Screening for early lung cancer. Results of the Memorial Sloan-Kettering study in New York

Smoking status, occupational asbestos exposure and bronchial location of lung cancer

The objective of this study was to determine the factors associated with central airway versus peripheral bronchial location of lung cancer. All patients diagnosed with lung cancer from 1997 through 2000 in the Respiratory Disease Department of Rouen University Hospital were prospectively interviewed about their smoking and occupational history using a standardized questionnaire. All patients underwent white-light bronchial endoscopy using a 4.5 mm flexible endoscope. Tumors were classified as central when they were accessible and visible using this technique. Out of 217 cases of lung cancer included in this study, 155 (71%) were central. Histological type of lung cancer was strongly associated with bronchial location as central location was observed in 48, 82 and 92% of Adenocarcinoma (AC), Squamous Cell (SqC), and Small Cell Carcinoma (SCC), respectively (P<0.0001). Among non asbestos-exposed patients, location varied little with smoking status, with central location frequency ranging from 74 to 80%. In contrast, lung cancer was recorded central in 41% of long-term (> or =10 years) ex-smokers, 67% of short-term (<10 years) ex-smokers and 75% of current smokers (P=0.04) among patients exposed to asbestos, suggesting an interaction between duration of smoking cessation and occupational asbestos exposure with respect to lung cancer location. These findings were confirmed after adjustment for sex, age and histologic type in multivariate analysis. These results suggest that individually-tailored multimodality screening strategies relying on various combinations of low-dose CT scan, sputum analysis and fluorescence endoscopy according to each patient's profile may be more effective than standard strategies based on a single approach for all patients.

Psychological issues related to the use of spiral CT for lung cancer early detection

Although the NCI is presently investigating whether enhanced detection of lung tumors via spiral CT reduces lung cancer mortality, use of this technology for lung cancer screening is already widespread in the US. Few data are available concerning level of interest in, or awareness of, spiral CT for lung cancer screening, correlates of participation in screening, or potential reactions to screening results (i.e. smoking cessation) among high-risk individuals. One-hundred-and-seventy-two current or former smokers with no personal cancer history were queried about their awareness of spiral CT for lung cancer screening, received information about the procedure, and completed a survey that assessed interest in screening, correlates of screening interest (i.e. demographic, health, psychological), and expected effects of screening results on smoking. Seventy-seven percent of respondents were unaware of spiral CT for lung cancer screening and 62% expressed high interest in screening. Screening interest was positively related to screening self-efficacy, knowledge of asymptomatic illness, and perceived lung cancer risk. In the face of a positive scan, 52% of smokers said that they would quit, 43% said they would consider quitting, and 3% would continue smoking. If the scan was negative, 19% of smokers said that they would quit, 61% said they would consider quitting, and 20% would continue smoking. Finally, 59% of smokers were interested in smoking cessation counseling, with screening. These findings can help guide the design of psychological interventions to promote the utilization of spiral CT for early lung cancer detection as well as the development of protocols to promote behavior change within lung cancer screening programs, should future studies indicate that spiral CT screening can effectively reduce the overall lung cancer mortality rate.

Lung cancer in elderly patients

Lung cancer is one of the most common causes of death in elderly patients in the United States. Treatment advances have improved survival in selected patients. The available treatments carry the risk of morbidity and mortality but the benefit in most patients far outweighs the risks, given the dismal prognosis of untreated disease. Elderly patients with lung cancer need careful attention during pretreatment assessment. Advanced age alone, however, should not contraindicate aggressive treatment. In the high-risk groups it is important to involve a team of physicians including surgeons, radiation oncologists, medical oncologists, and pulmonologists, who are familiar with current treatment options and their risks.

Lung cancer screening with helical computed tomography in older adult smokers: a decision and cost-effectiveness analysis

CONTEXT

Encouraged by direct-to-consumer marketing, smokers and their physicians are contemplating lung cancer screening with a promising but unproven imaging procedure, helical computed tomography (CT).

