Lung cancer mortality in the Mayo Lung Project: impact of extended follow-up

A half-yearly chest radiograph for early detection of lung cancer following oral cancer

In a retrospective analysis of 339 patients, treated with a curative intention for a squamous cell carcinoma of the oral cavity between 1988-1996, the value of a half-yearly routine chest radiograph during the first 2 years of follow-up, was evaluated. Metastatic or primary lung malignancies developed in 18 (5.3%) of the 339 patients in the first 2 years of the follow-up. In 11 (3.2%) patients these malignancies were detected on routine chest radiographs while in 7 (2.0%) patients these were detected on chest radiographs taken because of pulmonary complaints. The mean survival after detection of the pulmonary malignancy was 8 months. All patients died within 21 months, independent of pathology or therapy. No correlation was found between stage, location or differentiation of the primary tumour. As a result of this study it can be concluded that there is no benefit for the patient for a 6-month thoracic radiograph in routine follow-up for patients with oral squamous cell carcinoma. It gives false certainty and burdens the health care system.

An evaluation of chest X-ray screening for lung cancer in gunma prefecture, Japan: a population-based case-control study

In order to evaluate the efficacy of annual chest X-ray screening for lung cancer, a case-control study was conducted in Gunma Prefecture, Japan. Population-based annual lung cancer screening programmes have been conducted by the local government in Gunma Prefecture since the mid-1970s. A total of 121 case subjects, including 91 high-risk males and 30 non-high-risk females between the ages of 40 and 79 years who died of lung cancer from 1992 to 1997 were evaluated. A total of 536 controls (3-5 controls for each case) were matched to case subjects by gender, year of birth, address and smoking habits. Controls were selected from screening programme lists provided by the local governments. All case subjects were also included on these lists. The smoking-adjusted odds ratio (OR) of lung cancer death for those subjects screened within 12 months prior to diagnosis versus those not screened was 0.68 (95% confidence interval (CI): 0.44-1.05; P=0.084). When the analysis was conducted without matching case and control subjects by smoking habits, the OR was 0.79 (95% CI: 0.53-1.18). When stratified by histological type, the OR was 0.62 (95% CI: 0.31-1.24) for adenocarcinoma, and 1.01 (95% CI: 0.44-2.31) for squamous cell carcinoma. The results of this study suggest 20-30% of deaths attributable to lung cancer, especially adenocarcinoma, might be prevented by annual chest X-rays.

New concepts in lung cancer screening

Although spiral CT has an undeniably impressive ability to detect occult lung cancers in asymptomatic smokers, it is not clear whether screening this patient group will lead to a reduction in disease-specific mortality. The specter of overdiagnosis in lung cancer screening, which manifested during the chest radiograph trials of the 1970s and 1980s, still hangs over screening regimes today. The detection of premalignant lesions by molecular medicine techniques and fluorescence bronchoscopy may allow the development of novel treatments for preinvasive disease, but it is likely that radiologic means of detection will form the front line of any near future screening program. The proposed screening techniques may be new, but their use must be tested against tried and trusted standards of medical practice.

The Mayo Lung Cohort: a regression analysis focusing on lung cancer incidence and mortality

PURPOSE

The Mayo Lung Project has been interpreted as negative because it failed to demonstrate a significant mortality reduction among those randomized to chest x-ray and cytology. In contrast, survival suggests that screening is highly effective. This report was undertaken to analyze the trial as a closed cohort study, in an effort to identify predictors of lung cancer incidence and mortality, and to determine whether survival or mortality was unbiased.

PATIENTS AND METHODS

The Mayo Lung Cohort comprised all 9,192 randomized individuals. Cox proportional hazards regression was used both to determine predictors of incidence and mortality in the population and to identify predictors of mortality among cases. Survival analyses using intent-to-treat principles and measuring survival from randomization were used to evaluate length bias and lead-time bias. Multivariate Cox regression was used to investigate the extent to which the data are consistent with overdiagnosis.

