据英国媒体25日报道，研究人员在经过真对挪威女性患乳腺癌几率的调查之后，近日提出争议性观点：部分乳腺癌可能会自动痊愈；有一些乳房X光造影检查下的肿瘤如果未被查出来，也许本来就有可能自动消失。此项研究结果刊登在最新一期的《内科学文献集》上。
乳腺癌是女性最常见的恶性肿瘤之一，它会严重影响妇女身心健康甚至危及生命。据资料统计，发病率占全身各种恶性肿瘤的7-10%，对妇女来讲仅次于子宫癌。它的发病常与遗传有关，在40—60岁之间、绝经期前后的妇女发病率较高。
但是，癌症专家对此观点表示怀疑，并敦促女性继续接受常规的乳房X光造影检查，称该技术可以帮助及早发现乳腺癌，赶上最佳治疗时间。乳腺细胞发生突变后便丧失了正常细胞的特性，组织结构紊乱、细胞连接松散；癌细胞很容易脱落游离，随血液或淋巴液等播散全身，形成早期的远端转移，这给乳腺癌的临床治愈增加了很大的困难。
挪威奥斯陆公共卫生研究所汉瑞克-扎尔医师及其美国同事对近12万名年龄在50-64岁、妇女患上侵入性乳腺癌的几率进行了跟踪研究。这12万名女性每两年接受一次乳房X光造影检查，这种习惯持续6年。另一组年龄相仿、背景相似的11万挪威女性之中，研究人员只在第6年年底对她们进行检查；然后将两组人群的数据加以对比。
研究人员表示，他们原本以为，两组人群患癌几率不会有所不同。但事实上却是，在两年接受一次乳房X光造影检查的人群患侵入性乳腺癌的几率比另一组人群高22%。扎尔表示，这一发现显示了某些肿瘤会自动消失的可能，但目前还无法对此做出生物学解释。
扎尔在电话采访中说：“我们首次发表了这种理论，我们认为，有很多肿瘤可能已经自动消失，因而在之后的检查中没有再查出。但现在，我并无法从生物学角度解释这一问题。”（生物谷Bioon.com）
生物谷推荐原始出处：
Arch Intern Med. 2008;168(21):2311-2316.
The Natural History of Invasive Breast Cancers Detected by Screening Mammography
Per-Henrik Zahl, MD, PhD; Jan M?hlen, MD, PhD; H. Gilbert Welch, MD, MPH
Background The introduction of screening mammography has been associated with sustained increases in breast cancer incidence. The natural history of these screen-detected cancers is not well understood.
Methods We compared cumulative breast cancer incidence in age-matched cohorts of women residing in 4 Norwegian counties before and after the initiation of biennial mammography. The screened group included all women who were invited for all 3 rounds of screening during the period 1996 through 2001 (age range in 1996, 50-64 years). The control group included all women who would have been invited for screening had there been a screening program during the period 1992 through 1997 (age range in 1992, 50-64 years). All women in the control group were invited to undergo a 1-time prevalence screen at the end of their observation period. Screening attendance was similar in both groups (screened, 78.3%, and controls, 79.5%). Counts of incident invasive breast cancers were obtained from the Norwegian Cancer Registry (in situ cancers were excluded).
Results As expected, before the age-matched controls were invited to be screened at the end of their observation period, the cumulative incidence of invasive breast cancer was significantly higher in the screened group than in the controls (4-year cumulative incidence: 1268 vs 810 per 100 000 population; relative rate, 1.57; 95% confidence interval, 1.44-1.70). Even after prevalence screening in controls, however, the cumulative incidence of invasive breast cancer remained 22% higher in the screened group (6-year cumulative incidence: 1909 vs 1564 per 100 000 population; relative rate, 1.22; 95% confidence interval, 1.16-1.30). Higher incidence was observed in screened women at each year of age.
Conclusions Because the cumulative incidence among controls never reached that of the screened group, it appears that some breast cancers detected by repeated mammographic screening would not persist to be detectable by a single mammogram at the end of 6 years. This raises the possibility that the natural course of some screen-detected invasive breast cancers is to spontaneously regress.
Author Affiliations: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway (Dr Zahl); Department of Pathology, Ullev?l University Hospital, Oslo (Dr M?hlen); and the VA Outcomes Group, Department of Veterans Affairs Medical Center, White River Junction, Vermont, and the Dartmouth Institute for Health Policy and Clinical Practice, Hanover, New Hampshire (Dr Welch).
