Sensitivity and specificity of lung cancer screening in Osaka, Japan

Descriptive study of chest x-ray examination in mandatory annual health examinations at the workplace in Japan

The utility of chest x-ray examination (CXR) in mandatory annual health examinations for occupational health is debatable in Japan. This study aimed to provide basic data to consider future policies for mandatory annual health examinations in the workplace. A nationwide descriptive survey was performed to determine the rate of detection of tuberculosis, lung cancer, and other diseases through CXR in organizations associated with National Federation of Industrial Health Association. The rate of finding on CXR conducted during annual health examinations in FY2016 was evaluated. Data regarding diagnosis based on follow-up examination findings were obtained and compared with the national statistics. In addition, CXR findings were compared with the results of low-dose lung computed tomography performed at the Hitachi Health Care Center. From 121 surveyed institutions, 88 institutions with 8,669,403 workers were included. For all ages, 1.0% of examinees required follow-up examination. Among 4,764,985 workers with diagnosis data, the tuberculosis detection rate was 1.8–5.3 per 100,000 persons. For Lung cancer, 3,688,396 workers were surveyed, and 334 positive cases were detected. The lung cancer detection rate using CXR was 9.1–24.4 per 100,000 persons. From 164 cases with information regarding the clinical stage, 72 (43.9%) had Stage I lung cancer. From 40,045 workers who underwent low-dose computed tomography multiple times, 31 lung cancer cases, all with Stage I disease, were detected (detection rate: 77.4 per 100,000 persons). Our findings suggest that CXR plays a little role in the detection of active tuberculosis. With regard to LC screening, the detection rate of LC by CXR was lower, approximately 50%, than the expected rate (41.0 per 100,000 persons) of LC morbidity based on the age–sex distribution of this study population. However, the role of CXR for LC screening cannot be mentioned based on this result, because assessment of mortality reduction is essential to evaluate the role.

Referral Decision Making of General Practitioners: A Signal Detection Study

BACKGROUND

Signal detection theory (SDT) describes how respondents categorize ambiguous stimuli over repeated trials. It measures separately "discrimination" (ability to recognize a signal amid noise) and "criterion" (inclination to respond "signal" v. "noise"). This is important because respondents may produce the same accuracy rate for different reasons. We employed SDT to measure the referral decision making of general practitioners (GPs) in cases of possible lung cancer.

METHODS

We constructed 44 vignettes of patients for whom lung cancer could be considered and estimated their 1-year risk. Under UK risk-based guidelines, half of the vignettes required urgent referral. We recruited 216 GPs from practices across England. Practices differed in the positive predictive value (PPV) of their urgent referrals (chance of referrals identifying cancer) and the sensitivity (chance of cancer patients being picked up via urgent referral from their practice). Participants saw the vignettes online and indicated whether they would refer each patient urgently or not. We calculated each GP's discrimination ( d ') and criterion ( c) and regressed these on practice PPV and sensitivity, as well as on GP experience and gender.

RESULTS

Criterion was associated with practice PPV: as PPV increased, GPs' c also increased, indicating lower inclination to refer ( b = 0.06 [0.02-0.09]; P = 0.001). Female GPs were more inclined to refer than male GPs ( b = -0.20 [-0.40 to -0.001]; P = 0.049). Average discrimination was modest ( d' = 0.77), highly variable (range, -0.28 to 1.91), and not associated with practice referral performance.

CONCLUSIONS

High referral PPV at the organizational level indicates GPs' inclination to avoid false positives, not better discrimination. Rather than bluntly mandating increases in practice PPV via more referrals, it is necessary to increase discrimination by improving the evidence base for cancer referral decisions.

Sensitivity and specificity of lung cancer screening using chest low-dose computed tomography

Lung cancer screening programmes using chest X-ray and sputum cytology are routinely performed in Japan; however, the efficacy is insufficient. Screening using low-dose computed tomography (CT) is a more effective approach and has the potential to detect the disease more accurately. A total of 7183 low-dose CT screening tests for 4689 participants and 36 085 chest X-ray screening tests for 13 381 participants were conducted between August 1998 and May 2002. Sensitivity and specificity of lung cancer screening were calculated by both the detection method and the incidence method by linkage of the screening database and the Cancer Registry database. The preclinical detectable phase was assumed to be 1 year. Sensitivity and specificity by the detection method were 88.9 and 92.6% for low-dose CT and 78.3 and 97.0% for chest X-ray, respectively. Sensitivity of low-dose CT by the incidence method was 79.5%, whereas that of chest X-ray was 86.5%. Lung cancer screening using low-dose CT resulted in higher sensitivity and lower specificity than traditional screening according to the detection method. However, sensitivity by the incidence method was not as high as this. These findings demonstrate the potential for overdiagnosis in CT screening-detected cases.

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%.