RESULTS

Cox regression demonstrates that, in addition to age and smoking, randomization to screening predicted increased lung cancer incidence (hazard ratio, 1.30; 95% confidence interval [CI], 1.06 to 1.60). Predictors of mortality were similar, except randomization to screening was not significant (hazard ratio, 1.06; 95% CI, 0.83 to 1.37). Among cases, survival was significantly superior in the experimental population. Higher incidence in the experimental group accounts for the mortality/survival discrepancy. Both lead-time and length biases can be excluded, because survival from randomization was superior in the experimental population. Overdiagnosis is eliminated because resection was the only significant multivariate predictor of survival. Overall, 50% of resected and 0% of unresected cases were cured.

CONCLUSION

Survival was superior in the screened population, and this advantage was not attributable to lead-time bias, length bias, or overdiagnosis bias. Mortality was biased, because incidence differences confounded the ability of mortality to reflect the true effect of screening. Indeed, survival provided an unbiased surrogate for cure in the Mayo Lung Cohort.

Screening for early lung cancer with low-dose spiral CT: prevalence in 817 asymptomatic smokers

PURPOSE

To present prevalence screening data from a nonrandomized screening trial by using low-dose computed tomography (CT) and a simple algorithm based on the size and attenuation of detected nodules to guide diagnostic work-up.

MATERIALS AND METHODS

Eight hundred seventeen asymptomatic volunteers (age range, 40-78 years; median age, 53 years; median tobacco consumption, 45 pack-years) underwent spiral low-dose CT of the chest without contrast material enhancement. We regarded all noncalcified pulmonary nodules greater than 10 mm in diameter as potentially malignant and recommended histologic examination or follow-up after 3, 6, 12, and 24 months to exclude growth. For noncalcified pulmonary nodules of 10 mm or smaller, repeat low-dose CT was recommended to exclude growth.

RESULTS

In 43% (350 of 817) of individuals, 858 noncalcified pulmonary nodules were found. Thirty-two nodules in 29 subjects were larger than 10 mm. Biopsy of 15 lesions revealed lung cancer in 12 lesions in 11 subjects (prevalence for all ages, 1.3% [11 of 817 subjects]; >50 years of age, 2.1% [11 of 519 subjects]; >60 years of age, 3.9% [eight of 206 subjects]), with a high proportion of early tumor stages (seven tumors, stage I; two, stage II; and three, stage III); three lesions were benign. In 17 nodules larger than 10 mm, follow-up with low-dose CT for a minimum of 24 months did not demonstrate growth.

CONCLUSION

Lung cancer screening with low-dose CT demonstrated a prevalence of asymptomatic cancers in 1.3% of a smoking population, including a high proportion of early tumor stages and a 20% (three of 15) rate of invasive procedures for benign lesions.

Computed tomography screening for lung cancer

The development of CT technology reopened the lung cancer screening debate. Computed tomography screening for lung cancer certainly meets all the criteria required for an appropriate screening test. First and perhaps most importantly, the disease for which the screening is being performed should have a significant prevalence in the population being studied and be a significant health risk for those afflicted with it. Lung cancer is the leading cause of cancer death in both men and women, and one of the most lethal of all cancers.

Screening for lung cancer with low-dose spiral computed tomography

Studies suggest that screening with spiral computed tomography can detect lung cancers at a smaller size and earlier stage than chest radiography can. To evaluate low-radiation-dose spiral computed tomography and sputum cytology in screening for lung cancer, we enrolled 1,520 individuals aged 50 yr or older who had smoked 20 pack-years or more in a prospective cohort study. One year after baseline scanning, 2,244 uncalcified lung nodules were identified in 1,000 participants (66%). Twenty-five cases of lung cancer were diagnosed (22 prevalence, 3 incidence). Computed tomography alone detected 23 cases; sputum cytology alone detected 2 cases. Cell types were: squamous cell, 6; adenocarcinoma or bronchioalveolar, 15; large cell, 1; small cell, 3. Twenty-two patients underwent curative surgical resection. Seven benign nodules were resected. The mean size of the non-small cell cancers detected by computed tomography was 17 mm (median, 13 mm). The postsurgical stage was IA, 13; IB, 1; IIA, 5; IIB, 1; IIIA, 2; limited, 3. Twelve (57%) of the 21 non-small cell cancers detected by computed tomography were stage IA at diagnosis. Computed tomography can detect early-stage lung cancers. The rate of benign nodule detection is high.

