Academic journal article Public Health Reviews; Rennes

Why and How Would We Implement a Lung Cancer Screening Program?

Academic journal article Public Health Reviews; Rennes

Why and How Would We Implement a Lung Cancer Screening Program?

Article excerpt

Introduction

In 2007, we discussed the situation and perspective of lung cancer screening [1]. At that time, we presented the high mortality of lung cancer, described the promising screening modalities, and characterized the ongoing and planned trials. Overall, we concluded that until the completion of these trials, widespread lung cancer screening intervention should be avoided. Eight years and a large randomized clinical trial (RCT) later, we propose to discuss why and how we would implement a lung cancer screening program, if any. In this narrative review, we briefly review the current evidence regarding the influence of lung cancer screening on lung cancer mortality as well as the major issues and limitations related to lung cancer screening. We then discuss the different factors that should be considered when designing and implementing a lung cancer screening program.

Why would we implement a lung cancer screening program?

Several reasons can motivate the implementation of a lung cancer screening program. These reasons include the decade-long burden of lung cancer, the lack of meaningful improvement in lung cancer prognosis, the identification of a well-defined population at high risk of lung cancer, and the evidence from a large, well-designed RCT.

Burden of lung cancer

Lung cancer represents a huge public health burden. Worldwide, it is the leading cause of death from cancer, with 1.6 million deaths reported each year [2]. It affects both males and females, in which it is either the first or second (respectively) leading cause of death from cancer [3]. In fact, lung cancer causes more deaths than do colorectal, breast, and prostate cancer combined [1].

A remarkable observation that contrasts with other frequent cancers in adults is that the 5-year survival rate of lung cancer remains -in 2015- very low. In developed countries, the overall 5-year survival rate is 20 % or less [4]. This is because lung cancer is generally diagnosed at late stages, when treatments do not improve the prognosis. The poor chance of cure at late stages of lung cancer contrasts with the 80 % 5-year survival rate observed when treatment is initiated at an early stage [5].

Although mortality trends differ between countries, even within the European region (Fig. 1), this grim situation has existed for decades, and novel treatment modalities that could improve the 5-year survival rate of lung cancer are not well established [6]. [ Table Omitted - see PDF ]

From August 2002 through April 2004, 53,454 participants were randomly assigned to annual LDCT lung cancer screening scans versus chest X-ray for three consecutive years in 33 different sites. The eligible participants were high-risk people, defined as adults aged 55-74 years who had smoked at least 30 pack years or former smokers who had quit 15 years ago or less. The NLST participants appeared to be younger, more educated, and more frequently former smokers than the comparable US eligible population [18, 19]. Adherence to screening was very high (93 %) in both arms [20]. In the case of positive findings (i.e., LDCT arm: at least one noncalcified nodule ?4 mm in longest diameter or other abnormality suspicious for lung cancer; and chest X-ray arm: any noncalcified nodule or mass), decisions about how to proceed were left to the referring physician [2].

The incidence of lung cancer was 645 cases per 100 000 person years (1060 cancers) in the LDCT group compared with 572 cases per 100 000 person years (941 cancers) in the chest X-ray arm. In the LDCT screening arm, 356 deaths from lung cancer occurred (247 per 100 000 person-years) compared with 443 deaths (309 per 100 000 person-years) in the chest X-ray arm. After a 6.5-year median follow-up, the trial found that lung cancer mortality was reduced from 1.7 % in the chest X-ray arm to 1.4 % in the LDCT arm, a statistically significant relative risk reduction of 20 % (95 % CI, 6.8 to 26.7 %). The trial also showed a statistically significant relative reduction of 6. …

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