OBJECTIVE

To estimate the potential benefits, harms, and cost-effectiveness of lung cancer screening with helical CT in various efficacy scenarios.

DESIGN, SETTING, AND POPULATION

Using a computer-simulated model, we compared annual helical CT screening to no screening for hypothetical cohorts of 100 000 current, quitting, and former heavy smokers, aged 60 years, of whom 55% were men. We simulated efficacy by changing the clinical stage distribution of lung cancers so that the screened group would have fewer advanced-stage cancers and more localized-stage cancers than the nonscreened group (ie, a stage shift). Our model incorporated known biases in screening programs such as lead time, length, and overdiagnosis bias.

MAIN OUTCOME MEASURES

We measured the benefits of screening by comparing the absolute and relative difference in lung cancer-specific deaths. We measured harms by the number of false-positive invasive tests or surgeries per 100 000 and incremental cost-effectiveness in US dollars per quality-adjusted life-year (QALY) gained.

RESULTS

Over a 20-year period, assuming a 50% stage shift, the current heavy smoker cohort had 553 fewer lung cancer deaths (13% lung cancer-specific mortality reduction) and 1186 false-positive invasive procedures per 100 000 persons. The incremental cost-effectiveness for current smokers was $116 300 per QALY gained. For quitting and former smokers, the incremental cost-effectiveness was $558 600 and $2 322 700 per QALY gained, respectively. Other than the degree of stage shift, the most influential parameters were adherence to screening, degree of length or overdiagnosis bias in the first year of screening, quality of life of persons with screen-detected localized lung cancers, cost of helical CT, and anxiety about indeterminate nodule diagnoses. In 1-way sensitivity analyses, none of these parameters was sufficient to make screening highly cost-effective for any of the cohorts. In multiway sensitivity analyses, a program screening current smokers was $42 500 per QALY gained if extremely favorable estimates were used for all of the influential parameters simultaneously.

CONCLUSION

Even if efficacy is eventually proven, screening must overcome multiple additional barriers to be highly cost-effective. Given the current uncertainty of benefits, the harms from invasive testing, and the high costs associated with screening, direct-to-consumer marketing of helical CT is not advisable.

Lung cancer screening with low-dose CT

Screening for lung cancer is hoped to reduce mortality from this common tumour, which is characterised by a dismal overall survival, relatively well defined risk groups (mainly heavy cigarette smokers and workers exposed to asbestos) and a lack of early symptoms. In the past studies using sputum cytology and chest radiography have failed to demonstrate any reduction in lung cancer mortality through screening. One of the reasons is probably the relatively poor sensitivity of both these tests in early tumours. Low radiation dose computed tomography (CT) has been shown to have a much higher sensitivity for small pulmonary nodules, which are believed to be the most common presentation of early lung cancer. As, however, small pulmonary nodules are common and most are not malignant, non-invasive diagnostic algorithms are required to correctly classify the detected lesions and avoid invasive procedures in benign nodules. Nodule density, size and the demonstration of growth at follow-up have been shown to be useful in this respect and may in the future be supplemented by contrast-enhanced CT and positron emission tomography. Based on these diagnostic algorithms preliminary studies of low-dose CT in heavy smokers have demonstrated a high proportion of asymptomatic, early, resectable cancers with good survival. As, however, several biases could explain these findings in the absence of the ultimate goal of cancer screening, i.e. mortality reduction, most researchers believe that randomised controlled trials including several 10000 subjects are required to demonstrate a possible mortality reduction. Only then general recommendations to screen individuals at risk of lung cancer with low-dose CT should be made. It can be hoped that international cooperation will succeed in providing results as early as possible.

Pathologic review of the Mayo Lung Project cancers [corrected]. Is there a case for misdiagnosis or overdiagnosis of lung carcinoma in the screened group?

BACKGROUND

In the Mayo Lung Project Screening Trial, there were more carcinomas identified in the screened group compared with the control group. The screened group had better survival, but there was no difference in lung carcinoma mortality between the screened group and the control group. The purpose of this study was to review all available original pathology from the trial to determine whether overdiagnosis (carcinomas that do not result in the death of the patient) or misdiagnosis of lung carcinoma may explain this discrepancy.

