Overview of observational studies of low-dose helical computed tomography screening for lung cancer

Diagnostic utility of trefoil factor families for the early detection of lung cancer and their correlation with tissue expression

Trefoil factors (TFFs) are upregulated in numerous types of cancer, including those of the breast, the colon, the lung and the pancreas, suggesting their potential utility as biomarkers for screening. In the present study, the clinical relevance of serum or urinary TFFs as biomarkers were comprehensively evaluated and the correlation with TFF expression levels in lung cancer tissue was examined. Serum and urine were collected from 199 patients with lung cancer and 198 healthy individuals. Concentrations of serum and urinary TFF1, TFF2 and TFF3 were measured using ELISA and the potential of TFF levels to discriminate between cancer and non-cancer samples was evaluated. In 100 of the cancer cases, expression of TFF1-3 was analyzed using immunohistochemical staining of paraffin sections. Furthermore, the relationship between TFF levels and clinicopathological factors among these cancer cases was analyzed using immunohistochemistry of tissue specimens, quantified and statistically analyzed. While serum levels of all TFFs measured using ELISA were significantly higher in patients with lung cancer compared with those in healthy individuals, urinary TFFs were lower. Areas under the curve (AUC) of the receiver operating characteristic curves for serum/urinary TFF1, TFF2 and TFF3 were 0.709/0.594, 0.722/0.501 and 0.663/0.665, respectively. Furthermore, the combination of serum TFF1, TFF2, TFF3 and urinary TFF1 and TFF3 demonstrated the highest AUC (0.826). In the clinicopathological analysis, serum TFF1 was higher in the early pathological T-stage (pTis/1/2) compared with the later stage (pT3/4) and TFF2 was higher in the pN0/1 than the pN2 group. With regards to the histological types, urinary TFF1 was higher in squamous cell carcinoma than adenocarcinoma (AC), but TFF2 tended to be higher in AC. Using immunohistochemical analysis, although TFF1 and TFF3 expression showed positive correlation with serum concentrations, TFF2 was inversely correlated. In conclusion, serum and urinary TFF levels are promising predictive biomarkers, and their measurements provide a useful in vivo and non-invasive diagnostic screening tool. In particular, TFF1 and TFF3 could be surrogate markers of clinicopathological profiles of human lung cancer.

Psf3 as a possible biomarker of postoperative chemotherapy for patients with early pulmonary adenocarcinoma

BACKGROUND

Partner of Sld five 3 (Psf3) is a member of the heterotetrameric complex that consists of SLD5, Psf1, Psf2, and Psf3. We have shown in previous studies that high Psf3 expression was a poor prognostic marker for pulmonary adenocarcinoma. Here, we statistically evaluated the relationship between clinicopathologic factors and Psf3 expression in stage I pulmonary adenocarcinoma.

METHODS

A total of 583 patients who had undergone complete resection of stage I pulmonary adenocarcinoma from January 2002 to December 2009 were included in the study. Tissue microarrays were performed, and the resected tumors were divided into groups according to Psf3 expression.

RESULTS

Of 583 patients, high expression of Psf3 was observed in 211 (36.2%) and low expression of Psf3 observed in 372 (63.8%) patients. Among stage I patients, the five-year survival rate was 76.7% in the Psf3 high expression group and 90.9% in the Psf3 low expression group (P < 0.0001). On multivariate analysis, Psf3 was found to be the independent prognostic factor. Among stage I patients in the Psf3 high expression group, a significantly greater five-year survival rate was observed in patients who received postoperative chemotherapy with tegafur-uracil than in those who underwent surgery alone (P < 0.0001). In contrast, among stage I patients in the Psf3 low expression group, no difference was found in the five-year survival, regardless of the presence or absence of tegafur-uracil (P = 0.873).

CONCLUSION

The Psf3 expression was an independent prognostic factor and could be a biomarker of adjuvant tegafur-uracil for stage I pulmonary adenocarcinoma.

KEY POINTS

Significant findings of the study: The Psf3 expression could be a biomarker of adjuvant tegafur-uracil administration for stage I pulmonary adenocarcinoma.

WHAT THIS STUDY ADDS

Appropriate patients of adjuvant chemotherapy for stage I pulmonary adenocarcinoma using Psf3 expression could be selected.