Follow-up of local (stage I and stage II) non-small-cell lung cancer after surgical resection

Non-small-cell lung cancer (NSCLC) is responsible for more deaths each year in the United States than is any other malignancy. Early stage disease can be cured with surgical resection. Postoperative surveillance for recurrent disease and the development of second malignancies are important parts of the overall treatment plan. Follow-up strategies have been analyzed and guidelines (most notably those of the National Comprehensive Cancer Network ) have been published. However, common practice often does not comply with these rationally developed guidelines. Understanding the general principles of effective surveillance may improve compliance with the guidelines and may lead to more cost-effective management. New methods of surveillance, postoperative risk stratification, and emerging therapies may alter these recommendations for postoperative surveillance of patients with early stage NSCLC in the future.

Natural history of pure ground-glass opacity after long-term follow-up of more than 2 years

BACKGROUND

Pure ground-glass opacity (PGGO) is a new entity that has been clearly defined on high-resolution computed tomography (CT) during the last half decade. It is important to investigate the natural history of PGGO through long-term observation for the management of this new entity.

METHODS

We investigated 19 patients with PGGO(s) defined on high-resolution computed tomography and retained as PGGO for more than 2 years. The PGGOs of 11 patients were detected at annual mass screening by low-radiation-dose CT (low-dose CT), 7 at follow-up CT after cancer resection, and 1 incidentally on CT. After long-term observation, 10 of 19 patients underwent operation and 9 are currently being followed-up with CT. Their growth characteristics and histologic findings are reported.

RESULTS

The median follow-up period was 32 months, ranging from 24 to 124 months. The sizes of PGGOs at the time of discovery were 4 to 18 mm in largest diameter (average 8.6 mm). During follow-up, the size of PGGO showed no change in 8 patients, increased slightly (up to 5 mm) in 6 patients, and increased by more than 5 mm in 5 patients. Ten patients had limited resection (segmentectomy or wide wedge resection) with negative surgical margin by intraoperative lavage cytology of the resection margin of the lung. Of them, 5 patients had adenocarcinoma, 3 pulmonary lymphoproliferative disorder, and 1 each atypical adenomatous hyperplasia and focal fibrosis. There was no clear tendency between the degree of size change and histology. In all but 1 of 9 patients with follow-up only, the PGGOs showed either no change or only a slight increase within 5 mm in largest diameter.

CONCLUSIONS

These data suggest that some PGGOs will never progress to clinical disease and would be included in the category of overdiagnosis bias. However, a prior history of lung cancer should significantly raise the index of suspicion, as 4 of 5 proven cancer cases in this small series fell into that category. Because of the difficulties of preoperative and intraoperative histodiagnosis of PGGO, minimally invasive surgery may be appropriate from the viewpoints of both diagnosis and curability.

Stage distribution in patients with a small (< or = 3 cm) primary nonsmall cell lung carcinoma. Implication for lung carcinoma screening

BACKGROUND

Recently, there has been increased interest in the use of computed tomography (CT) for lung carcinoma screening. For this technique to be effective, small tumors must be detected at an earlier stage than large lesions. However, to the authors's knowledge, the relationship between the size of small primary (< or = 3 cm) neoplasms and disease stage at presentation has never been established clearly. The current study was performed to determine whether smaller lesions indeed have an earlier stage distribution compared with larger tumors.

METHODS

The Duke University Medical Center Tumor Registry identified 620 patients (261 women and 359 men, with a mean age of 67 years) who presented with pathologically proven primary nonsmall cell lung carcinomas measuring < or = 3 cm between 1980-1999. Surgical, pathologic, and imaging information was reviewed retrospectively to confirm the size of the lesion and the disease stage at the time of presentation. The distribution of tumor size within each stage and the distribution of disease stage according to tumor size were determined.