METHODS

All available lung pathology slides from patients who underwent surgery at the Mayo Clinic were reviewed independently by three blinded lung pathologists. Tumors were classified according to the 1999 World Health Organization criteria. In addition, agreement among the pathologists was assessed.

RESULTS

Among 106 patients who underwent surgery at the Mayo Clinic, slides were available for review from 105 patients, including 77 slides from the screened group and 28 slides from the control group. The original diagnosis of carcinoma was confirmed in all patients. In 7 patients (6.7%), there was unanimous agreement that the lesion was preinvasive (carcinoma in situ), and these lesions all were from the screened group. In 90 patients (85.5%), there was unanimous agreement that the tumors were invasive. In 8 patients (7.8%), there was some disagreement between the observers about whether lesions were invasive or preinvasive; 7 of these 8 lesions were from the screened group. The level of agreement among pathologists for invasive carcinomas was > 94% for all comparisons, and the kappa statistic ranged from 0.67 (substantial agreement) to 0.84 (almost perfect agreement). There was good agreement among the pathologists about tumor cell type with the kappa statistic >/= 0.65.

CONCLUSIONS

The histologic diagnosis of carcinoma was confirmed for all 105 slides that were reviewed. The results of this study indicate that misdiagnosis does not explain the increased numbers of carcinomas identified in the screened group. The increased numbers of in situ carcinomas in the screened group resulted in increased numbers of squamous carcinomas in the screened group compared with the control group and may have contributed to the better survival. It is possible that carcinoma in situ accounted for some instances of overdiagnosis.

Early lung cancer detection and treatment strategies

Lung cancer is the leading cause of cancer deaths in both men and women in the United States. The majority of lung cancer patients will present with advanced disease with a very poor overall survival. Although prior screening trials have shown no benefit from screening, there is renewed interest in low dose CT scanning as a screening modality for lung cancer. A high proportion of screen-detected cancers are early stage and resectable for cure. For the majority of these early stage patients, standard lobectomy is the treatment of choice. New options to potentially detect and treat early stage lung cancer will increase dramatically in the future.

Lung cancer--where are we today? Current advances in staging and nonsurgical treatment

Lung cancer remains the commonest cause of cancer death in both men and women in the developed world, although mortality rates for men are dropping. Spiral computed tomography (CT) of the chest in middle-aged, smoking subjects may identify two to four times more lung cancers than a chest X-ray, with more than 70% of tumors being Stage I. The incidence of benign nodules is high, making interpretation difficult. Randomized controlled trials are required to determine whether spiral CT detects lung cancer early enough to improve mortality. Preoperative staging has relied on CT scans, but positron emission tomography scanning has greater sensitivity, specificity, and accuracy than CT and is recommended as the final confirmatory investigation when the CT shows resectable disease. In locally advanced non-small cell lung cancer, there is a small advantage for the addition of chemotherapy to radiotherapy, but no advantage for postoperative radiotherapy. Chemotherapy gives no benefit when given as neoadjuvant or adjuvant treatment around surgery. In advanced disease, newer cytotoxic agents confer a small survival advantage over older combinations, but the advantage in median survival over best supportive care remains a few months with modest improvements in quality of life. Survival with small cell lung cancer has shown little increase over the last 15 years despite multiple attempts to manipulate the timing, dose intensity of chemotherapy, and the potential of radiotherapy. Novel therapies are urgently needed for all cell types of lung cancer.