[Classification and Risk-factor Analysis of Postoperative Cardio-pulmonary Complications after Lobectomy in Patients with Stage I Non-small Cell Lung Cancer]

背景与目的

随着医学技术的进步，医学检测手段的更新，体检筛查的普及以及社会健康意识的提高，越来越多的早期肺癌能够得到及时的发现并接受手术治疗，而关于患者术后并发症发生种类和高危因素的研究很少；针对Ⅰ期非小细胞肺癌（non-small cell lung cancer, NSCLC）术后并发症及其高危因素的研究，可为此类患者术后心肺相关并发症的预防、干预提供依据，并加速患者康复。

方法

回顾性分析2012年1月-2013年12月四川大学华西医院胸外科行肺叶切除的Ⅰ期NSCLC患者421例，以术后30天是否发生心肺相关并发症分为：并发症组和无并发症组。

结果

最终421例患者被纳入研究，其中64例为并发症组（15.2%, 64/421），357例为非并发症组（84.8%, 357/421）。421例患者中，发生肺部感染的比例最高（8.8%, 37/421），其他主要的并发症包括肺不张（5.9%, 25/421）、中量以上胸腔积液（5.0%, 21/421），持续性肺漏气（3.6%, 15/421）等；术前合并慢性阻塞性肺部疾病（chronic obstructive pulmonary disease, COPD）（P=0.027），术前白细胞计数（P < 0.001），中性淋巴比（neutrophil-lymphocyte ratio, NLR）（P < 0.001），术中出血量（P=0.034）以及手术时间（P=0.007）在两组间差异有统计学意义；采用二分类Logistics回归分析后发现，术前白细胞计数（OR=1.451, 95%CI: 1.212-1.736, P < 0.001）、术前合并COPD（OR=0.031, 95%CI: 0.012-0.078, P < 0.001）是术后发生心肺相关并发症的独立危险因素。

结论

术前白细胞计数以及术前合并COPD是Ⅰ期肺癌患者术后心肺相关并发症发生的独立危险因素，可能可以作为预测术后心肺相关并发症的可靠指标。

Status and perspectives of detection by low-dose computed tomography or computed radiography in surgical patients with lung cancer, based on a five-year study

Background

A retrospective study involving 502 lung cancer patients who had received pulmonary resection from 2009–2013 was conducted in order to compare the clinical characteristics of patients whose diagnosis was detected by low‐dose computed tomography (LDCT) and computed radiography (CR).

Methods

Two groups were established, based on the method of detection: the LDCT group included 172 lung cancer patients; the CR group included 330 lung cancer patients. The evolution of proportions of patients in urban and rural regions was also analyzed, according to detection method.

Results

The percentage of patients with stage I was higher in the LDCT group than in the CR group (77.3%, 133/172 vs. 53.6%, 177/330). The incidence of postoperative complications within 30 days was significantly lower in the LDCT than in CR group (25.0% vs. 33.6%). The proportion of patients detected by LDCT or CR in urban regions was constantly higher than in rural regions (with an increase of 13.0% vs. 5.9%); the proportion of LDCT‐detected patients in urban regions was constantly higher than in rural regions (with an increase of 8.7% vs. 5.9%).

Conclusions

LDCT contributes to a higher proportion of early lung cancer diagnoses and a lower incidence of postoperative complications in surgical patients. The proportions of patients detected early and by LDCT have both increased steadily during the last five years. These two trends are more pronounced in urban compared with rural patients.

A systematic review of the characteristics associated with recall rates, detection rates and positive predictive values of computed tomography screening for lung cancer

BACKGROUND

Low-dose computed tomography (LDCT) screening has been shown to reduce mortality from lung cancer but at a substantial cost in diagnostic activity. The objective of this study was to investigate the characteristics of screening programmes associated with recall rates, detection rates and positive predictive values (PPVs).

DESIGN

We conducted a systematic review of randomised trials and observational studies on LDCT screening for lung cancer. A meta-regression using random-effect logistic regressions was carried out to assess factors influencing recall rates for further investigation, cancer detection rates and PPVs of recall.

