4月3日，《內(nèi)科學(xué)年鑒》（Annals of Internal Medicine）雜志發(fā)表的一項(xiàng)研究結(jié)果表明，乳房X線(xiàn)篩查可能與15%~25%的“過(guò)度診斷性”乳腺癌有關(guān),。哈佛公共衛(wèi)生學(xué)院的Mette Kalager博士介紹，這與既往其他國(guó)家的研究結(jié)果一致,，后者報(bào)告的估計(jì)過(guò)度診斷率為0%~54%不等,，隨機(jī)對(duì)照試驗(yàn)報(bào)告的過(guò)度診斷率約為30%。
這項(xiàng)挪威研究的結(jié)果進(jìn)一步表明,，對(duì)非致死性癌癥的過(guò)度診斷和不必要的治療,，會(huì)帶來(lái)不容忽視的倫理和臨床問(wèn)題,，而且會(huì)使人懷疑是否有必要繼續(xù)開(kāi)展乳房X線(xiàn)篩查。
自從1996年開(kāi)展政府資助的乳房X線(xiàn)篩查項(xiàng)目以來(lái),，這一篩查在挪威逐漸變得常見(jiàn),，但各地的推廣進(jìn)程并不一致，經(jīng)過(guò)10年時(shí)間才實(shí)現(xiàn)了普遍推廣,。自2005年以后,，挪威所有50~69歲女性均被建議每2年篩查1次，其中約77%依從了這一建議,。“推廣進(jìn)程的不一致為研究者提供了機(jī)會(huì),，得以比較開(kāi)展和未開(kāi)展篩查的地區(qū)的乳腺癌發(fā)病率和過(guò)度診斷情況，并且使研究者可以用兩種方法進(jìn)行評(píng)估,。”
該研究中的過(guò)度診斷是指,，假如不接受篩查一生中都不會(huì)出現(xiàn)臨床癥狀的乳腺癌。即乳腺癌永遠(yuǎn)不會(huì)進(jìn)展為臨床期,，或者在乳腺癌出現(xiàn)臨床表現(xiàn)之前患者已死于其他原因,，因此這類(lèi)患者獲得診斷和治療不會(huì)帶來(lái)任何生存益處。
該研究的對(duì)象包括39,888例在1996~2005年期間被診斷為侵襲性乳腺癌的女性,，其中27,238例診斷時(shí)年齡為50~79歲,。共有7,793例在開(kāi)始常規(guī)篩查后獲得診斷。
采用第一種估計(jì)方法的完全校正分析顯示,，在乳房X線(xiàn)篩查中發(fā)現(xiàn)的乳腺癌病例中有15%~20%——即1,169~1,948例——屬于過(guò)度診斷,。采用第二種估計(jì)方法進(jìn)行分析，18%~25%的病例為過(guò)度診斷,。因此,，總體過(guò)度診斷率為15%~25%。
而且,，進(jìn)展期乳腺癌的比例隨著時(shí)間推移而逐漸下降,，篩查組與未篩查組降至同一水平，而Ⅰ期乳腺癌的比例僅在篩查組女性中顯著增加,。這一結(jié)果提示,，乳房X線(xiàn)篩查發(fā)現(xiàn)的乳腺癌幾乎均為早期、低危腫瘤,。“我們的結(jié)果提示,，晚期癌癥較少可能是患者更加警惕的結(jié)果，而不是篩查本身的功勞,。”
華盛頓大學(xué)的Joann G. Elmore博士和哈佛醫(yī)學(xué)院的Suzanne W. Fletcher博士在隨刊述評(píng)中指出：“沒(méi)必要太糾結(jié)于過(guò)度診斷的確切范圍,，當(dāng)務(wù)之急是意識(shí)到任何程度的過(guò)度診斷都是嚴(yán)重的，必須盡快解決這一問(wèn)題。”一種減少過(guò)度診斷的方法是,，調(diào)整乳房X線(xiàn)檢查結(jié)果的“異常”閾值,。同時(shí)，對(duì)于確定的病變可以建議繼續(xù)嚴(yán)密觀察而不必立即活檢(Ann. Intern. Med. 2012;156:536-7),。“我們有義務(wù)告知女性這種過(guò)度診斷現(xiàn)象,，而實(shí)際上多數(shù)患者教育都沒(méi)有提及這一問(wèn)題。”
Elmore博士在非營(yíng)利性醫(yī)療決策告知基金會(huì)出版的患者教育材料中擔(dān)任了醫(yī)學(xué)編輯,，F(xiàn)letcher博士報(bào)告稱(chēng)從事乳腺癌篩查達(dá)36年之久,，并在1980年代早期為美國(guó)預(yù)防服務(wù)工作組提供了服務(wù)。這項(xiàng)研究獲得了挪威前沿科學(xué)研究理事會(huì)的支持,。Kalager博士及其合著者無(wú)利益沖突披露,。（生物谷Bioon.com）
Doi:
PMC:
PMID:22473436
Overdiagnosis of Invasive Breast Cancer Due to Mammography Screening: Results From the Norwegian Screening Program
Mette Kalager, MD; Hans-Olov Adami, MD, PhD; Michael Bretthauer, MD, PhD; and Rulla M. Tamimi, ScD
Background: Precise quantification of overdiagnosis of breast cancer (defined as the percentage of cases of cancer that would not have become clinically apparent in a woman's lifetime without screening) due to mammography screening has been hampered by lack of valid comparison groups that identify incidence trends attributable to screening versus those due to temporal trends in incidence.
Objective: To estimate the percentage of overdiagnosis of breast cancer attributable to mammography screening.
Design: Comparison of invasive breast cancer incidence with and without screening.
Setting: A nationwide mammography screening program in Norway (inviting women aged 50 to 69 years), gradually implemented from 1996 to 2005.
Participants: The Norwegian female population.
Measurements: Concomitant incidence of invasive breast cancer from 1996 to 2005 in counties where the screening program was implemented compared with that in counties where the program was not yet implemented. To adjust for changes in temporal trends in breast cancer incidence, incidence rates during the preceding decade were also examined. The percentage of overdiagnosis was calculated by accounting for the expected decrease in incidence following cessation of screening after age 69 years (approach 1) and by comparing incidence in the current screening group with incidence among women 2 and 5 years older in the historical screening groups, accounting for average lead time (approach 2).
Results: A total of 39 888 patients with invasive breast cancer were included, 7793 of whom were diagnosed after the screening program started. The estimated rate of overdiagnosis attributable to the program was 18% to 25% (P < 0.001) for approach 1 and 15% to 20% (P < 0.001) for approach 2. Thus, 15% to 25% of cases of cancer are overdiagnosed, translating to 6 to 10 women overdiagnosed for every 2500 women invited.