Early detection in lung cancer. Case finding and screening

There is general agreement that the most effective approach to lung cancer is primary prevention--stop smoking. Richards has proposed the MVROCST--the Monosyllabic Verbal Response Office Cancer Screening Test: "Do you smoke?" If "yes," intervene. If "no," move on. Ample evidence exists that a clear message from a physician to a patient about the importance of stopping smoking makes a difference. In contrast to the maze of arguments and data on early detection, this is something that each physician clearly can and should do. A reduced risk for lung cancer may begin as early as 5 years after cessation of cigarette use. Huuskonen has proposed conceptualizing screening as a coordinated intervention with the goal of identifying populations at risk and working to modify that risk. Primary prevention should be central to any efforts to reduce mortality from lung cancer, and attention to this area needs to increase despite the difficulties and frustration. Despite declining percentages of smokers in the population as a whole, it is estimated that more than 3000 teenagers become regular smokers each day in the United States. In this environment, the question of whether to recommend a CXR or sputum for early detection is not going to disappear in the near future. The NCI has recognized the persistent and important nature of this debate and is currently funding the Prostate, Lung, Colon and Ovary Cancer Screening Trial. This is a large and powerful randomized study of men and women aged 60 to 74. The lung cancer arm is designed to look at the usefulness of a yearly CXR intervention in reducing cancer-specific mortality. The overall power of the study (based on national mortality data) is 0.99 for a 15% reduction in lung cancer mortality and 0.89 for a 10% reduction, with differentially better sensitivity in men than women. The study is currently in progress at multiple sites and will be completed over the next 12 to 14 years. In the meantime, what is the right approach? It is useful in considering this question to return to the concepts of early detection, screening, and case finding. 1. Early detection in lung cancer remains a concept of uncertain applicability because of the unknowns and variability in the natural history of the disease. The available, accessible, and acceptable detection tools appear to be inadequate by current evidence. This is not a static field, however, and new work in the area of biomarkers carries promise for significantly more sensitive and specific techniques. Tockman and colleagues conclude that early detection is conceptually sound, although not currently practical, and further research may expand the role of intervention. In the end, a judgement on early detection in lung cancer must be linked to the proposed setting--screening or case finding. 2. Screening, defined as the application of a test to the general population to define disease risk further with the implied benefit of improved treatment and outcome, cannot be recommended for lung cancer. This is the perspective of the major organizations cited previously, and it is based on admittedly imperfect but nonetheless convincing data. 3. Case finding, the situation of the patient who seeks care and is available for informed discussion and negotiation on possible testing, is a potentially different situation.(ABSTRACT TRUNCATED)

Limitation of annual screening chest radiography for the diagnosis of lung cancer. A retrospective study

BACKGROUND

The incidence and mortality rates of lung cancer have been increasing in many countries. However, the true effectiveness of screening for lung cancer is still controversial. This study aimed to examine the growth pattern of lung cancer and to evaluate the efficacy of screening.

METHODS

The authors linked the records of annual radiologic screening to cancer registry data and conducted a retrospective follow-up study of radiographs in all patients with lung cancer arising in a population undergoing screening.

RESULTS

Among a total of 305,934 participants, screening detected 206 lung cancers, 103 of which were Stage I disease. Seventy-one of the 131 adenocarcinomas were Stage I, and 58% of them showed evidence of cancer for 2 years on a retrospective review of radiographs. Presentation as small faint lesions overlapping the normal chest structures delayed the early detection of adenocarcinoma. The overall sensitivity of screening was 70%, 52% for squamous cell carcinoma and 50% for small cell carcinoma. Rapidly growing Stage II-IV tumors without retrospective evidence of cancer on previous radiographs accounted for most of the cancers detected during the intervals between screening.

CONCLUSIONS

Both the low detectability of Stage I adenocarcinoma and the late recognition of rapidly growing small cell and squamous cell carcinomas reduced the effectiveness of screening. More effective imaging methods and an antismoking campaign are required to reduce lung cancer mortality.

The impact of surgery on the multidisciplinary treatment of bronchogenic small cell carcinoma (updated review including ongoing studies)

Recent results of studies on patients with SCLC treated by surgery with curative intent followed by adjuvant chemotherapy demonstrate a definite progress in comparison to non-surgical-treatment programs for patients with comparable stage of disease. Of 186 randomized patients enrolled for the multicenter cooperative ISC-Study I and II, 76 patients with stage pT1-3N0M0 received surgery for cure followed by chemotherapy and selective radiotherapy to the brain. The projected 4 year crude survival rate by September 1991 was 57%. In 27 of 43 patients with stage pT1-3N2M0, the tumors were completely resected, resulting in a 4 year survival rate of 32%. The survival curve for both groups of patients shows a sharp bent at 27 months postoperatively, whereafter the survival curves take a plateau-like course. These promising results were confirmed by several other groups. They are in favour of initial surgery for resectable tumors, followed by postoperative chemotherapy, while patients on preoperative chemotherapy followed by adjuvant surgery showed less favourable results.