RESULTS

We used data from 63 372 prevalent screens from 16 studies of LDCT screening for lung cancer and 79 302 incident screens from nine studies. In univariable analysis, the use of a cut-off size to define nodules warranting further investigation at prevalent screens reduced recall rates [odds ratio (OR) = 0.44, 95% confidence interval (CI) 0.24-0.82 and OR = 0.42, 95% CI 0.21-0.84 for cut-off sizes of 3-4 and 5-8 mm, respectively], without significant changes in detection rates and PPVs. The number of readers (1 or ≥2) was not associated with changes in recall rates, detection rates and PPVs at prevalent and incident screens. Using the volumetry software at incident screens significantly increased the PPV (OR = 5.02, 95% CI 1.65-15.28) as a result of a decrease in recall rates (OR = 0.25, 95% CI 0.12-0.51), without significant changes in detection rates.

CONCLUSION

These results highlight the value of using a cut-off size for nodules warranting further investigation with lower recall rates at prevalent screens, whereas the volumetric assessment software at incident screens results in lower recall rates and higher PPVs. The presence of positron emission tomography in the work-up protocol might be associated with lower rates of surgical procedures for benign findings, although this hypothesis deserves further investigation.

Patient willingness and barriers to receiving a CT scan for lung cancer screening

CT scans are becoming a more common method for detecting lung cancers at an earlier, potentially more curable, stage of disease. There is currently little data on attitudes and beliefs about screening for lung cancer. This paper presents the results of a 2011 survey of adult current and former smokers that queried about past use of CT scanning and reasons for having or not having the screening done. A random-digit dialed telephone survey was administered to a representative sample of 1290 US adults. Logistic regression analyses were used to examine the correlates of having the test while controlling for the covariates. A total of 13.4% (n = 45) of the sample had ever had a CT scan to detect lung cancer. Of current smokers, 14.6% had received a CT scan, as compared with 12.7% of former smokers. The oldest age group (55+) was significantly more likely to have received a CT scan than the younger age groups. 78.5% of current smokers and 81.4% of former smokers indicated willingness to get the test if advised to do so by their doctor. Among those who said they were not willing to get screened, lack of insurance coverage was cited by 33% of current smokers and 25% of former smokers. Additionally, 33% of current smokers were afraid to find out whether they had cancer. The main barrier to CT scanning for lung cancer is likely to be insurance coverage for the test, which would be a burden for those on limited and fixed incomes. Next steps should include further research into the effect of increased public education about the availability, risks, benefits and barriers to lung cancer screening.

Diagnostic work-up and surgery in participants of the Gdansk lung cancer screening programme: the incidence of surgery for non-malignant conditions

OBJECTIVES

Low-dose computed tomography (LDCT) screening improves lung cancer prognosis but also results in diagnostic work-up and surgical treatment in many individuals without cancer. Therefore, we analysed the procedures that screening participants underwent to better understand the extent of overdiagnosis.

METHODS

Between 2009 and 2011, 8649 healthy volunteers aged 50-75 years with a 20 pack-year smoking history underwent LDCT screening, of whom individuals with detected lung nodules had 2 years control. Participants with a nodule >10 mm in diameter or with suspected tumour morphology underwent diagnostic work-up: 283 (6%)/4694 (54%) screened participants had detected lung nodules. One hundred and four individuals underwent surgery, 27 underwent oncological treatment and 152 without a cancer diagnosis underwent further follow-up with LDCT.

RESULTS

In 75% of participants accepted for diagnostic work-up and 25% of surgical patients, the procedures were unnecessary. In 70 (24.7%) participants, a specific diagnosis was obtained mainly due to the low efficacy of fine needle aspiration biopsy [sensitivity, 65.2%; negative predictive value (NPV), 95.9%] and bronchofiberoscopy (sensitivity, 71.4%; NPV, 50%) caused by overinterpretation of LDCT [positive predictive value (PPV), 2%]. Of 104 (36.7%) surgical patients, 43 (41.4%) had a preoperative cancer diagnosis, and 61 (58.6%) underwent surgery without pathological examination. In the latter group, intervention was justified in 35 (57.3%) patients. Complications occurred in 49 (17.3%) participants subjected to diagnostic work-up. In surgical patients, 67 (64.4%) malignant and 37 (35.6%) benign lesions were resected. In the latter group, intervention was justified in only 11 (29.7%) patients. No patient died because of diagnostic or treatment procedures during the study. The complication rate was 14.5% in the malignant and 10.8% in the benign groups. A neoplasm was found in 94 screening participants, of whom 67 (71.3%) underwent surgery; the remaining 27 (28.7%) patients were not surgical candidates. Adenocarcinoma accounted for 49/67 (73%) patients who underwent surgery for non-small-cell lung cancer (NSCLC); 56/67 (84%) patients had stage I NSCLC, and 26/67 (38%) underwent video-assisted thoracoscopic surgery lobectomy.

