rectal cancer [ERR = 0.023, 95% CI: -0.081; 0.13]. The ERRs for proximal and distal colon cancers were not significantly different (p = 0.41). The ERR decreased with attained age for total colon, but not for proximal colon cancer, and with calendar year for distal colon cancer. The ERRs and EARs did not vary by age at exposure, except for decreasing trend in EAR for proximal colon cancer. In conclusion, ionizing radiation is associated with increased risk of proximal and distal colon cancers. The ERR for proximal cancer persists over time, but that for distal colon cancer decreases. There continues to be no indication of radiation effects on rectal cancer incidence in this population.
在一个由 105444 名原子弹幸存者组成的队列中，研究了辐射对结直肠癌发病率的影响，这些发病率经过了吸烟、饮酒、肉类摄入频率和体重指数（BMI）的调整，按解剖部位（近端结肠、远端结肠和直肠）进行了细分。使用泊松回归方法描述了 1958 年至 2009 年期间与辐射相关的超额相对风险（ERR）和超额绝对发病率（EAR）。共有 2960 例首次原发性结直肠癌，包括 894 例近端、871 例远端和 1046 例直肠癌。吸烟、饮酒和 BMI 与特定部位的癌症背景发病率有关。在总结肠（暴露于 30 岁时，70 岁时的雌雄平均 ERR/Gy 为 0.63，95%置信区间[CI]：0.34；0.98）、近端[ERR=0.80，95%CI：0.32；1.44]和远端结肠癌症[ERR=0.50，95%CI：0.04；0.97]中发现了显著的线性剂量反应，但在直肠癌症[ERR=0.023，95%CI：-0.081；0.13]中未发现这种反应。近端和远端结肠癌症的 ERR 没有显著差异（p=0.41）。对于总结肠，ERR 随获得年龄的增加而降低，但对于近端结肠癌症，ERR 随日历年份的增加而降低。除了近端结肠癌症的 EAR 呈下降趋势外，ERR 和 EAR 不受暴露年龄的影响。总之，电离辐射与近端和远端结肠癌风险增加有关。近端结肠癌的 ERR 随着时间的推移而持续，但远端结肠癌的 ERR 则下降。在该人群中，仍然没有直肠癌发病率受到辐射影响的迹象。
