Long-Term Follow-up Results of the DANTE Trial, a Randomized Study of Lung Cancer Screening with Spiral Computed Tomography
Maurizio Infante, Silvio Cavuto, Fabio Romano Lutman, Eliseo Passera, Maurizio Chiarenza, Giuseppe Chiesa, Giorgio Brambilla, Enzo Angeli, Giuseppe Aranzulla, Arturo Chiti, Marta Scorsetti, Pierina Navarria, Raffaele Cavina, Michele Ciccarelli, Massimo Roncalli, Anna Destro, Edoardo Bottoni, Emanuele Voulaz, Valentina Errico, Giorgio Ferraroli, Giovanna Finocchiaro, Luca Toschi, Armando Santoro, and Marco Alloisio
American Journal of Respiratory and Critical Care Medicine, Vol. 191, No. 10 (2015), pp. 1166-1175.
イタリアからの報告．
＜背景＞
肺がんを低線量のらせんＣＴ（ＬＤＣＴ）でスクリーニングすると，胸部Ｘ線（ＣＸＲ）でのスクリーニングと比べて肺がんの死亡率を２０％減少させることが報告されている．
しかし，一般住民を対象にした場合のＬＤＣＴの有効性についてははっきりしていない．
＜目的＞
ＬＤＣＴによるスクリーニングが検査なしの場合と比べて肺がんの死亡を下げるかを検証する．
２番目の目的は発生頻度，進行度，手術可能率である．
＜方法＞
２０pack-year以上の男性喫煙者で６０－７４歳がベースラインでＣＸＲと喀痰細胞診を行い，その後１年に１回のＬＤＣＴか１年に１回の問診を行った．
＜結果＞
１２６４名がＬＤＣＴ群に割りつけられ，１１８６名がコントロール群となった．
平均年齢は６４歳（四分位数５），平均喫煙は４５．０pack-yearであった．平均追跡期間は８．３５年．
ＬＤＣＴ群では１０４名（８．２３％）が肺がんと診断された（６６名はＣＴで診断）．
４７名（３．７１％）はステージ１の早期肺がんであった．
コントロール群では７２名（６．０７％）が肺がんと診断され，１６名（１．３５％）がステージ１だった．
ＬＤＣＴ群では肺がん死亡は１０万人年あたり５４３名であり，コントロール群では５４４名で有意差はなかった．
＜感想＞
統計学的限界のためかこのＤＡＮＴＥ試験ではＬＤＣＴの有用性は明確にならなかったようです．
健診を受けない群と比較するとまた結果は変わってくるのかもしれないと筆者らは述べています．
集団としてみた場合にＣＸＲあるいはＬＤＣＴの有用性の意義があるかどうかは，ＣＸＲについては欧米ではほぼその意義は否定的です．
ＬＤＣＴは集団をしぼれば有用という印象です．
しかし，個人にとってはＣＸＲ，ＬＤＣＴをすることで早期肺がんが見つかれば「してよかった」ということになるわけで，
このあたりが費用対効果と，（少数であっても）個人の利益の兼ね合いが難しいと感じています．
Rationale: Screening for lung cancer with low-dose spiral computed tomography (LDCT) has been shown to reduce lung cancer mortality by 20% compared with screening with chest X-ray (CXR) in the National Lung Screening Trial, but uncertainty remains concerning the efficacy of LDCT screening in a community setting.
Objectives: To explore the effect of LDCT screening on lung cancer mortality compared with no screening. Secondary endpoints included incidence, stage, and resectability rates.
Methods: Male smokers of 20+ pack-years, aged 60 to 74 years, underwent a baseline CXR and sputum cytology examination and received five screening rounds with LDCT or a yearly clinical review only in a randomized fashion.
Measurements and Main Results: A total of 1,264 subjects were enrolled in the LDCT arm and 1,186 in the control arm. Their median age was 64.0 years (interquartile range, 5), and median smoking exposure was 45.0 pack-years. The median follow-up was 8.35 years. One hundred four patients (8.23%) were diagnosed with lung cancer in the screening arm (66 by CT), 47 of whom (3.71%) had stage I disease; 72 control patients (6.07%) were diagnosed with lung cancer, with 16 (1.35%) being stage I cases. Lung cancer mortality was 543 per 100,000 person-years (95% confidence interval, 413–700) in the LDCT arm versus 544 per 100,000 person-years (95% CI, 410–709) in the control arm (hazard ratio, 0.993; 95% confidence interval, 0.688–1.433).
Conclusions: Because of its limited statistical power, the results of the DANTE (Detection And screening of early lung cancer with Novel imaging TEchnology) trial do not allow us to make a definitive statement about the efficacy of LDCT screening. However, they underline the importance of obtaining additional data from randomized trials with intervention-free reference arms before the implementation of population screening.
Read More: http://www.atsjournals.org/doi/abs/10.1164/rccm.201408-1475OC#.VXJE3LUw9dg