Innovative molecular and imaging approaches for the detection of lung cancer and its precursor lesions

Current approaches for the therapy of lung cancer, the majority of which being advanced cancers, have failed to impact on long term survival. The key to improvement lies in the combination of early diagnosis and the introduction of novel targeted therapies. In this article we review some of the innovative approaches, both imaging and molecular, that are currently under investigation for early detection. Because lung cancers may arise in the central or peripheral compartments of the lung, newer approaches must target tumours arising in both of these compartments. Specimens available for analysis include sputa and blood. Detection of genetic changes in peripheral blood is a promising avenue being explored by several groups. Molecular techniques discussed include gene mutations, detection of nuclear riboprotein, methylation related silencing of genes and malignancy associated changes. Newer imaging technologies include autofluorescence bronchoscopy, virtual bronchoscopy, optical coherent tomography and confocal microscopy. Although the impact of these new technologies on survival has not been determined, they offer a wide range of exciting new approaches. In time they may completely revamp the present highly conservative and unsuccessful approaches to early diagnosis.

Characteristics of female smokers attending a lung cancer screening program: a pilot study with implications for program development

Anticipating the development of lung cancer early detection programs, we examined the: (1) feasibility of a lung cancer early detection program; (2) characteristics of enrollees (e.g. motivation to quit smoking); (3) correlates of enrollee motivation to quit smoking; and (4) rates of smoking cessation following screening. Brief surveys were completed before and after screening, which involved sputum cytology, chest X-ray, bronchoscopy, spiral CT, and a meeting with an oncologist to discuss smoking cessation. Of the 168 eligible women who were heavy smokers recruited via newspaper and cancer center advertisements, 55 agreed to undergo screening. Enrollees showed low-to-moderate levels of quit motivation and high levels of nicotine addiction; enrollees were interested in a range of smoking cessation treatments; 20% of enrollees exhibited clinical-levels of emotional distress; 64% of enrollees reported low levels of self-efficacy (i.e. self-confidence) to quit; 24% of enrollees reported low levels of quitting pros and 25% reported high levels of quitting cons; 31% of enrollees showed high levels of fatalistic beliefs about cancer; and all enrollees recognized their elevated lung cancer risk. Greater motivation to quit smoking was related to: greater age, lower nicotine addiction, fewer health symptoms, and higher quitting self-efficacy and quitting pros. Finally, 16% of enrollees quit smoking after screening. Overall, many women eligible for screening refused to undergo comprehensive screening that included bronchoscopy and spiral CT. Screening may represent an opportunity for quitting smoking, although more intensive smoking cessation interventions that target nicotine addiction and self-efficacy may be needed to maximize the health benefits of an early detection program.

Management of the solitary pulmonary nodule: directed resection

The primary goals in management of a solitary pulmonary nodule are: 1) early detection and treatment of lung cancer at a curable stage; 2) avoidance of unnecessary surgery for benign lesions; 3) efficient, economic use of resources in distinguishing between benign and malignant lesions. Management depends on the nature of the nodule, the nature of the patient, and the approach of the physician or surgeon who assumes responsibility for further evaluation and treatment of the solitary pulmonary nodule. By combining appropriate diagnostic studies, and close personal attention, unnecessary excision of benign nodules can be kept to a minimum, patient anxiety allayed and excision of cancers undertaken with appropriate staging and without compromise of outcome.

The solitary pulmonary nodule: aggressive excisional strategy

Treatment of cancer at an early stage leads to enhanced survival. Low-dose spiral computed tomography (CT) scanning is readily available and allows early detection of solitary pulmonary nodules. Thoracic surgeons should embrace a calculated yet aggressive approach to early definitive diagnosis of solitary pulmonary nodules. Sputum cytology, bronchoscopy and biopsy, image-guided fine-needle aspiration cytology, and positron emission tomography with (18)fluorodeoxyglucose (FDG-PET) scanning are useful diagnostic tools, but problems unique to each and the possibility of false-negative examination have relegated their use to selected nodules. Serial radiographic examination remains the main noninvasive test for diagnosis of solitary pulmonary nodules. Video-thoracic surgery allows resection of pulmonary nodules with minimal morbidity and mortality. Today, diagnosis by excisional biopsy is an acceptable management strategy as more and smaller nodules are being detected but not diagnosed. In 2002, when in doubt, we should take out the solitary pulmonary nodule.

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.