CONCLUSIONS

Futile diagnostic work-ups and operations must be reduced before LDCT screening can be broadly used. Stage I adenocarcinoma dominated in the NSCLC patients who underwent surgery.

Distinct outcome of stage I lung adenocarcinoma with ACTN4 cell motility gene amplification

BACKGROUND

Even if detected at an early stage, a substantial number of lung cancers relapse after curative surgery. However, no method for distinguishing such tumors has yet been established.

PATIENTS AND METHODS

The copy number of the actinin-4 (ACTN4) gene was determined by fluorescence in situ hybridization on tissue microarrays comprising 543 surgically resected adenocarcinomas of the lung.

RESULTS

Amplification (an increase in the copy number by ≥ 2.0 fold) of the ACTN4 gene was detected in two of seven lung adenocarcinoma cell lines and 79 (15%) of 543 cases of pathological stage I-IV lung adenocarcinoma. Multivariate analysis revealed that ACTN4 gene amplification was the most significant independent factor associated with an extremely high risk of death (hazard ratio, 6.78; P = 9.48 × 10(-5), Cox regression analysis) among 290 patients with stage I lung adenocarcinoma. The prognostic significance of ACTN gene amplification was further validated in three independent cohorts totaling 1033 patients.

CONCLUSIONS

Amplification of the ACTN4 gene defines a small but substantial subset of patients with stage I lung adenocarcinoma showing a distinct outcome. Such patients require intensive medical attention and might benefit from postoperative adjuvant chemotherapy.

Screening and early detection of lung cancer

The greatest news of the past year in this field was the first large-scale early detection trial that could prove a 20% reduction in lung cancer-related mortality by screening high-risk individuals with low-dose computed tomography (LDCT). Several expert groups and medical societies have assessed the data and concluded that LDCT screening for lung cancer is, however, not ready for large-scale population-based implementation. Too many open questions remain, such as definition of the at-risk population, timing and intervals of screening, optimal method of acquisition and interpretation of the images, how to handle (false) positive findings, and especially cost-effectiveness in relation to other lung cancer prevention strategies, mainly smoking cessation. Further analyses and several ongoing European trials are eagerly awaited. Much hope also resides in the use of biomarkers, as their use in, e.g., blood or exhaled air may provide more easy-to-use tests to better stratify high-risk populations for screening studies. While exciting research is ongoing in this domain--e.g. with microRNAs--none of the tests has yet reached sufficient validation for clinical use. Early central lung cancers are more difficult to visualise by CT. For these patients, standard bronchoscopy, complemented by autofluoresence endoscopy, has been studied in different screening and follow-up settings.

Screening and early detection of lung cancer

Lung cancer with an estimated 342,000 deaths in 2008 (20% of total) is the most common cause of death from cancer, followed by colorectal cancer (12%), breast cancer (8%), and stomach cancer (7%) in Europe. In former smokers, the absolute lung cancer risk remains higher than in never-smokers; these data therefore call for effective secondary preventive measures for lung cancer in addition to smoking cessation programs. This review presents and discusses the most recent advances in the early detection and screening of lung cancer.An overview of randomized controlled computerized tomography-screening trials is given, and the role of bronchoscopy and new techniques is discussed. Finally, the approach of (noninvasive) biomarker testing in the blood, exhaled breath, sputum, and bronchoscopic specimen is reviewed.

Lung cancer screening in the randomized Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial

BACKGROUND

The 5-year overall survival rate of lung cancer patients is approximately 15%. Most patients are diagnosed with advanced-stage disease and have shorter survival rates than patients with early-stage disease. Although screening for lung cancer has the potential to increase early diagnosis, it has not been shown to reduce lung cancer mortality rates. In 1993, the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was initiated specifically to determine whether screening would reduce mortality rates from PLCO cancers.

METHODS

A total of 77 464 participants, aged 55-74 years, were randomly assigned to the intervention arm of the PLCO Cancer Screening Trial between November 8, 1993, and July 2, 2001. Participants received a baseline chest radiograph (CXR), followed by three annual single-view CXRs at the 10 US screening centers. Cancers were classified as screen detected and nonscreen detected (interval or never screened) and according to tumor histology. The positivity rates of screen-detected cancers and positive predictive values (PPVs) were calculated. Because 51.6% of the participants were current or former smokers, logistic regression analysis was performed to control for smoking status. All statistical tests were two-sided.