RESULTS

Tumors occurring in patients with TNM Stage IIIB disease were slightly larger than those found in patients with either more advanced or less advanced disease. However, there was no apparent statistically significant relation between the stage distribution and the size of the primary lesion.

CONCLUSIONS

The current study data did not find a statistically significant relation between the size of small primary lung tumors and the distribution of disease stage at the time of presentation. This finding suggests that the detection of small tumors using screening CT may not result in a shift to an earlier disease stage distribution. A reduction in mortality needs to be demonstrated by appropriate clinical trials prior to the initiation of mass CT screening programs.

A case-control study of lung cancer screening in Okayama Prefecture, Japan

The effectiveness of lung cancer screening in reducing mortality still remains uncertain. In order to evaluate the efficacy of lung cancer screening, a case-control study was conducted in Okayama Prefecture, Japan. The study area consisted of 34 municipalities where a population-based lung cancer screening had been conducted. Chest X-ray examinations for all participants and sputum cytology for high-risk participants were offered annually. The cases analyzed in this study consisted of 412 individuals aged between 40 and 79 who died of lung cancer. A total of 3490 controls, two to ten for each case matched by gender, year of birth, and living district were randomly collected. Screening histories of cases were compared with those of and matched controls for the identical calendar period prio to diagnosis of the case. Smoking adjusted odds ratio (OR) of death from lung cancer for screened individuals versus unscreened, within 12 months before diagnosis, was calculated as 0.59 (95% confidence interval: 0.46-0.74; P=0.0001). The OR for women (0.39, 95% confidence interval: 0.24-0.64) was lower than that for men (0.67, 95% confidence interval: 0.51-0.87), although both were statistically significant. These results suggest that lung cancer screening contributes to reducing lung cancer mortality by 41%.

CT screening for lung cancer: coping with nihilistic recommendations

The practicing radiologist today is well persuaded that earlier diagnosis of lung cancer can be achieved with traditional-type radiography and especially with modern computed tomography. The practitioner also is confident that intervention in the context of earlier diagnosis is more effective in preventing death due to this otherwise fatal disease. The practitioner is thus inclined to consider such screening in a high-risk person with suitably long life expectancy, especially when asked to provide it. On the other hand, the practitioner is aware of official recommendations against lung cancer screening, said to be based on demonstrated lack of effectiveness of traditional radiographic screening. Some researchers have expressed concerns about screening-associated "overdiagnosis." Given this dilemma, the critically thinking practitioner is concerned to understand the foundation of the official nihilism in evidence and reasoning, as she or he suspects that something may be seriously wrong in this. This article is an attempt to help such a practitioner in this effort--an effort that in the end is rewarded by the comforting realization that the nihilistic recommendations and hesitation-provoking cautions are founded on pseudoevidence and specious reasoning.

The role of photodynamic therapy in the management of stage I/II NSCLC

There is a resurgence of interest in lung cancer screening, motivated by the fact that many lung cancer patients cannot be cured due to advanced disease at presentation. Lung cancer screening may detect more early stage disease. Very early stage squamous cell type lung cancer in the central tracheobronchial tree can be detected and local bronchoscopic treatments such as photodynamic therapy can be applied if the tumor is strictly intraluminal and nodal disease is absent. So, accurate staging regarding tumor size and nodal disease is much more important than treatment per se. Bronchoscopic treatments are less morbid treatment alternatives than surgery and surgical bronchoplasty, especially for patients suffering from COPD and who have poor cardiovascular status due to their smoking history.

CT screening for lung cancer: not ready for routine practice

Lung cancer continues to be a major worldwide health problem. Multiple strategies are being explored in an attempt to reduce lung cancer mortality, including a renewed interest in screening. Multiple low-dose spiral computed tomography (CT) trials have been proposed, as proponents predict that small nodules will represent early-stage disease and detecting them will ultimately translate into improvements in outcomes. At this time, however, only prevalence-screening data are available, and it remains to be seen if CT will truly reduce mortality. The appropriate hypothesis-driven studies still must be performed and the results carefully analyzed before CT screening for lung cancer can be accepted as the standard of care.