Diagnosis and management of early lung cancer

Bronchogenic carcinoma remains the leading cause of cancer deaths in the United States. Approximately 80% of newly diagnosed cases are non-small cell lung cancer (NSCLC); 80% of these present with disseminated or locally advanced disease. Unfortunately, only 10% are potentially surgically curable patients with early-stage disease (T1N0/T2N0). Most patients with early-stage disease are asymptomatic, with their lung cancer detected as a result of non-cancer related procedures. Studies have shown that chest radiography as a screening modality resulted in a higher discovery of early disease, but did not translate to a significant reduction in lung cancer mortality. Recent work on low-dose helical CT, however, has renewed interest in the challenge of detecting early-stage lung cancer.

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.

Misinterpretation of the chest x ray as a factor in the delayed diagnosis of lung cancer

All patients in 1997 with a histologically proved diagnosis of lung cancer in Castle Hill Hospital in whom a full set of case notes and x rays could be retrieved were studied. All previous chest x rays were reviewed by a consultant chest physician and a radiologist, who were blinded to the eventual site of the lesion and the point at which a suspicious abnormality first appeared. Case notes were inspected to clarify the cause of any error. Fifty eight patients were eligible, 28 of whom had previous chest x rays. Of these 14 were found to be abnormal. A significant difference (p=0.007) in time from diagnosis to death was found between those with a missed abnormality, median (interquartile range, IQR) 105 (55-219) days and those with no previous abnormality, median (IQR) 260 (137-512) days. In the 14 in whom the diagnosis was missed the median (IQR) delay from first abnormal chest x ray to the eventual diagnostic x ray was 101 (48-339) days. A significant difference (p=0.001) was also found between the median (IQR) time from first abnormal chest x ray to start of treatment between those with missed abnormalities, 155 (115-376) days, and those with no previous abnormality on chest x ray, 51 (44-77) days. The most common reason (47%) for the diagnosis to be missed was failure of the radiologist reporting the x ray to recognise the abnormality. It is not unusual to find previous significant radiological abnormalities in patients in whom a diagnosis of lung cancer is later made. This leads to a diagnostic delay which has a significant effect on time to initiation of treatment and palliation of symptoms, although not necessarily to eventual outcome.

Computed tomography screening for lung cancer in asbestos-exposed workers

We conducted a computed tomography (CT) screening for lung cancer in a high-risk population. Six hundred and two workers (38-81 years, 97% smokers) with asbestos-related occupational disease were screened using spiral CT and chest radiography. The national cancer registry was checked for possible false negative cases. The screening detected 111 patients with non-calcified nodules >0.5 cm in diameter and 66 of them were referred for further hospital examination. We found five lung cancers (106 false positive cases) with a histological spectrum similar to the national, natural occurrence of the disease (two adeno, one squamous cell, one anaplastic and one metastatic carcinoma) and one peritoneal mesothelioma. Three cases were potentially operable (stage I-II). Unfortunately there was one false negative fine-needle aspiration biopsy (FNAB) with misinterpretation of the follow-up CT scan and another patient who refused further investigations after an inadequate FNAB. In the end only one patient with adenocarcinoma underwent surgery. After 3 years of follow-up two new lung cancers were reported to the cancer registry with no evidence of tumour in the retrospective analysis of the screening CT scan. The sensitivity of CT screening was 100%. CT was capable of detecting early lung cancer in asbestos-exposed patients with a lot of confusing pulmonary and pleural pathology. Due to the high number of positive findings attention should be paid to patient compliance and the follow-up protocols and patient selection in future screening programmes.

Simple office spirometry

Spirometric measurements are as fundamental to medicine as are measurements of pulse, blood pressure, temperature, height, and weight. Spirometric measurements should be considered important vital signs. Any deviations from "normal" measurements can point primary care physicians toward the use of behavioral modification or effective pharmacologic agents to prevent or forestall their patients' premature morbidity and mortality from many disease states, including premature deaths from all causes.