RESULTS

Compliance with screening decreased from 86.6% at baseline to 78.9% at the last screening. Overall positivity rates were 8.9% at baseline and 6.6%-7.1% at subsequent screenings; positivity rates increased modestly with smoking risk categories (P(trend) < .001). The PPVs for all participants were 2.0% at baseline and 1.1%, 1.5%, and 2.4% at years 1, 2, and 3, respectively; PPVs in current smokers were 5.9% at baseline and 3.3%, 4.2%, and 5.6% at years 1, 2, and 3, respectively. A total of 564 lung cancers were diagnosed, of which 306 (54%) were screen-detected cancers and 87% were non-small cell lung cancers. Among non-small cell lung cancers, 59.6% of screen-detected cancers and 33.3% of interval cancers were early (I-II) stage.

CONCLUSIONS

The PLCO Cancer Screening Trial demonstrated the ability to recruit, retain, and screen a large population over multiple years at multiple centers. A higher proportion of screen-detected lung cancers were early stage, but a conclusion on the effectiveness of CXR screening must await final PLCO results, which are anticipated at the end of 2015.

Low-dose CT: a useful and accessible tool for the early diagnosis of lung cancer in selected populations

OBJECTIVE

An evaluation is made of the effectiveness of low-dose computed tomography (LDCT) in diagnosing early stage lung cancer in the Autonomous Community of Madrid (Spain).

METHODS

The study comprised subjects over 50 years of age who were active smokers (or who had stopped smoking up to 6 months previously) who smoked more than 30 cigarettes daily for at least 15 years, or 20 cigarettes daily for 20 years, or more than 10packs/year and in contact with asbestos at work. The study group was evaluated using LDCT. For all participants in whom LDCT showed no pathological findings, or in those cases classified as benign, a new LDCT scan was performed 2 years after the first. In case of doubt regarding the benign nature of the findings, an assessment algorithm was applied.

RESULTS

Among the initial 482 candidates in the study group, 466 LDCT scans were performed at baseline, revealing 9 extrapulmonary lesions and 114 pulmonary lesions in 98 subjects. The latter raised diagnostic doubts in 32 cases; of these, 15 were confirmed as benign by high resolution computed tomography (HRCT). In the remaining 17 cases, stage IAp adenocarcinoma was diagnosed at baseline (0.2%). With LDCT after 2 years, an additional four adenocarcinomas were diagnosed-all in stage IAp (0.98%). The complete study, including prevalence cut-off and incidence calculation after 2 years, resulted in the diagnosis of five cancers (1.1%) and two false positive cases (28%).

CONCLUSIONS

The use of low-dose computed tomography in risk groups is valid for the early diagnosis of bronchogenic cancer. Nevertheless, significant problems remain, particularly those associated with false positive interpretations. The results of randomized studies on lung cancer mortality such as the US NLST trial and the Dutch-Belgian NELSON trial have to be awaited before any conclusion regarding the effectiveness of LDCT screening can be drawn.

Should we screen for occupational lung cancer with low-dose computed tomography?

OBJECTIVE

The objective of this study was to assess the potential value of screening for occupational lung cancer through the use of low-dose computed tomography (LDCT).

METHODS

A literature review of Medline was conducted to assess: 1) screening studies of occupational lung cancer that used LDCT; 2) screening studies of nonoccupational lung cancer that used LDCT; and 3) position papers of medical professional societies and nongovernmental health organizations that have addressed the value of screening for lung cancer with LDCT.

RESULTS

No screening studies of occupational lung cancer with LDCT were uncovered; however, numerous observational and population-based studies have addressed the value of screening for lung cancer among cigarette smokers. Results of these studies are difficult to interpret in light of numerous biases associated with these types of studies. No randomized, controlled studies on screening for lung cancer have been published at this time. No professional, governmental, or nonprofit health organization recommends screening asymptomatic people at risk of lung cancer with LDCT at this time.

CONCLUSION

In the absence of randomized, controlled studies that can address biases commonly encountered in observational and population-based studies, it is unclear whether LDCT reduces mortality from lung cancer. The National Cancer Institute is sponsoring a randomized, controlled study of over 50,000 current and former smokers with the results expected in 2009.