Fluorescence bronchoscopy for early detection of lung cancer: a clinical perspective

The conventional method of bronchoscopy has only a 30% sensitivity to detect early stage cancer in the central airways. For patients with positive sputum cytology who clearly harbor early cancers, repeat and lengthy sessions of bronchoscopies are required for accurate localization of these lesions. This leads to a significant delay in obtaining the diagnosis, postponing an appropriate treatment and reduces the chance for cure. There are valid reasons for improving the detection rate of early stage lung cancers. The number of individuals at risk forms a large population, the outcome of patients treated with early stage cancer has been shown to be better and bronchoscopic treatments, e.g. photodynamic therapy and electrocautery, are currently alternatives for surgical resection. Finding more early stage cancers by screening the population at risk and accurate staging to enable treatment at the earliest stage feasible, may improve the dismal prognosis of many patients. This article deals with the clinical background and current problems in early detection of lung cancer and discusses our expectations regarding new developments in bronchoscopy for early detection, accurate staging and treatment of lung cancer.

Modeling of long-term screening for lung carcinoma

BACKGROUND

Results from the Mayo Lung Project (MLP), a randomized clinical trial for the early detection of lung carcinoma, were interpreted as proof that the early detection of lung carcinoma by chest X-ray does not reduce the mortality from this disease. Recent analysis of extended follow-up data from the MLP subjects found that after approximately 20 years there still was no apparent difference in lung carcinoma mortality between a study group and a control group.

METHODS

To view this result within context, the authors utilized a previously published simulation model of the MLP, with parametric values that were estimated at the time of the original publication based on the data collected by the MLP.

RESULTS

The model produced predictions of the extended follow-up statistics that were found to be consistent with the data published in the prior study. The authors believe this provides long-term validation for the model. Conversely, the same model demonstrated that had the study subjects been screened annually for the extended follow-up period, the difference in mortality would be noticeable, even with the low sensitivity of chest X-ray detection.

CONCLUSIONS

The results of current study strongly suggest that long-term screening with chest X-ray results in a reduction in lung carcinoma mortality. The limited extent of this benefit is the result of the low sensitivity of chest X-ray as a screening tool.

Economic decision analysis model of screening for lung cancer

The objective of this study was to evaluate the potential clinical and economic implications of an annual lung cancer screening programme based on helical computed tomography (CT). A decision analysis model was created using combined data from the Surveillance, Epidemiology and End Results (SEER) registry public-use database and published results from the Early Lung Cancer Action Project (ELCAP). We found that under optimal conditions in a high risk cohort of patients between 60 and 74 years of age, annual lung cancer screening over a period of 5 years appears to be cost effective at approximately $19000 per life year saved. A sensitivity analysis of the model to account for a 1-year decrease in survival benefit and changes in assumptions for incidence rate and costs generated cost effectiveness estimates ranging from approximately $10800 to $62000 per life year saved. Based on the assumptions embedded in this model, annual screening of high risk elderly patients for lung cancer may be cost effective under optimal conditions, but longer term data are needed to confirm if this will be borne out in practice.

Impact of FDG-labelled positron emission tomography imaging on the management of non-small-cell lung cancer

Lung cancer is currently the leading cause of cancer-related death in both men and women in most Western countries. Although 5-year survival rates have doubled from 1960s, they are low compared with survival rates for other cancer types. Tumour stage is the strongest prognostic factor and the most important parameter that guides treatment decision making. Metabolic imaging with fluorodeoxyglucose-labelled positron emission tomography (FDG-PET) has proved superior to conventional imaging for staging of non-small-cell lung cancer. This new imaging modality permits more accurate planning of treatment with surgery and radiotherapy and provides information of greater prognostic significance than what can be obtained with conventional approaches. FDG-PET has been approved in the USA and the UK as a basic and invaluable tool in the management of lung cancer. This paper reviews current trends in clinical practice on the applications of FDG-PET in the management of non-small-cell lung cancer.