Fluorescence versus white-light bronchoscopy for detection of preneoplastic lesions: a randomized study

BACKGROUND

There are no currently approved methods for the screening and early detection of lung cancer. We compared the ability of conventional white-light bronchoscopy (WLB) and laser-induced fluorescence endoscopy (LIFE) to detect preneoplastic lung lesions in a randomized trial in which both the order of the procedures and the bronchoscopists were randomly assigned.

METHODS

The study included high-risk subjects enrolled because of a cigarette smoking history of at least 30 pack-years, an air-flow obstruction, and either an abnormal sputum cytology (n = 48) or a previous or suspected lung cancer (n = 7). LIFE and WLB were performed on all patients. Biopsy specimens were assessed for histologic abnormalities, including the presence of angiogenic squamous dysplasia. All statistical tests were two-sided.

RESULTS

A total of 391 biopsy specimens were taken from the 55 patients. Thirty-two patients (58%; 95% confidence interval [CI] = 44% to 71%) had at least one biopsy with moderate or severe dysplasia, and 19 (59%; 95% CI = 41% to 76%) of these patients could be diagnosed based solely on the results of LIFE. LIFE was statistically significantly more sensitive than WLB for detecting moderate dysplasia or worse (68.8% versus 21.9%, respectively) (difference = 46.9%; 95% CI = 25% to 68%; P< .001). The relative sensitivities (WLB = 1.0) were 3.1 (95% CI = 1.6 to 6.3) for LIFE and 3.7 (95% CI = 1.9 to 7.3) for LIFE and WLB combined. LIFE was less specific than WLB (69.6% versus 78.3%, respectively; P = .45), but the difference was not statistically significant. The relative specificities (WLB = 1.0) were 0.9 for LIFE (95% CI = 0.6 to 1.3) and 0.6 (95% CI = 0.4 to 1.0) for LIFE and WLB combined. The results were similar regardless of the order of the procedures or the order of the bronchoscopists. Also, LIFE was better at identifying angiogenic squamous dysplasia lesions than WLB (detection ratio [DR], which indicates the relative likelihood of getting a positive result in a sample with dysplasia compared with one without, for LIFE = 1.39 [95% CI = 1.17 to 1.65] versus DR for WLB = 0.67 [95% CI = 0.38 to 1.21]).

CONCLUSION

LIFE was more sensitive than WLB in detecting preneoplastic bronchial changes in high-risk subjects. The prognostic implication of this finding is not yet clear.

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.

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.

MCM2--a promising marker for premalignant lesions of the lung: a cohort study

BACKGROUND

Because cells progressing to cancer must proliferate, marker proteins specific to proliferating cells may permit detection of premalignant lesions. Here we compared the sensitivities of a classic proliferation marker, Ki-67, with a new proliferation marker, MCM2, in 41 bronchial biopsy specimens representing normal mucosa, metaplasia, dysplasia, and carcinoma in situ.

METHODS

Parallel sections were stained with antibodies against MCM2 and Ki-67, and the frequencies of staining were independently measured by two investigators. Differences were evaluated statistically using the two-sided correlated samples t-test and Wilcoxon rank sum test.

RESULTS

For each of the 41 specimens, the average frequency of staining by anti-MCM2 (39%) was significantly (p < 0.001) greater than by anti-Ki-67 (16%). In metaplastic lesions anti-MCM2 frequently detected cells near the epithelial surface, while anti-Ki-67 did not.

CONCLUSIONS

We conclude that MCM2 is detectable in 2-3 times more proliferating premalignant lung cells than is Ki-67. The promise of MCM2 as a sensitive marker for premalignant lung cells is enhanced by the fact that it is present in cells at the surface of metaplastic lung lesions, which are more likely to be exfoliated into sputum. Future studies will determine if use of anti-MCM2 makes possible sufficiently early detection to significantly enhance lung cancer survival rates.

Detection of early-stage lung cancer: computed tomographic scan or chest radiograph?

OBJECTIVE

Computed tomography has recently been proposed as a useful method for the early detection of lung cancer. In this study we compared the stage distribution of lung cancers detected by a computed tomographic scan with that of lung cancers detected by a routine chest x-ray film.

