编者按:根据世界卫生组织对超重和肥胖的定义,成人的体重指数(体重除以身高的平方)≥25kg/m²为超重,≥30kg/m²为肥胖。虽然超重与许多健康风险(包括心脏病和糖尿病)相关,但是目前的乳腺癌筛查指南并未予以考虑。
2018年3月15日,美国癌症学会《癌症》发表瑞典卡罗林学院的研究报道,发现对于超重女性,乳腺肿瘤未被检出但是以后迅速变大的风险较大,并且可能需要经常进行钼靶检查。该研究曾于2017年11月20日北美放射学会(RSNA)第104届年会公布。
该研究对2001~2008年被诊断为乳腺浸润癌患者2012例进行随访直至2015年底,分析疾病进展与体重指数和钼靶密度的关系,确定肿瘤未被查出(直至大于2cm为止)的风险因素,并且探讨其对长期预后的影响。2cm为区分癌症I期与II期的指标之一,并且已知与预后密切相关。
结果发现,虽然两个因素(体重指数和钼靶密度)均与被诊断为乳腺癌时的肿瘤大小成正比,但是对于每两年一次常规钼靶检查之间发生的间隔癌,仅体重指数与肿瘤大小相关。此外,对于间隔癌患者,体重指数较高与较低的女性相比,预后较差,而且钼靶密度与疾病进展无显著相关性。
因此,这些结果可能有助于临床医生和患者优化筛查决策。作者建议,当临床医生与患者讨论要不要进行乳腺癌筛查时,对于超重患者,应该考虑“要”,并且应该考虑缩短筛查间隔时间。此外,由于超重女性的肿瘤分子学类型和激素受体表达水平使癌症较难治疗,预后较差的风险可能较大。
不过,该研究在瑞典进行,该国推荐筛查间隔18~24个月,美国预防服务工作组推荐筛查间隔24个月,而美国其他组织建议间隔12个月。而且,瑞典与美国相比,超重女性较少。
Cancer. 2018 Mar 15;124(6):1099.
Overweight women may require more frequent mammograms.
Printz C.
Women with a higher body mass index (BMI) are at greater risk of not being diagnosed with a breast tumor until it becomes large, and may need to undergo mammography screening more frequently, according to a study presented in November 2017 at the annual meeting of the Radiological Society of North America.
Although high BMI is associated with many health risks, including heart disease and diabetes, it is not considered in current breast cancer screening guidelines.
Researchers at the Karolinska Institute in Stockholm, Sweden, sought to identify risk factors for tumors that were not detected until they measured larger than 2 centimeters, and to examine the implications for long-term prognosis. The 2-centimeter size is one of the parameters used to separate stage I and stage II cancers and is known to be strongly associated with prognosis, according to coauthor Fredrik Strand, MD, a radiologist at Karolinska University Hospital.
Investigators studied 2012 cases of invasive breast cancer that appeared from 2001 to 2008, and followed the patients through the end of 2015. They analyzed how disease progression was connected to both BMI and breast density. Both factors were found to be associated with the presence of a large tumor at the time of diagnosis. However, for interval cancers (those detected within 2 years of a normal mammogram), only BMI was associated with having a large tumor.
Moreover, among patients with interval cancers, women with a higher BMI had worse prognoses than those with a lower BMI, whereas breast density bore no significant association with disease progression.
Dr. Strand concludes that the findings may help to inform clinicians and patients when deciding on optimal screening approaches. He suggests that when clinicians present the pros and cons of breast cancer screening to patients, having a high BMI should be presented as a "pro" argument and that shorter intervals between screenings should be considered for this group. He adds that women with a high BMI also may be at a greater risk of a worse prognosis due to the molecular composition of the tumors and hormone receptor expression levels that make the cancer more difficult to treat.
It should be noted that this study was conducted in Sweden, which recommends intervals of 18 to 24 months between screenings, in contrast to the 12-month intervals advised by some US organizations, although a 24-month screening interval is recommended by the US Preventive Services Task Force. In addition, there are fewer women in Sweden with high BMI compared with the United States.
PMID: 29509326
DOI: 10.1002/cncr.31301
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