Review of recent advances in fluorescence bronchoscopy in early localization of central airway lung cancer

Centrally located lung cancers are radiologically occult until so far advanced as to have a low cure rate or require extensive resection for cure, but at a cost of high morbidity. These cancers represent about one-fifth of new lung cancers. Autofluorescence bronchoscopy appears to be an important tool in localizing premalignant and early malignant lesions in the large central airways, particularly when applied to high-risk patients. Applications include studies of molecular biology of premalignancy and early malignancy, chemoprevention studies, endobronchial therapy studies, localization of synchronous tumors, estimation of the extent of field cancerization, and better estimation of resection margins. Autofluorescence bronchoscopy appears to be significantly more sensitive than white light examination but has low specificity. This technology is likely to gain widespread use when evaluation of sputum for malignant changes is both more sensitive and specific, and when its application is demonstrated to reduce mortality in this important subgroup of non-small cell lung cancer patients.

Potential cost-effectiveness of one-time screening for lung cancer (LC) in a high risk cohort

The development of low-dose helical computed-tomography (CT) scanning to detect nodules as small as a few mm has sparked renewed interest in lung cancer (LC) screening. The objective of this study was to assess the potential health effects and cost-effectiveness of a one-time low-dose helical CT scan to screen for LC. We created a decision analysis model using baseline results from the Early Lung Cancer Action Project (ELCAP); Surveillance, Epidemiology and End Results (SEER) registry public-use database; screening program costs estimated from 1999 Medicare reimbursement rates; and annual costs of managing cancer and non-cancer patients from Riley et al. (1995) [Med Care 1995;33(8):828-841] and Taplin et al. (1995) [J Natl Cancer Inst 1995;87(6):417-26]. The main outcome measures included years of life, cost estimates of baseline diagnostic screening and follow up, and cost-effectiveness of screening. We found that in a very high-risk cohort (LC prevalence of 2.7%) of patients between 60 and 74 years of age, a one-time screen appears to be cost-effective at $5940 per life year saved. In a lower risk general population of smokers (LC prevalence of 0.7%), a one-time screen appears to be cost-effective at $23100 per life year. Even when a lead-time bias of 1 year is incorporated into the model for a low risk population, the cost-effectiveness is estimated at $58183 per life year. Based on the assumptions embedded in this model, one-time screening of elderly high-risk patients for LC appears to be cost-effective.

Screening for lung cancer

BACKGROUND

The effectiveness of screening for lung cancer with chest radiography, sputum cytology or spiral CT has not been established.

OBJECTIVES

To determine whether screening for lung cancer using regular sputum examinations or chest radiography or CT chest reduces lung cancer mortality.

SEARCH STRATEGY

Electronic databases, bibliographies, hand searching of a journal and discussion with experts were used to identify published and unpublished trials.

SELECTION CRITERIA

Controlled trials of screening for lung cancer using sputum examinations, chest radiography or CT chest.

DATA COLLECTION AND ANALYSIS

Intention to screen analysis was performed. Where there was significant statistical heterogeneity relative risks were reported using the random effect model, but for other outcomes the fixed effect model was used.

MAIN RESULTS

Seven trials were included (6 randomised controlled studies and 1 non-randomised controlled trial) with a total of 245,610 subjects. There were no studies with an unscreened control group. Frequent screening with chest x-rays was associated with an 11% relative increase in mortality from lung cancer compared with less frequent screening (RR 1.11, CI: 1.00-1.23). A non statistically significant trend was observed to reduced mortality from lung cancer when screening with chest x-ray and sputum cytology was compared with chest x-ray alone (RR 0.88, CI:0.74-1.03). Several of the included studies had potential methodological weaknesses. There were no controlled studies of spiral CT.

REVIEWER'S CONCLUSIONS

The current evidence does not support screening for lung cancer with chest radiography or sputum cytology. Frequent chest x-ray screening might be harmful. Further, methodologically rigorous trials are required.