METHODS

Two groups of patients with biopsy-proven non-small cell lung cancer were reviewed. In the first group of 32 patients, the tumors were detected by a computed tomographic scan. In a second group (n = 101), the lung cancers were detected on routine chest x-ray films. Patients with pulmonary symptoms or a history of cancer were excluded.

RESULTS

There was no difference in age, sex, or cell-type distribution between the 2 groups. A significantly greater number of patients undergoing a computed tomographic scan had stage IA disease compared with those having an x-ray film. Of the 32 patients in the group having a scan, 10 had tumors 1 cm or less in size versus 6 of 101 in the group having a chest radiograph. Additionally, there was a significant reduction in advanced stage disease in the group having a scan.

CONCLUSIONS

In this retrospective study, a higher incidence of stage IA lung cancers and significantly fewer cases of more advanced disease were observed in patients screened with computed tomography than in those having a chest radiograph. These data suggest that computed tomographic screening may be of value in improving the survival of patients with non-small cell lung cancer.

Lung cancer screening

Prior attempts to screen for lung cancer using chest radiography and sputum cytology have proved unsuccessful. Recent reports have investigated the role of spiral CT in early lung cancer detection and have suggested that screening would be of value. Prior to the introduction of a national lung cancer screening programme, it would be essential to demonstrate that this would reduce mortality and would be cost effective.

Reproducibility of the WHO/IASLC grading system for pre-invasive squamous lesions of the bronchus: a study of inter-observer and intra-observer variation

AIMS

Although many workers have graded pre-invasive squamous lesions arising in the bronchus, there has been no consensus classification system until the latest edition of the WHO/IASLC histological classification of pulmonary and pleural tumours. Because the value of any such system is dependent on its reproducibility, we have circulated a series of such lesions to a panel of histopathologists to assess interobserver and intra-observer variation when the WHO/IASLC classification was applied.

METHODS AND RESULTS

Colour transparencies of 28 pre-invasive squamous lesions were assessed by six histopathologists (two with a special interest in pulmonary pathology, two generalists and two trainees) on three separate occasions over a period of 3 months, using the criteria of the WHO/IASLC (mild, moderate and severe dysplasia, and in-situ carcinoma). An additional category of metaplasia was added for those cases that showed no dysplasia. Weighted kappa coefficents of agreement (K(w)) were used to evaluate paired observations with a standard quadratic weighting being employed, such that kappa coefficients corresponded to intra-class correlation coefficients. Wilcoxon's sign-ranked test was used to measure the statistical significance of group trends, when comparing kappa values for the three grading systems. Various 3-point systems were also assessed, through combination of the above groups. Intra-observer agreement was substantially better than interobserver variation (mean: 0.71 vs. 0.55). Between the various pathologist groups, inter-observer variation was relatively minor, although intra-observer variation was higher within the trainee pathologist group. Using weighted kappa values, there was no significant difference in either inter-observer or intra-observer agreement between the five point grading system and a 3-point system of metaplasia/mild, moderate and severe/in-situ grades. However, there was a significant increase in variation when a 3-point system of metaplasia/mild, moderate/severe and in-situ carcinoma was used.

CONCLUSION

This study shows levels of interobserver and intra-observer variation similar to those found in other grading systems in histopathology, with no significant decrease in variability found by abridging the system. The WHO/IASLC system is therefore recommended for future use in both clinical and research fields.

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.

Lung cancer after head and neck cancer: role of chest radiography

OBJECTIVE

To examine whether screening chest radiographs lead to significantly longer life span in patients found to have pulmonary lesions than in those in whom lung cancer was detected after symptoms developed.

STUDY DESIGN

A retrospective study.

MATERIAL AND METHODS

Charts of 1,086 patients with squamous cell cancer of the head and neck treated for cure from January 1, 1974, to December 31, 1998, were analyzed.

RESULTS

Pulmonary cancer developed in 62 patients. In 41 patients pulmonary malignancy was found because of patient symptoms. In 21 patients lung cancer was detected by routine annual chest radiography. Seventy-five percent of lung cancers were detected within 3 years of initial treatment of the head and neck cancer.

CONCLUSION

Chest radiography is a poor screening tool, because it failed to find pulmonary lesions in more than 65% (41/62) of patients who were later found to have pulmonary cancer. Survival rate did not differ between patients in whom pulmonary cancer was found by screening chest radiography and those in whom symptoms prompted evaluation (P = .48). Using current treatment protocols, routine yearly chest radiography did not improve survival in patients with head and neck cancer. However, there maybe new therapeutic regimens under investigation that would benefit these patients if their lung cancers were found in early stages of disease. Future directives must include the establishment of an effective follow-up protocol for the early detection of lung malignancies in these patients.

Design of the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial

The objectives of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial are to determine in screenees ages 55-74 at entry whether screening with flexible sigmoidoscopy (60-cm sigmoidoscope) can reduce mortality from colorectal cancer, whether screening with chest X-ray can reduce mortality from lung cancer, whether screening men with digital rectal examination (DRE) plus serum prostate-specific antigen (PSA) can reduce mortality from prostate cancer, and whether screening women with CA125 and transvaginal ultrasound (TVU) can reduce mortality from ovarian cancer. Secondary objectives are to assess screening variables other than mortality for each of the interventions including sensitivity, specificity, and positive predictive value; to assess incidence, stage, and survival of cancer cases; and to investigate biologic and/or prognostic characterizations of tumor tissue and biochemical products as intermediate endpoints. The design is a multicenter, two-armed, randomized trial with 37,000 females and 37,000 males in each of the two arms. In the intervention arm, the PSA and CA125 tests are performed at entry, then annually for 5 years. The DRE, TVU, and chest X-ray exams are performed at entry and then annually for 3 years. Sigmoidoscopy is performed at entry and then at the 5-year point. Participants in the control arm follow their usual medical care practices. Participants will be followed for at least 13 years from randomization to ascertain all cancers of the prostate, lung, colorectum, and ovary, as well as deaths from all causes. A pilot phase was undertaken to assess the randomization, screening, and data collection procedures of the trial and to estimate design parameters such as compliance and contamination levels. This paper describes eligibility, consent, and other design features of the trial, randomization and screening procedures, and an outline of the follow-up procedures. Sample-size calculations are reported, and a data analysis plan is presented.

Small nodules detected on chest radiography: does size predict calcification?

STUDY OBJECTIVES

To determine whether the likelihood of lung nodule calcification can be predicted from nodule size as measured on a chest radiograph (CXR).

DESIGN

Retrospective review of CXRs of patients with lung nodules < or =1 cm in size detected on CT scanning. CT images were used to identify calcifications and to provide spatial localization for readers to visualize nodules on a CXR and to measure their size. A subset of these nodules then was reexamined by different readers who did not view the CT scans

SETTING

Two university hospitals (Albuquerque, NM; Dallas, TX) and a US Air Force/Veterans Administration medical center (Albuquerque, NM).

PATIENTS

Two hundred thirty-six nodules in 185 patients

RESULTS

One half of the nodules (118) seen on CT scans could not be located on CXR, of which 8 (7%) were calcified. The prevalence of calcifications in the other 118 nodules visualized on CXRs was much higher (71 of 118 nodules [60%]; p<0.005). Among the nodules visualized on CXRs, those < 7 mm in diameter (44 of 57 nodules [77%]) were more likely to be calcified than those > or = 7 mm in diameter (27 of 61 nodules [44%]; p<0.005). Radiographs of 42 of the smallest nodules visualized on CXRs by the initial readers later were examined prospectively by different readers who did not have access to the CT images. Thirty of 33 of the calcified nodules (91%) but only 3 of 9 of the noncalcified nodules (33%) were detected (p<0.005). These readers also recorded 40 additional small nodules that were not seen on CT scans, which were considered to be false-positives.

CONCLUSIONS

Nodules detected on CXRs that measure <7 mm in size are likely to be calcified or to represent a false-positive finding.